Software Intervention ~ Takumar 28mm f/3.5 SMC vs Sigma 24mm f/3.5 DG DN

One of the basic assumptions about lenses for photography that I have accepted unchallenged is that new lenses would be "obviously better" than old lenses.  My thinking was that modern optical design tools improve optical products in meaningful/useful ways leading to technically "better" photographs.

Images loaded into image processing software undergo many adjustments _before_ a starting image is displayed.  Some of these adjustments make optical defect "corrections."  Which made me wonder about the aforementioned optical design tools.

Turning software automation off often reveals an interesting, unexpected truth.  Modern lenses may _require_ software intervention to look good.  In many ways old manual focus lenses look better.  Old lenses often exhibit less geometric distortion, less chromatic aberration, and display certain level of "sharpness", even at wide apertures.  By comparison, some of the the modern lenses I own appear to benefit from a little software help.  

This little "discovery" lit up my brain cells and got me to thinking.  What if I applied lens corrections to manual focus lenses?  Specifically, what if I corrected for chromatic aberration and geometric distortion?  Not that old lenses need much geometric distortion correction, that is.  What effect might software intervention have on old lenses?

Post-Pandemic I found myself once again exploring manual focus optics.  Previously I'd made a decision to move to all modern AF but, it appears, an Old Itch still needed to be scratched.  I now have several beautiful Takumar, ever more Nikkors (including one particularly early SLR F-mount lens), Pentax-M, and third party Kiron.

Recently, I found myself in a favorite location and took two similar focal length lenses off to a car show. One lens was a new Sigma 24mm f/3.5 DG DN.  I really like this lens.  It's light, sharp, and the AF is blazing fast.  It has never let me down and is a jewel of an optic.

The other lens was an old c.1970's Asahi Takumar 28mm f/3.5 SMC (version 2).  It is a multi-coated 49mm filter thread later version of that focal length.  It, too, is very light, compact, very smooth focusing, and relatively quick and easy to use.  In fact, it, too, is a little jewel of a lens.

Setup ~ 

• Sony A7RII set on a tripod 
• 2 second self timer
• ISO100 
• Images shot at f/11

Image processing ~

Deployed four RawTherapee tools, starting from a "neutral" profile (thereby avoiding  automated software intervention) -

• Demosaic 
• Color management (Sony Camera "Standard" .dcp)
• Automated Chromatic Aberration correction ~ RAW -> chromatic aberration
• Capture Sharpen image sharpening ~ RAW -> Capture Sharpen (note: not USM)

Here is an example of what I see -

 

Comments ~

I once again confirm for myself that software intervention can be quite useful, regardless of the vintage of a lens.  In fact, old lenses tend to require less software intervention.

If I didn't already know which lens was which, there's no way I would be able to tell the difference between the old Takumar and the new Sigma.  Can you see any meaningful difference?  Maybe my eyes are getting old, but I can't.

While this is just one very small, minor example of what software intervention can do for images taken with old manual focus lens compared with modern AF .lcp enhanced optics, I see similar things with nearly all my old lenses. 

Software Intervention ~ a few musings

Back when dinosaurs roamed the earth I photographed using film and printed my own black and white images.  For a short time (four years) I printed for various labs around southern California.  My colleagues and I were involved in various projects, including making limited edition runs of various things for different galleries and producing prints for exhibitions and portfolios of famous photographers.

I felt I had a good working knowledge of the requirements that met customer expectations.  To meet those requirements, our equipment and chemical processes were carefully controlled.  Our enlargers were carefully aligned (Omega D-series were easy compared with Beseler).  The enlarging lenses we used were the best we could find (EL-Nikkor, Schneider Componon-S). The chemicals were mixed in a consistent way and temperatures were carefully monitored.  We used densitometers to verify everything was as expected.  Lamps were left on to ensure constant temperatures in condenser enlarger heads and we waited a moment after putting a negative in carrier into the enlarger so the negative would snap into flatness (if it matters and you don't understand what I just said, ask and I'll try and explain a little further).  Global image contrast was controlled by selecting paper types and/or filters.  Local corrections were made using dodging/burning techniques.

We did all these things to make certain the field of film grain would be absolutely sharp from extreme corner to extreme corner across the entire print while working to reveal the subject/scene in all its potential glory.  Making good prints was a mixture of alchemy, art, and craft.

Digital image processing comes with a few more tools than what were available to us "back in the day."  Using these tools helps us to go beyond what was done in the Old Dinosaur Film Days. 

Mulling such things over in my mind, I thought it might be interesting to comment a little on the topic.  Here's a list of things we can do in digital to "improve" a basic image beyond film era global contrast and local dodging/burning.  We can now correct/control:

• Optical distortion (pincushion, barrel)
• Chromatic aberration
• Optical vignetting (illumination fall-off around the edges)
• "Sharpness"
• "Local contrast" 

Here's a short list of the kinds of things that won't be corrected/controlled with neither film nor digital. 

• Optical coma effects
• Optical field curvature (field flatness)

There is (at least) one thing printing from film could do that is more than a little different in digital, and that is image enlarging.  Non-contact printed film sizes obviously require enlargement.  Digital is a different beast, though digital tools exist that enable enlargement possibilities.  I've found G'Mic's DCCI2X and CNN2X upscaling tools to be fairly convincing in taking a 42mpixel image and turning it into a 160+mpixel monster.

I've said a few things about how I feel I can make an old film-era lens look like a new digital-age one.  Using automated chromatic aberration correction and Capture Sharpen in RawTherapee takes my images a long ways toward matching the performance of my new digital AF Zeiss.  If an old lens suffers from lower contrast, a gentle Local Contrast and/or USM application finishes the job.

Taking the Insanity a little further, yesterday I downloaded a Leica Q2 .dng file and looked at it long and hard.  Given Leica's reputation I thought I might see some magic that's not commonly seen in other camera systems.  However, I wasn't "grokking" it, so I turned on/off the various software interventions... and... oh!... sure enough, image processing corrects/changes the outcome, even with hugely expensive Leica.

It's all rather exciting, actually.  Digital image processing software intervention can "democratize" image quality.  

Old lenses?  New lenses?  Apparent image "sharpness?"  On some level it's pretty much all the same.  Which is, I'm sure, partially the point some people try to make when saying things like "equipment doesn't matter."  Of course "equipment matters", but maybe not just in ways I usually think.

One Last Thought: There's something of a community of old lens user-commenters ("influencers?" - perish the thought) on various sites/platforms spouting/touting/sprouting the benefits of using old lenses.  They tend to say things like "old lenses have so much "character"..." and "modern lenses are so "clinically" sharp..." If what they want is "character" maybe they should try turning off software intervention on modern lenses and see what happens.  It might boggle/confuse/re-inform their world view.  Not that there's anything wrong with using old manual focus lenses, right?

Software Intervention ~ chromatic aberration, capture sharpen, local contrast, and USM corrections on a Super Cheap Kiron 28mm f/2

In the prior post I looked at chromatic aberration and capture sharpen corrections on a beautiful old Nikon Nikkor-S 50mm f/1.4 c.1972 lens.  I then took a small step to see what controlling local contrast and adding a very light USM might have and found the old Nikkor could match (under many circumstances) the performance of a Sony 55mm f/1.8 FE ZA that was managed by the common and now customary lens correction profile (.lcp) file.

For this post I want to consider similar software interventions on an incredibly inexpensive Kiron 28mm f/2 as well as a cheap, widely available Pentax-M 28mm f/2.8.  Nobody seems to like these lenses and prices on the open market tend to reflect this thought. 

