Saturday, April 20, 2024

What to do in late 2023 into 2024

Here's a list of potentially interesting/fun things to do around l'isle de France.

Art/History/Automobile Photography Opportunities

21-27 April - Tour Auto 2024 a la porte de Versailles, Parc des Expositions

1-12 May - Foire de Paris

11/12 May - Vintage Revival Montlhery 100 year celebration!

2-8 June - Rallye des Princesses 2024 (I won't be here for this)

23 June - Peking to Paris 2024 ends in Paris 

12-13 October - 100 year celebration Montlhery UTAC

Calendar of Montlhery events - 2024


-------------- DONE ---------------

17 March ~ Photo Foire ~ Chelles  ~ a GREAT show, but I didn't buy a thing

3 March ~ le carnival des femmes ~ depart pl. du Chatelet 14h30 (No Go)

24 February - 3 March ~ Salon International de l'Agriculture (No Go - way too many political issues)

11 February ~ Carnival de Paris ~ Promenade de Boeuf Gras ~ depart pl. Gambetta - No Go (wet, cold)

31 January - 4 February - Retromobile 2024  (Flickr

Ferrari ~ Retromobile ~ 2024

14 January - la traversee de Paris 2024 (Flickr

la traversee de Paris 2024

15 December 2023 ~ Noir et Blanc, BnF (Flickr

Bibliothèque nationale de France ~ 2023

6 December 2023 ~ Van Gogh - (Flickr)

1 December 2023 - Nicolas de Staël ~ City of Paris Museum of Modern Art (Flickr)

Musee d'Orsay ~ Paris 2021

30 November - 3 December ~ Salon des Vins des Vignerons Indépendants (Flickr

Salon des Vignerons Independents ~ 2023

November 2023 ~ Les halles Saint Pierre - Two shows (Flickr)

La Halle Saint-Pierre, Paris ~ 2023 


Musée international d'Art naïf Anatole Jakovsky

Ben Vautier

Thursday, April 11, 2024

Read the Readme, Dumb~Me...

Important Note to Self: Read the ReadMe file!!!

I've experienced a couple challenges recently when trying Fuji film simulations in RawTherapee. Things just weren't working out as expected.

For instance, when downloading cinema oriented Fuji-look-alike LUTs I learned to be very careful to find out if the LUT collection was made for S-Log input.  Why?  S-Log on the video side produces a very flat file for a very specific set of reasons that have nothing to do with stills photography.  And I'm not sure how to create an S-Log image starting from a stills RAW.

No matter how hard I tried, applying a S-Log LUT to a stills image seriously distorts the colors and contrast.  What drives me crazy is that none of the cine LUTs I tried come with a ReadMe file that might explain any of this.  Apparently I'm not one of the "cool kids" who can figure this out before downloading and attempting something.  So to make my life easier I've learned to avoid cine LUTs in general.

Further narrowing my search a little to camera profiles and LUTs developed for stills work I have belatedly learned that some of these files were specifically designed for use with "linear" camera profiles in RentWare.  The devil is in the details.  This is very important as some camera profiles and LUTs both add not only the color grading/film simulation, but they're also managing the initial tone curve as well.  

Once I understood that some LUTs require a "linear" camera profile starting point I was able to achieve the film simulation I was looking for.  It's correct to the point I doubt anyone would be able to tell which camera was used with the Fuji film simulation.  

When working in RawTherapee I create a "linear" camera profile by simply de-selecting "Tone Curve" in the Color Management module.  There is no need to load a specially made for RentWare "linear" camera profile into RawTherapee.

One more step is required.  To ensure the camera profiles color grading function does not influence the film simulation result I simply  de-select "Look Table" in the Color Management module as well.  

Here's a quick look at how de-selecting these two components in Color Management compare to the RawTherapee default color managed state -


Using Fuji film simulations in RawTherapee


Resources -

An excellent look at how Fuji film simulations modify colors - 

Individual Cluts can be downloaded off this site.  I've found that I can load a RAW image into RawTherapee, deselect "Tone Cuve" and "Look Table" in the Color Management module, and then apply these film simulations without further image manipulation (as in the above image).