Setup ~ 

• Sony A7 set on a tripod 
• +1EV (because of the strong whites and knowing whites saturate at EV+3.5) 
• 2 second self timer
• ISO100 focusing on the central flower
  
• Images made at f/2.8 and f/5.6
• Processed in RawTherapee 

Voila! encore a mundane scene of my Rescue Orchid - 

 

 

 Taking five processing steps and sharing the results in the following image -

• Demosaic and only color management as the starting point
• Add RAW -> chromatic aberration correction to the starting point
• Add Capture Sharpen to chromatic aberration, demosaic, and color managed image
• Add Rawtherapee -> Detail -> Local Contrast very light amplitude = 0.05
• Add Rawtherapee -> Detail -> Sharpening USM

Comments ~

Well, well, well... would you have a look at that, will 'ya?  Incredible, isn't it?  Or, if you've become somewhat jaded to the whole exercise, like me: Huh.

Identifying the tools .lcp files use to correct modern AF lenses and then applying that knowledge to isolating and using similar tools on old manual focus lenses has shown me several things.

First, in surprisingly many ways, modern lenses require software intervention to look as good as they do.  Second, designers of earlier lenses, using by today's standards rather rudimentary calculations, were able to achieve decent performance in terms of field flatness, field distortions, and chromatic aberration.

While there may be little to nothing software can do to correct for field flatness, coma at wide apertures in high speed lenses, or resolution fall-off toward the edges of a field (such is commonly seen in early wide angle lenses at the extreme corners), software intervention seems to work wonders on old lenses in just about ever other way.

From my perspective there is nothing to fear from using old lenses.  To prove this point I may post a few images I've recently made to see if people can tell which lens made which image.  I know, I've played this game before, so we'll see.

If a person can't make a decent image, it's likely not the fault of the lens, regardless of the age of the optic.

Chromatic Aberration ~ software intervention Nikon Nikkor-S 50mm f/1.4 vs Sony 55mm f/1.8 FE ZA

Now that I was on a roll looking at chromatic aberration and sharpness software tools I hauled out an old Nikon Nikkor 50mm f/1.4 c.1972 and a currently manufactured Sony 55mm f/1.8 FE ZA. 

What follows is actually the second pass that I made at this specific comparison.  I tried photographing the Rescue Orchid against strong backlight and found the Nikkor-S flares badly.  So I flipped the scene around and shot with the light coming from behind me.  Chromatic aberration was still present, so I was able to process the way I've learned works well.

Then I took two additional software tools and tried to match the output of the Nikkor-S to that of the Sony 55mm.  I wanted to confirm what I already suspected, which is to say, with a little help, old lenses image might be made to look every bit as good as new.

Setup ~ 

• Sony A6300 set on a tripod 
• +2EV (because of the strong whites and knowing whites saturate at EV+3.5) 
• 2 second self timer
• ISO100 focusing on the stick 
• Images made at f/5.6 and f/11
• Processed in RawTherapee 

Voila! encore a mundane scene of my Rescue Orchid - 

 

 

Three processing steps and sharing the results in the following image -

• Demosaic and only color management as the starting point
• Add RAW -> chromatic aberration correction to the starting point
• Add Capture Sharpen to chromatic aberration, demosaic, and color managed image

Using  

• Rawtherapee -> Detail -> Local Contrast 
• Rawtherapee -> Detail -> Sharpening 

 I took a quick look at matching the Nikkor-S to the Sony FE.

 

Comments ~

As in prior comparisons I see that the automated chromatic aberration correction does a fine job here.  There's not much CA in the Sony FE, so this lens is easy on the CA tool.  There is a bit more CA in the Nikkor, but this, too, cleans up quickly and nicely.

The Nikkor-S has less local contrast and is a touch softer than the Sony FE after CA correction and Capture Sharpen.  Adding two tools, then gently nudging the local contrast and USM sharpness I was able to show myself that at f/5.6 and f/11 the Nikkor-S and Sony FE have little useful/important/visible difference between them.

 

Chromatic Aberration ~ software intervention Nikon Nikkor-P 10.5cm f/2.5 c.1959/1960

Once I sorted out how to apply chromatic aberration software corrections to old manual focus lenses I set about to have a look at a few of my oldest lenses, beginning with a well used, mostly clean glass Nikon Nikkor-P 10.5cm f/2.5 9 aperture blade "tick-mark" transition c.1959/1960 lens.

To review, here's how I enabled automated chromatic aberration correction in RawTherapee.

 Rawtherapee -> RAW -> Chromatic Aberration Correction -> select Auto-correction

Pretty simple, right?

Setup ~ 

• Sony A6300 set on a tripod 
• +1EV (because of the strong white back-light) 
• 2 second self timer
• ISO100 focusing on the stick 
• Images made at f/2.5, f/4, f/5.6, and f/8
  
• Processed in RawTherapee 

Voila! encore the mundane scene of my Rescue Orchid - 

 

 

I took three processing steps and share the results in the following image.

• Demosaic and color management only as the starting point
• Add RAW -> chromatic aberration correction to the starting point
• Add Capture Sharpen to chromatic aberration, demosaic, and color managed image

Comments ~ 

There's not much to say.  It's obvious there is little CA in this lens.  It renders beautifully at all apertures.  Using chromatic aberration and "sharpness" software intervention on this optic feels like it brings this ancient lens right into line with modern products quite nicely.

Chromatic Aberration ~ software intervention Nikkor, Pentax-M, Takumar

Looking at software intervention for correcting chromatic aberration in a new Sigma 24mm f/3.5 i-Contemporary lens and learning just how important (reliant?) lens correction profiles can be to image processing, I turned my attention to three old manual focus lenses to see what might be done for them.  The challenge is, of course, that there are no lens correction profiles (.lcp) files for old lenses.

Fortunately, RawTherapee provides a surprisingly complete set of tools to work with.  Opening this software I see a tool that might be useful for correcting chromatic aberration.

Rawtherapee -> Transform -> Chromatic Aberration Correction 

There are two sliders to work with and I can look at contrasty edges of a subject and use the tool to remove CA color tints.  I can then save the settings as a recipe and recall it later as needed.

Looking around the software a bit further I stumbled upon an automated method.

 Rawtherapee -> RAW -> Chromatic Aberration Correction -> select Auto-correction

This tool automatically detects and removes CA shortly after demosaicing an image.  This tool appears to operate earlier in image processing than the Transform CA tool.  All I need to do is save a single recipe with the RAW CA correction enabled and I no longer have to store individual lens recipes.  This is the tool I used in the following comparison.

Setup ~ 

• Sony A6300 set on a tripod 
• +1EV (because of the strong white back-light) 
• 2 second self timer
• ISO100 focusing on the stick 
• Processed in RawTherapee 

I compared three old manual focus lenses ~

• Nikon Nikkor 24mm f/2.8 Ai
• Pentax-M 28mm f/2.8 
• Takumar 28mm f/3.5 SMC (second version)
  

Voila! a mundane scene of my Rescue Orchid - 

 

 

In RawTherapee and for each of the three lenses I took three processing steps and share the results in the following image.

• Demosaic and color management only as the starting point
• Add RAW -> chromatic aberration correction to the starting point
• Add Capture Sharpen to chromatic aberration, demosaic, and color managed image

 

Comments ~

 

RawTherapee's automated chromatic aberration correction tool works the treat.  It cleans up the CA tints and my impression is that an image becomes sharper in just this one simple step.  Then, with the addition of Capture Sharpen, images from old manual focus lenses can match their modern optical counterparts.

 

The old lenses I used here showed less CA than the Sigma 24mm I compared them against.  These lenses must be lighter on the tool to achieve similar results. Modern versus old?  At this level it doesn't seem to make much difference.  

 

My Nikon Nikkor 24mm f/2.8 Ai produces images that have felt "fat" to me.  I've often wondered about that.  Now I understand.  The "fatness" comes from un-corrected CA.  When the CA is cleaned up I doubt anyone could tell the difference between the old Nikkor and the new Sigma.  Images are "clinically" sharp after a little processing.

 

All hail software intervention.

Chromatic Aberrations ~ software intervention and a Sigma 24mm f/3.5 i-Contemporary

It was rather surprising to me that my Sigma 24mm f/3.5 i-Contemporary lens shows as much chromatic aberration as it does.

 

If I believed the Marketing Wizards I would've thought computer optimized optical design (such as what I was led to believe is used in current auto-focus lens design) would've been a vast improvement over earlier hand calculations (such as what was generally used to guide manual focus lens design).  Clearly this is not always the case.  There is something more going on.

 

Image processing software comes with lens correction profiles.  They correct for geometric distortion, vignetting, and chromatic aberration.  So I thought I'd have a look at how .lcp files modify the character of a currently manufactured lens.

 

I'm not sure if users can select individual corrections in RentWare products.  I imagine that people don't know nor care about the underlying automation.  In the case of RawTherapee, I _can_ select the corrections I want and I use this ability for this comparison.

 

Setup ~

• Sony A6300 set on a tripod
• +1EV (because of the strong white back-light)
• 2 second self timer, ISO100
• focusing on the stick
• Processed in RawTherapee 
  

Voila! a mundane scene of my Rescue Orchid - 

 

 

In RawTherapee I took three processing steps and share the results in the following image.

• Demosaic and color management only as the starting point
• Add chromatic aberration correction to the starting point
• Add Capture Sharpen to chromatic aberration, demosaic, and color managed image

 

 

Comments ~

 

The effects of software intervention on image processing should be rather obvious.  My Sigma 24mm f/3.5 i-Contemporary lens goes from showing a lot of chromatic aberration to becoming a sharper looking image at the first step of software chromatic aberration control. Then adding Capture Sharpen and the image takes another leap in perceived "sharpness."  After applying just these two software tools the lens behaves very well.

 

Which raises another question: Are there any tools a person can use when shooting with old lenses?  Can software correct chromatic aberrations in old lenses that do not have lens correction profiles?  I will try to answer this in the next blog post.

Chromatic Aberrations ~ new vs old lenses

I'm not sure how it came to me, but I had a question of how chromatic aberrations might effect the appearance of "sharpness" in an image and took five lenses of relatively different vintages to have a look.

Software automation can correct for various optical "defects", including field distortion, chromatic aberrations (CA), and "sharpness."  As a first step for my comparison I would need to turn all of that off to note what just the lens was doing.

You see, I had the sneaking suspicion that modern lenses were being tweaked into fabulous goodness by lens correction profile, or .lcp, files that are often hidden from a user during RAW image processing, but I wasn't sure.  I'd heard over the years many marketing claims as to new lens design technologies improving all manner of traditional optical defects, so maybe the .lcp files weren't doing as much as I thought?

The lenses on hand included:

• Nikon Nikkor 24mm f/2.8 Ai
• Pentax-M 28mm f/2.8
• Sigma 19mm f/2.8 EX DN E
• Sigma 24mm f/3.5 i-Contemporary
• Takumar 28mm f/3.5 SMC (second version)

Using a Sony A6300 set on a tripod, +1EV (because of the strong white back-light), 2 second self timer, ISO100, focusing on the stick, then processed in RawTherapee using only the demosaic and Camera Standard tone-curve enabled color management steps (to keep software processing to an absolute minimum).  

Voila! a mundane scene of my Rescue Orchid - 

 

There were a few surprises awaiting me.  Looking for chromatic aberration, here's what I found  -

Comments -

The Sigma 24mm f/3.5 shows the strongest chromatic aberrations of the five lenses I looked at whereas the old Pentax-M and older Takumar 28mm lenses show the best CA corrections.  Even the Nikkor 25mm appears to show less CA than the Sigma 24mm and is perhaps better at CA correction than the Sigma 19mm f/2.8 APS-C.

Looking at how CA effects the sense of "sharpness" I see that, yes, indeed, images look less "sharp" when CA is stronger.  Makes me wonder how much modern lenses rely on software intervention to make them look as good as they do?

Countering the rising costs of photography ~ On Being A BottomFeeder

Thom Hogan has written an excellent article that observes and comments on the rising costs of photography and the sources of those costs.

Being the contrarian penny pincher that I am, I thought I'd give a few examples of how I no longer "play that game."  In fact, I've not "played that game" for decades.

When I had a job and could afford such things I would buy new pieces of camera equipment from time to time. The last new camera I bought was a Sony A6000, and that was well over ten years ago.  Though, thinking about it a moment, maybe the last new camera I bought was a Sony A5000.  The memory fades.

Most of my efforts however, even when I worked, were buying/using/selling used gear.  Hundreds and hundreds (more likely thousands) of lenses and cameras have passed through my hands over the years.  The habit carries forward into the present.

On the image processing side of things I leveraged my knowledge of and contacts with the Open Source community, and experiences of deploying large scale Linux systems.

So, my costs have been traditionally low.  I see no reason why someone truly interested in photography either as a hobby, artist, or working professional can't do something similar.

Sony A7RII, Sony FE 35mm f/2.8 ZA
RawTherapee, Digital Zone System
Pt/Pd tinted

Here are a few things I do.

Buy Used -

It seems like an obvious place to start. 

If I worried about reliability the thing I note is that most of my used cameras these days are very "low mileage."  One Sony A7 I bought had around 800 clicks on the shutter, looked well cared for, and set me back 450Euro five years ago.  Another had less than 2,000 clicks for a slightly lower price, again, five years ago.

On the other end of the spectrum, I recently picked up a Sony A7RII with 72,000 clicks for a nice low low price.  This, even though the camera remains in excellent condition and the shutter is rated for 500,000 clicks.

Similarly, used lenses can be attractively priced.  For less than the price of a new Sony A7III body (even on sale) I've been able to build an A7 kit with three fixed focal length lenses.  Two lenses are usually expensive Zeiss labeled and one is like new latest generation Sigma.  All are auto-focus, modern optics.

Thinking again about reliability, of all the used gear that's passed through my hands, there's not one single "bad deal" that I can recall. I take that back.  I bought a Fuji 240mm A f/9 large format lens many years ago that arrived with difficult to see sand-impacted front element.  It was returned for a full refund and the seller apologized.  He remembered he'd recently taken the lens to Death Valley where it had been windy.

Image Processing -

I tend not to spend too much on computers and stick to using a laptop.  Any decent quality device will do.  HP, Dell, and, hmmm... that's about it, actually.  For security reasons I assiduously avoid anything designed/manufactured/marketed by the Chinese.

Once an inexpensive computer is at hand, I wipe the disk and install a decent distribution of Linux.  That OS remains for me the most secure way of engaging the world.

On top of Linux I load the image processing applications I like.  These include RawTherapee, the Gimp, Luminance HDR, and Hugin.

I use RawTherapee for performing the "heavy lift" image processing.  When I need to "tweak" something or want work graphically I transition to the Gimp.  While I've not done a lot of HDR recently, I still low Luminance HDR, just in case.  When the bug hits and want to make my computer cry I use Hugin to stitch very large high resolution images.

Over the years I've paid close attention to differences between commercial and Open Source software capabilities.  What I've found is that Open Source software can be more complex and require more steps to accomplish common tasks.  Coming from commercial software where many potentially important details are hidden from users, Open Source software can be a little overwhelming at first.  

Part of the challenge is that there are so many options and tools and standards that is seems as if nothing is being left out.  However, and this is important to me, once I understood the tools and specifications implemented by those tools, I've come to realize there is nothing more flexible, more comprehensive, nor more accurate (in particular color management) than something like, say, RawTherapee for image processing. 

In fact, if I felt I couldn't live without Adobe "color science" or Fuji "film simulations" or Hasselblad "Natural Colors", all I'd have to do is load the .dcp and .icc files into RawTherapee and select the styles and looks I want during processing.

To back everything up, I buy new USB drives.  This is one thing I will not buy used.  New 5tb spin drives are shockingly inexpensive.  Solid State drives are becoming more affordable.  Everything, RAW files, processed images, documents, works in progress, everything, gets tossed onto a drive every so often.  And I'm tending to keep multiple backups, too, "just in case" something fails down stream.

That's just about it.  Very simple.  Very straight-forward.  Nothing fancy.  I don't pay rent on any software.  No Apple tax.  No Microsoft madness.  No Adobe rent until I die silliness.  I own my cameras and lenses outright and at as low a price as the market offers.  I don't get a boatload of noisy advertisements from the apps and OS I use.  My systems are secure, stable, extensible, and portable.

There you have it.  This is how I manage my photography eco-system costs while living on a fixed income.

Round Three ~ Nikon Nikkor 85mm f/2 Ai and Friends

[Please note: I failed to focus the 135mm Nikkor f/2.8 AiS carefully enough in this comparison. While what I write is true, it relates _only_ to this comparison.  I've gone back and re-checked the resolution wide open.  I've confirmed my earlier observations that my copy of the 135mm f/2.8 Nikkor is indeed just a touch sharper than my copy of the 105mm Nikkor-P. Which is to say, the performance of these two Nikkors are incredibly close to my copy of the Sony FE 55mm f/1.8 ZA.~ 27 December 2024]

I have bought and sold three of these over the years and I really need to stop the constant swapping and looking for "better" or "majick."  Really, I do need to stop.  So this is it.  Hopefully this will be the last Nikon Nikkor 85mm f/2 Ai I dance with.

Across the "interwebs" it's easy to read various people's comments and thoughts on nearly everything.  The word on the street is that the Nikon Nikkor-H/HC/K 85mm f/1.8 has more "character" than the f/2.  And the word on the street is that the Nikon Nikkor-P 105mm f/2.5 is sharper than the f/2 85mm.  The Nikon Nikkor 135mm f/2.8 AiS seems to be unloved.  There is no word on the street for that one that I can find.

I've at various times bought and later sold three Nikon Nikkor-H/HC/K 85mm f/1.8 lenses, so my closet is empty of those just now.  Some say it's sharper than it's younger f/2 sister.  I've not found that to be the case.  At the same time the f/1.8 "does something swirly" to the out of focus background.  If you like "swirly", that is.  Frankly, I'm a little ambivalent about "swirly" since the highlights seem to always have hard edge "cat eyes" which to me feels strange.

Using the famous Sony FE 55mm f/1.8 Zeiss as a reference (everyone who's anybody says it's fabulous ~ have I been "influenced"?) I thought I'd have another look at comparing four lenses.  Here's what I see.

Comments -

Wide open performance from best to worst:

• Sony FE 55mm f/1.8 Zeiss
• Nikon Nikkor-P (Xenotar) 105mm f/2.5 pre-Ai
• Nikon Nikkor 135mm f/2.8 AiS
• Nikon Nikkor 85mm f/2 Ai

The Sony FE 55mm f/1.8 Zeiss is a touch soft wide open.  Stopped down to f/2.8 and f/4 it is nice and sharp.  Here's the thing, I seldom shoot the Sony FE 55mm f/1.8 Zeiss less than wide open (see here for one example) and have been completely satisfied with the results.  Hold this thought.

The 105mm Nikkor-P is nearly as sharp as the Sony 55mm, with the 135mm f/2.8 AiS another eyelash behind these two.  Something I find interesting about this is that I'm looking at four different lens designs from three, maybe four different eras of commercial optical development.  Hold this thought, too.

The Nikon Nikkor 85mm f/2 Ai is the softest of the bunch wide open.  Stopped down one or two clicks cleans things up nicely.  In fact, all four lenses stopped down a click or two look remarkably similar in terms of "sharpness."  The 85mm f/2 stands out in this group of optics for it's lack of "sharpness" wide open.  It's clearly behind the other lenses seen here.

Which leads me back to held thoughts.

The 105mm Nikkor-P is the oldest design in this group and yet it is nice and sharp from wide open.  Conventional "interwebs" wisdom would have us believe it should be the softest of the bunch.  But that's not how optical design and manufacturing historically work.  How to make a sharp lens has been known and the manufacturing process well understood for over a hundred years.  To underscore this point, the Nikon Nikkor-H 50mm f/2 Gauss design is bitingly sharp from wide open.  It's not for the lack of design and manufacturing knowledge that lenses are "unsharp" wide open.

OK, then, what's going on with the pretty little Nikon Nikkor 85mm f/2 Ai? Why is it visibly softer wide open than the other lenses seen here?  After-all, it was designed sometime in the late 1970's perhaps just a couple months ahead of the very sharp from wide open 135mm f/2.8.  

Given that Nikon knows how to design lenses I have to believe that the 85mm's spherical aberrations at f/2 are intentional. The veiling spherical aberration softness at f/2 is nearly gone by f/2.8 and is completely gone from what I can tell by f/4.  If they wanted to, Nikon could have designed a bitingly sharp 85mm at f/2.

Bottom-line:   I'll bet dollars to doughnuts Nikkor 85mm f/2 was intentionally designed to be soft/sharp at f/2.  And I'll bet euros to beer that this lens was very specifically designed as a _traditional_ portrait optic.  Which is why I'm betting that at f/2 the Nikon Nikkor 85mm Ai is _meant_ to soften skin tones.  Now _here_ is a lens with "character."  The effect is _designed_ into the lens.  It's a portrait lens when shot wide open.  It's a general purpose lens when stopped down.

Have a look at the following and tell me I'm wrong.

Nikon Nikkor 85mm f/2 Ai at f/2
Sony A7RII
Electronic first curtain OFF
IBIS set to 85mm

Digital Zone System ~ Validation Testing

I wanted to prove to myself something about a Digital Zone System that I've been working on.  

What I wanted to prove was that once I'd set up an input correction curve for each camera I own that the result would match the output of my other cameras, each with their own unique input correction curve.

The cameras I own span recent digital sensor development and manufacturing.  For this validation I chose two different formats, two different megapixel counts, and three different years sensor implementations.

In each case I spot metered the light area to Zone 7 and let the shadows fall where they will.  I did this because in digital I meter for the highlights and process for the shadows.  Keeping in mind, of course, this is the exact opposite of what we do with film.

Here's what I see ->

 

 

To my eyes this is an excellent match. Each input correction curve accurately matches the 1EV step as described by the original Zone System and adapted here to digital.

So here's a little game.  Want to win a free beer?  Tell me which camera made which image.

For me that's an easy bet for the house.  I seriously doubt anyone will be able to pass this test.  In fact, it's rather irrelevant.  Though it does make the point that if we understand our tools and set up our processing environments correctly, manufacturer to manufacturer variations, sensor to sensor variations, and generation to generation developments can all be "leveled" to the point good image making doesn't depend on tools as much as some would have us believe.

Digital Zone System ~ 0EV as Zone 5 RawTherapee processing example

The prior Digital Zone System posts laid the foundation for actual image processing.  I now share an example of processing a 0EV as Zone 5.

Simplifications ~

I don't want to spend my time metering using a spot meter.  Instead, I let the in-camera matrix metering system do its "thang" as I feel its more than "good enough" for the kinds of scenarios I find myself in.  Using the in-camera spot-meter is always an option in those cases where I feel it would be of benefit to meter more carefully.

0EV as Zone 5 input correction curves work well for 95% of my work.  Scenes tend to be flatly lit.  Often whites slide down the tonal scale and blacks crawl up, which means the tones I want to manage are all on the linear portion of the curve.

-1EV as Zone 5 input correction curves work well for me in high contrast situations, such as brightly lit, strong contrast situations.  In those cases (around 5% of my personal work) I see a benefit for expanding tonal separation in the light areas.  Certainly I can shoot everything at -1EV and process accordingly, but this really isn't necessary (see prior paragraph).  Besides, as ISO rises, so can noise in the shadow areas. 

I put as many settings tuned the way I want into the input correction curve recipe that I've saved from my calculations as possible.  These include Capture Sharpen, vignetting the edges, auto-lens correction, luminance exposure curves, luminosity black and white conversion, and a Camera Profile that interacts well with the luminosity conversion for maximum tonal separation in a single action.

RawTherapee 0EV as Zone 5 Image Processing ~

Opening an Image

 

Essential Elements -

• AMaZE de-mosaic used for low ISO images
• LMMSE de-mosaic is selected for ISO > +/- 1000 (depending on the sensor)
   

Applying Input Correction Tone Curve

Essential Elements -

• Luminosity Black and White conversion
• Luminance exposure curves 1 and 2
• Auto-lens Correction
• Capture Sharpen
• Vignetting the edges to taste
• Camera Profile with "Tone Curve" disabled 

Note: For my work I like Sony Standard and Vivid Camera Profiles.  In concert with Luminosity Black and White conversion they give additional tonal separation, this time in the color dimension (where the Digital Zone System is applying tonal separation in the exposure dimension).

Setting Black and White Curve Points

Essential Elements -

• Watching the histogram to verify where pure white and black is in the image, move Tone Curve 2's end points
• Upper right edge of the curve is white
• Lower left edge of the curve is black

In this example I see by examining the histogram in the upper left corner of the display that the highlights are correctly expressed. So all I needed to do was move the bottom left corner of Tone Curve 2 slightly to the right to get the blacks to turn pure black (again, see the histogram in the above image).

Note:  I realize many software do not offer a second Tone Curve.  In those cases it might be worth exploring other tone tools.  There should be tools with sliders for setting the black and white points.  I don't want to disturb the carefully constructed input correction curve.

Rotation, Cropping and Vignetting

Essential Elements -

• Align the verticals/horizontals to taste by rotating the image (where necessary)
• Crop the image to taste (since I tend to crop in-camera I often just shoot at 4:3 and call it good)
• An overall Vignette is already set in my input correction curve recipe, but...
• Now is a good time for me to dodge/burn or add vignette (as I've done to the bottom of the image in this example)

Adding a Pt/Pd Tone

Essential Elements -

•  I've found I enjoy the tints and tones of Pt/Pd images and have created and stored as recipes a number of tints that I can select from
  

Output Image

Essential Elements -

• For the "internets" is downsize the original image, and...
• I often ask the software sharpen the output once more
  

With relatively few inputs I'm able to generate a rather pleasing image (to me, at least).  Every tone is properly expressed.  Nothing is "blocked up."  The light areas positively "glow." 

Digital Zone System (Part Six) ~ Resources and Inspiration

I'm concerned that I've missed something or that I've misunderstood things.  Are there errors in my own thinking and methods?  No doubt.  If readers would like to help me better understand, I'm all ears.

Resources ~

Other than a ton of YouTube videos that erroneously describe how to meter for the Zone System in digital, there are few resources on the internets (again, thank ewe George Bush the Younger). 

Alan Ross Photography:  Can the Zone System Go Digital?

Photography Cheat Sheet: Using the Zone System for Ideal Exposures

Zone VI workshop - the fine print by Fred Picker - One of the most important Zone System references from the film era 

Zone System Manual by Minor White - This is the reference I used.  There's an "eye match" method for setting up the Zone System with film that I found to be very useful. Unfortunately the link to this is just a sample, so if you're interested you'll have to find a used book somewhere.

Another look at the Zone System (film and early digital)

I started a conversation on Pixls.us on the topic.

On Zone System evolution - Zone 9 was pure white early on, and later was changed to Zone 10?  I never knew this and am left wondering why the change?

What I've decribed as a Digital Zone System is not without its dissenters. There is a well-known commenter on camera gear who said -

"For me, it means forget the Zone System when you’re using digital cameras, except as a way to describe tones. Compared to the tools available on modern cameras, it’s crude and in accurate..."

Take from it what you will.

Inspiration ~

When I recently restarted work on a Digital Zone System my earlier life came flooding back.  

I was heavily influenced by Ansel Adams and Minor White for what they had to say about the technical aspects of the film-based Zone System.  I used a Pentax 1degree Spotmeter and calibrated my films and processing to the best of my abilities.  I read through Fred Pickers book on the Zone System, too.  Every photography exhibition I could find in the LA Basin saw my shadow on its doorstep.  Looking at what was possible in expressing a final image impressed me greatly. 

Here are just a few photographers who's works can inspire me, even today.

• Alan Ross ~ assistant to Ansel Adams
• Bruce Barnbaum
• Carl Weese 
• Chris Rainier
• John Sexton ~ assistant to Ansel Adams
• Paul Caponigro 
• Ray McSavaney ~ I wish I'd known of him earlier
• Tillman Crane

 

Bugatti Royale
Sony A6300, Sigma 30mm f/2.8 EX DN
-1EV as Zone 5
Pt/Pd tints added in processing

Digital Zone System (Part Five) ~ Tonal Separation In Three Ways

The Digital Zone System that I've written about here on my blog is just one aspect of controlling tonal separation in black and white digital photography.  

There are two other areas of control that I will now take into consideration.  Taken in total, these controls allow for much greater flexibility and ease in monochrome image creation than us old film workers could ever have imagined.

Here are three areas of tonal separation.

• Digital Zone System ~ tonal separation by exposure value
• Luminosity Black and White Conversion ~ tonal separation by Human Perception Modeling
• Color Contrast Management ~ usually thought of as filtration for color separation (as we did when shooting with B&W film)
  

Digital Zone System ~

As I've already covered in depth methods for controlling the Digital Zone System, I'd like to stress just one thing.  Even though I've written a lot about using -1EV as Zone 5, I've found that generating an input correction curve for 0EV as Zone 5 can yield excellent results.  Not the least of which can be a measured improvement in all the work I've done over the years before coming to the realization of the benefits of shooting -1EV as Zone 5.

Luminosity Black and White Conversion ~

While I've written about the benefits of performing a RawTherapee Luminosity black and white conversion, I believe it's worth revisiting the subject in light of the Digital Zone System.

First, I never use simple desaturation.  As readers will recall, Human Perception Modeling shows how viewers of black and white images see the tones of red, green, blue differently.  Desaturation makes the tones of equal energy colors the exact same tones of gray.  I don't want that.

Luminosity conversion from digital color into monochrome takes into account how humans see red, green, and blue.  In short, Luminosity conversion when combined with the Digital Zone System gives us a further improvement in tonal separation. 

Second, there is a color management detail that applies directly to tonal separation in black and white work. In Camera Profile there are several  selections. One is "Tone Curve" and two others are "Base Table" and "Look."  "Base Table" and "Look" manage colors.

With the Digital Zone System I disable "Tone Curve" because I insert control over the exposure value tonal range by applying an input correction curve.

Enabling either a standard or vivid Camera Profile and enabling "Base Table" and "Look" corrects colors at the post-demosaic stage.  This is important.  The process now becomes:

• Apply input correction curve
• Specify a standard or vivid (for increased color contrast) Camera Profile
• Disable "Tone Curve"
• Enable "Base Table"
• Enable "Look"

• Select Luminosity black and white conversion

We now have tonal separation in two flexible, controllable, and measurable dimensions.

Color Contrast Management ~

Now that we have tonal separation manged two ways, Digital Zone System and Luminosity Human Perception Modeling, we can add a third.

Using the Channel Mixer we can approximate filters used in black and white film work.  For instance, we can use a red filter to deepen blues, yellow filters to lighten greens, and blue-green filters to approximate the color spectrum response of Orthochromatic and wet-plate collodion.  Further, there is sufficient flexibility in the Channel Mixer that we can create any filter we want.

The use of these tools is less measurable and more "intuitive."  We can change settings until we like what we see. 

Taken in total, we now have tonal separation in three flexible, and controllable dimensions.

 

Sony A6000, Sigma 19mm f/2.8 EX DN
-1EV as Zone 5 Digital Zone System
Pt/Pd tints applied in processing

Digital Zone System (Part Four) ~ Concise Guide to the Entire Imaging Pipeline

Using the Digital Zone System input correction curve generated in Part Three, Here is a high level overview of the entire imaging pipeline.  Remembering that RAW files are essential in this process for retaining tonal values:

Metering ~

Easy Peasy Approach

• Let the in-camera matrix metering system do its job

Note: I've found this is good enough for me in 99percent of the cases I encounter.  The metering system knows how to balance tonal distribution quite nicely.

Intentional Approach

• Using the in-camera "Spot" meter, place tonal values 

Note: Taking time to spot meter a scene can yield accurate exposures per a photographers intentions.  This can work well with stationary subjects, or working in an environment where the lighting is stable (unchanging). 

Exposure ~

0EV as Zone 5

• Release the shutter

-1EV as Zone 5

• Set the exposure system to -1EV
• Release the shutter 

 Note: I've found I can work quickly and efficiently when under-exposing at -1EV and combining it with the Easy-Peasy Metering Approach.

Processing ~ 

• Import RAW image into a software for processing
• Apply the Digital Zone System corrective curve (created in Part Three)
• Watching how tones are distributed in the histogram
• Move the top of the curve to just above pure white
• Move the bottom of the curve to just below pure black
  
• Using normal image processing tools, modify contrast and brightness to taste

Note: RawTherapee comes with minimally four curves.  Two are found under the Exposure tab.  Two more are found under the Black and White controls.  Working with just the Exposure tab, the input correction curve will be found as Curve 1.  Using Curve 2 (also set to Luminance), setting the pure white and pure black values is a very simple exercise of moving the Curve 2 top and bottom points.

 

Sony A6000, Sigma 19mm f/2.8 EX DN
-1EV as Zone 5
Matrix metering
RawTherapee processed per above
Pt/Pd tints

Digital Zone System (Part Three) ~ Concise Guide to 1EV per Zone Curve Generation

[Updated 7 October, 2024 ~ Important correction: Zone 5 at 0EV is 76hex/118decimal, not 7F/127 as I previously wrote.]

Finally, coming to the meat of the matter, for this, Part Three, of my Concise Guide to the Digital Zone System, I present a method for taking a newly opened RAW file and generating a correction curve that gives exactly 1EV per Zone steps from +3EV (pure white in digital work) down as far as the sensor can differentiate (-7EV or -8EV in the case of my Sony APS-C and Full Frame cameras).

Definitions ~

• Using Luminance curves only (other curves will distort the color space which can impact the final result)
• Zone 5 remains 76(hexidecimal)/118(decimal) or "18% middle gray"
• Digital Zone System Zone -2 (which doesn't exist in the film Zone System) through Zone 8 are separated by 1EV (1 f-stop for us Old Farts) per Zone

Assumptions ~

• The old film-based Zone System is adaptable to digital B&W imaging
  
• The vast majority of digital B&W output looks different from film because of digital highlight attenuation
• "Camera Profile" normally tries to adjust 0EV to 76(hexidecimal)/118(decimal) on all three channels (RGB) or something thereabouts, depending on the "look."

 

Zone 5 as 0EV ~ attenuated highlights/unbalanced "digital" Zone System  ~

Taking the EV step RAW files from Part Two...

• Use "Curves" to raise/lower each individual EV image to match the hexadecimal/decimal values indicated below
• Raise/Lower the point where the curve overlaps the narrow tone spike seen in the histogram
• Build up an overall correction curve by adding points at each EV
• Saving curve corrections as you proceed through the list (see the example below) 
  
• Once you've corrected each EV to it's respective Zone tonality value, look at the overall curve and "smooth" it by gently adjusting up/down/sideways any value that is out of line 

• Zone -2 = 02(hexadecimal)/02(decimal) -7EV
• Zone -1 = 04(hexadecimal)/04(decimal) -6EV 
• Zone 0 = 08(hexadecimal)/08(decimal) -5EV 
• Zone 1 = 11(hexadecimal)/17(decimal) -4EV 
• Zone 2 = 1B(hexadecimal)/27(decimal) -3EV 
• Zone 3 = 28(hexadecimal)/40(decimal) -2EV 
• Zone 4 = 53(hexadecimal)/83(decimal) -1EV 
• Zone 5 = 76(hexadecimal)/118(decimal) -0EV 
• Zone 6 = AD(hexadecimal)/173(decimal) +1EV 
• Zone 7 = CB(hexadecimal)/203(decimal) +2EV 
• Zone 8 = F5(hexadecimal)/245(decimal) +3EV 
• Zone 9 = FF(hexadecimal)/256(decimal) +4EV

The correction curve could look like the following, depending on where you apply the correction curve (ie: before or after applying a "Camera Profile") 

Curve that defines
Zone 9 as pure white

Zone 5 as -1EV ~ balanced "film-like for digital" Zone System ~

Again, taking the EV step RAW files from the Part Two...

• Use "Curves" to raise/lower each individual EV image to match the hexadecimal/decimal values indicated below
• Raise/Lower the point where the curve overlaps the narrow tone spike seen in the histogram
• Build up the overall curve by adding points at each EV
• Saving curve corrections as you proceed through the list (see the example below)  
  
• Once you've corrected each EV to it's respective Zone tonality value, look at the overall curve and "smooth" it by gently adjusting up/down/sideways any value that is out of line

• Zone -2 = 02(hexadecimal)/02(decimal) -7EV
  
• Zone -1 = 04(hexadecimal)/04(decimal) -7EV
• Zone 0 = 08(hexadecimal)/08(decimal) -6EV 
• Zone 1 = 11(hexadecimal)/17(decimal) -5EV 
• Zone 2 = 1B(hexadecimal)/27(decimal) -4EV 
• Zone 3 = 28(hexadecimal)/40(decimal) -3EV 
• Zone 4 = 53(hexadecimal)/83(decimal) -2EV 
• Zone 5 = 76(hexadecimal)/118(decimal) -1EV 
• Zone 6 = A0(hexadecimal)/160(decimal) -0EV 
• Zone 7 = D9(hexadecimal)/217(decimal) +1EV 
• Zone 8 = E6(hexadecimal)/230(decimal) +2EV 
• Zone 9 = F5(hexadecimal)/245(decimal) +3EV 
• Zone 10 = FF(hexadecimal)/256(decimal) +4EV

The correction curve could look like the following, depending on where you apply the correction curve (ie: before or after applying a "Camera Profile") 

Curve that defines
Zone 10 as pure white

Original Assumptions ~

• Successfully demonstrated (I hope) - The old film-based Zone System is adaptable to digital B&W imaging
  
• A corrective solution is found - metering accordingly, set -1EV tones to Zone 5 value - The vast majority of digital B&W output looks different from film because of highlight compression
• Again, a corrective solution is found - metering accordingly, set -1EV tones to Zone 5 value - "Camera Profile" normally tries to adjust 0EV to 76(hexidecimal)/118(decimal) on all three channels (RGB) or something thereabouts, depending on the "look."

Digital Zone System (Part Two) ~ Concise Guide to System Characterization

[Updated 7 October, 2024 ~ Important correction: Zone 5 at 0EV is 76hex/118decimal, not 7F/127 as I previously wrote.]

None of this Zone System stuff is magic.  Hopefully what I write about is easily understandable, easily duplicated and quickly adapted by interested parties. 

In this, Part Two, I will present a process for understanding camera/software interactions at the very front end of the RAW image processing pipeline.  It sets the foundation for something that leads directly to Part Three. There, I will present a simple process for generating an accurate Digital Zone System tone curve tailored to systems interactions between camera sensors and software.

Definitions ~

• Using Luminance curves only (other curves will distort the color space which can impact the final result)
• Zone 5 remains 76(hexidecimal)/118(decimal) or "18% middle gray"
• Digital Zone System Zones 0 through 8 are separated by 1EV (1 f-stop for us Old Farts) per Zone

Assumptions ~

• The old film-based Zone System is adaptable to digital B&W imaging
  
• The vast majority of digital B&W output looks different from film because of highlight compression
• "Camera Profile" normally tries to adjust 0EV to 76(hexidecimal)/118(decimal) on all three channels (RGB) or something thereabouts, depending on the "look."

Building a Sensor/Software Step-Wedge ~

To understand how B&W tones are distributed at the start point for image processing, here is a method that I've found instructive.

Image creation ~

• Photographing a continuous tone scene (ie: blank wall, or blank sheet of paper)
• Setting the focal point well before or well behind the subject (to even out any textural/tonal variations of the blank subject)
  
• Shooting RAW
• Set ISO to lowest non-synthetic value (some camera systems allow for low and/or high ISO settings that "massage" RAW information, which we want to avoid for this procedure)
  
• Set the meter to "Spot" (to avoid problems of uneven field illumination, ie: lens vignetting)
  
  NOTE: I've found it easiest to set a camera on a tripod for this work to introduce as few lighting variables as possible
  
  
• Make an exposure at 0EV
• Increase exposure 1EV
• Make an exposure
  
• repeat this step to +4EV
  
• Make an exposure at -1EV
• Decrease Exposure by -1EV
• Make an exposure
  
• repeat this step down to -7EV or -8EV
  

Image processing ~

• Load RAW files into image processing software
• Convert to B&W (I use Luminance B&W conversion for its human perception properties)
  
• For each image...
  
• Mouse over the center of the image (where the Spot meter read the scene) 
• Note the Luminance value
  

After carefully noting the values from -7EV/-8EV through +4EV, you should have something that looks like the following.

In the example above I used a Sony A6300, Sigma 24mm f/3.5 DG DN focused to infinity, and photographed a blank white board.  It's easy to see that 0EV is _not_ 76(hexidecimal)/118(decimal).  That, in fact, is one of the roles of "Camera Profiles" when it applies a Tone Curve.

I'm exerting control over tonal values as early as possible in the process.  RawTherapee allows users to re-define the "Camera Profile" step.  In Part Three I will share how I define a new "Camera Profile" tailored to Digital Zone System work. I'm not aware of any other image processing software that allows for this kind of early intervention and I'll try to remember to describe the advantages of this in a future post.

As far as I understand the current State of Things, all other software use pre-defined "Camera Profiles" to get a RAW file to the point of image processing as quickly as possible.  What I present here in Part Two should be usable in all cases.  If what you see more closely matches the Digital Zone System synthetic step-wedge "out of the box", you're likely "good to go", within certain limits, such as accepting Zone 9 as pure white and associated highlight attenuation.

An interesting aside: The old Film Zone System described an 11EV or 11 f-stops of dynamic range.  From the above we can see that in Sony APS-C and before any further intervention that I have 12EV or 12 f-stops of dynamic range.

All this aside, the important point of this Part Two exercise is to understand how close we are to the old Film Zone System 1EV per Zone step ideal.

Digital Zone System (Part One) ~ Concise Guide to Step Wedge simulation

[Updated 7 October, 2024 ~ Important correction: Zone 5 at 0EV is 76hex/118decimal, not 7F/127 as I previously wrote.  The step wedge illustration has been updated as well]

There are no secrets to any of this, but I realize I moved rather quickly through a lot of material in my rush to understanding digital sensitometery and developing a decent black and white Digital Zone System solution.  Working in three parts, I will now try to show how anyone can do what I've done and make sure they, too, can achieve accurate results.  

This, part one, presents a recipe for generating a synthesized step-wedge.  Part two will present a process for understanding camera/software interactions which will lead directly to part three where I present a simple process for generating an accurate Digital Zone System tone curve tailored to cameras and image processing software.

Definitions ~

• Working toward a solution for black and white imaging (I may deal with color in the future)
  
• Using Luminance curves only (other curves will distort the color space which can impact the final result)
• Zone 5 shall be 76(hexidecimal)/118(decimal) or "middle gray"
  

Assumptions ~

• Digital Zone System Zones 0 through 8 are separated by 1EV per Zone
  
• "Camera Profile" normally tries to adjust 0EV to 76(hexidecimal)/118(decimal) on all three channels (RGB) or something thereabouts, depending on the "look."
  

Building a Synthetic Step-Wedge ~

Using an image processing software ->

• Create an image filled with 76(hexidecimal)/118(decimal) tone value
• Increase Exposure 1EV
• Note the new tone value
• repeat this step until you've found pure white - FF(hexidecimal)/256(decimal)
• Restart this process using the image filled with 76(hexidecimal)/118(decimal) tone value
• Decrease Exposure 1EV
• Note the new tone value
• repeat this step until you've found pure black - 00(hexidecimal)/0(decimal)

Carefully noting the values from -7EV through +4EV, as in the following.

 

Zone 5 as 0EV and -1EV
set to
#76/118decimal luminance value

Noting the decimal equivalent value in the event the image processing software uses that system (such as in RawTherapee), where the Gimp reports values in hexadecimal.

• 02(hexadecimal)/02(decimal) -7EV
• 04(hexadecimal)/04(decimal) -6EV 
• 08(hexadecimal)/08(decimal) -5EV 
• 11(hexadecimal)/17(decimal) -4EV 
• 1B(hexadecimal)/27(decimal) -3EV 
• 28(hexadecimal)/40(decimal) -2EV 
• 3A(hexadecimal)/58(decimal) -1EV 
• 76(hexadecimal)/118(decimal) -0EV 
• AD(hexadecimal)/173(decimal) +1EV 
• DC(hexadecimal)/220(decimal) +2EV  <- Corrected 22/06/2025
• F5(hexadecimal)/245(decimal) +3EV 
• FF(hexadecimal)/256(decimal) +4EV

 

Zone 5 as 0EV and -1EV
set to
#76/118decimal luminance value

We will work with these values in part three.  

For the moment, note the difference where +4EV is pure white in digital work, and remembering +5EV is pure white in film work.  We will also use this knowledge in part three.  

Also note that exact 1EV tonal separation exceeds the original film Zone System definition by providing potentially usable information down through -7EV, or Zone -2.  This will "work" if the camera/sensor/software systems allow.

Digital Sensitometry for Black and White ~ Automation ~ RAW and In-Camera jpg image processing

[Updated 7 October, 2024 ~ Important correction: Zone 5 at 0EV is 76hex/118decimal, not 7F/127 as I previously wrote.]

It's taken more than a few blog posts to get here.  At long last I come to the  question I had that launched this little digital sensitométrie adventure.

Original question: Is it possible to generate a decent black and white image in-camera?

Using the Zone System as a framework of understanding, from here on out the answer to this question should be quick and relatively easy.   So I'll dispense with my usual background/setup hoo-haa and get down to it.

RAW automation ~ 

Adobe Standard camera profile

I have to admit that manually controlling RawTherapee can be a bit scary.  There are so many options, so many tools, and so many operations to choose from.  Which is why it might be useful to look at an automation in the form of a camera profile to see how far down the Zone System road I can get on RAW file import.

Using the baseline Zone 5 as 0EV luminance reference, I took a look at Adobe Camera Standard .dcp. In RawTherapee I enabled Tone Curve, Base Table, and Look and looked at just the luminance channel.

Advantages -

• Easy to load a .dcp file into RawTherapee or Photoshop (where I'm sure it comes with the system as well as in Adobe's ACR tool)
• Pre-defines a usable tone curve
• Uses 0EV as Zone 5 so no "unusual" exposure compensation normally required
• Tames +1EV to +4EV light area transitions 
• Expresses more than 11EV dynamic range
  
• Input correction curves easily constructed to Zone System references
• Working from RAW allows greater flexibility in extreme image processing
  

Disadvantages -

• Black and white conversion required
• -0.3EV underexposure might help meet the idealized step wedge reference (see how the Adobe Standard curve is to the left of the reference)
  
• Zone 9 at +4EV remains the pure white saturation point (not Zone 10, +5EV as described by the original Zone System)
  

In-camera automation ~ using the jpg engine ~ 

Sony Creative Style Light

Flying by the seat of my pants and using years of experience printing black and white images I found that Sony's in-camera jpgs generated using Creative Style Light looked pretty good when I downloaded images and simply desaturated them off-camera.  

So it didn't surprise me when I measured the luminance curves using settings of Contrast -2, and Saturation -1 that the idealized Zone System step wedge is matched by desaturated Creative Style Light.

Advantages -

• Exactly matches idealized Zone System step wedge
  
• Expresses 11EV dynamic range
• Uses 0EV as Zone 5 so no "unusual" exposure compensation normally required
• RAW+jpg function available 
• Could be a good solution for posting converted black and white images when outside of Big Computer range (ie: while on the road) where I could have color (if I like Light colors) and monochrome jpgs
  

Disadvantages -

• Black and white conversion required
• Zone 9 at +4EV remains the pure white saturation point (not Zone 10, +5EV as described by the original Zone System)

Sony Picture Profile ~ Cine 4, Black and White

Sony camera features have evolved to include configurable video tone and color controls. The tool can be used for stills photography as well.

I found that Gamma Cine 4 raises the midtones. Setting Color Mode to Black and White performs a full black and white conversion in-camera.

Advantages -

• Delivers in-camera generated jpg that addresses the original question
• Configurable for a variety of parameters that can match idealized Zone System step wedge where users can configure ->
  
• Knee to define highlight roll-off characteristics
• Black Gamma to define the point of pure black
• Color Depth to build in-camera B&W filters thru RGBCMY channel controls - which I find to be an excellent feature
  
• Detail to control image sharpness
  
• Expresses 11EV dynamic range
• Uses 0EV as Zone 5 so no "unusual" exposure compensation normally required, though...
  
• RAW+jpg function available  
• Could be a good solution for posting black and white images when outside of Big Computer range (ie: while on the road) 

Disadvantages -

• Limited legacy camera support ~ Picture Profiles are available on certain Sony cameras beginning with A6300, A7S, A7II, and A7RII
• In practice, underexposure of -0.5EV or -0.3EV might be useful (see how the curve is to the left of the idealized step wedge)
  
• Camera exposure bracketing functions are not available
• Shooting while camera in Silent Mode not available
  
• Best used configured before a shoot - menu diving to change settings might be annoying during actual photography
  
• Tones in Pure White (which might relate to a video standard)
• Zone 9 at +4EV remains the pure white saturation point (not Zone 10, +5EV as described by the original Zone System)

Creative Style Black and White, contrast = 0

Turning to Sony's Creative Style Black and White, I first looked at how this style behaves at its default settings.

Advantages -

• Delivers in-camera generated jpg that addresses the original question
• Uses 0EV as Zone 5 so no "unusual" exposure compensation normally required
• Exposure bracketing functions available 
• RAW+jpg function available 
  

Disadvantages -

• Zone 5 to Zone 0 are darker than the idealized step wedge standard (which is here I saw problems in my own work)
  
• Expresses 10EV dynamic range
• Zone 9 at +4EV remains the pure white saturation point (not Zone 10, +5EV as described by the original Zone System)

Creative Style Black and White, contrast =-3

On a lark I thought I'd try Sony's Creative Style Black and White with the contrast turned down to the minimum -3.  Surprise! This simple setting seems to do the trick.  The dark regions under Zone 5 shift to the left to move up the exposure scale which correctly "opens up" the shadows.

Advantages -

• Delivers in-camera generated jpg that addresses the original question
• Expresses 11EV dynamic range 
• Uses 0EV as Zone 5 so no "unusual" exposure compensation normally required
• Exposure bracketing functions available 
• RAW+jpg function available
• Could be a good solution for posting black and white images when outside of Big Computer range (ie: while on the road) 
  

Disadvantages -

• Zone 9 at +4EV remains the pure white saturation point (not Zone 10, +5EV as described by the original Zone System)

I'm no longer flying by the seat of my pants when it comes to black and white photography and I believe I've adequately answered the original question.

--------- Where am I on my checklist of perceived "needs"? ---------------

Is what I'm doing here in trying to transfer old film-based Zone System knowledge into something practicable for digital...

• Measurable - Yes
• Accurate - Yes
  
• Repeatable - Yes
• Controllable - Yes
• Clearly understandable - Yes, but readers can judge otherwise if they like
  
• Reveals what Sony's in-camera jpg processor is doing - Yes
  
• Helps me choose a set of in-camera jpg engine operations and/or settings that match my RAW output - Yes, with certain perhaps narrow/small limitations
  
• Huge Bonus: I now have a linear Zone System digital match to the old idealized film-based Zone System for both RAW and jpg files.
  

Note: What I'm sharing in this series is limited to my experience with Sony full frame and APS-C mirrorless cameras and the sensors they come with.  In truth I have zero idea how other digital systems map tones, though I'm developing my own suspicions.  I hope the descriptions of what I'm doing here helps interested parties sort this out for their situations.  If not, let me know and I might lend a hand.