Another Fuji HaldCLut package -

Note: When using these HaldCluts I've found I need to lighten the tones while keeping the Color Management "linear."  I do this by modifying "Exposure" or by sliding the top end of the tone curve to the left using "Luminosity."  Doing these things allows me to match the output of the above Clut collection.

Thursday, April 04, 2024

Summary ~ a comment I posted to

I realize that something I posted to works as a kind of Summary of Findings.  So I thought it might be interesting to share it here.

Retromobile ~ 2024

In addition to the many good comments, I’ll throw in my $0.02 worth. Keeping mind anything I say is worth the price you paid for it (ie: $0).

From looking at lenses for going on four decades to find a certain “magic”, here’s what I’ve learned.

    Until surprisingly recently, lens designers I’ve talked with felt that correcting for 7th order effects, while “do-able”, was a little over the top. People told me it was “unnecessary.” Modern optics can be corrected for 11th or, gasp, 13th order effects. There are a few interesting reasons to do this now.

    In general, vintage lenses typically were designed for either resolution or contrast. Modern optics can be found that strike an interesting balance between resolution and contrast (see previous paragraph). Which leads me to think the computing required to design lenses for 11th order effects was rather too great for rooms filled with human calculators (see Nikon’s 1000 and 1 Night series).

    In the vast majority of imaging systems I’ve looked at, resolution limitations are found in light sensitive materials (ie: film or digital sensor) and not in the lenses themselves when operating at their optimum aperture. OK. That’s a strong caveat, but someone sent me years ago a 75mm f/8 wide angle lens that covers at least 4x5 inches that is diffraction limited from wide open. So “softness” at wide apertures for some vintage optics is there because they’ve been designed this way.

    This is why I feel many vintage lens manufacturers designed their optics to a customer base (sort of). I’m thinking of old Nikon optics where they were designed for under-corrected spherical aberration behind the point of focus as well as providing a veiling spherical aberration wide open. This was, I’m convinced, deliberate to satisfy the Japanese market which valued a “delicacy” of rendition. Canon OTOH went the over way because of their customer base and over-corrected for spherical aberration behind the point of focus. Old Canon lenses can appear sharp wide open, but deliver nasty soap-bubble-ish background rendition as a result. Pentax, again in broad, designed their lenses to be more neutral.

    Modern Voighlander Heliar lenses bear little to zero rendition resemblance to lenses made for large format film in the early to mid 20th century. Which is to say, be careful of thinking naming conventions will render a scene similarly across the ages. Another example of what i mean is anything labeled “Sonnar.” How well a lens is corrected is more a function of careful design. Don’t believe me? Compare early Zeiss, mid-century Soviet, and the (justifiably) highly regarded 10.5cm/105mm Nikkor-P “Sonnar” designs. Out of focus rendition, chromatic aberration, flare, and astigmatism are treated widely differently depending on who designed the lens and is not something inherent in the basic optical layout. The Kingslake comments previously noted elsewhere in this thread about the Tessar formula being another excellent example. I’ve not encountered such a consistently horrid lens (and I’ve owned far too many of them) as the Zeiss 50mm f/3.5 or f/2.8 Tessar coming from the former Eastern Bloc. They blew it. It never gets “sharp”, really. f/8 seems the best it can do for an acceptable image.

    Modern optics can suffer from a surprising level of field distortion (barrel or pincushion). It appears to me that lens designers sometimes rely rather strongly on software to correct this kind of distortion since it makes it easier/cheaper to correct for chromatic aberration, astigmatism, and flare. In general, vintage lenses can be surprisingly “rectilinear” and I’ve not found it necessary to lean heavily on distortion corrections.

    Many vintage and most modern optics appear to offer pretty good field flatness. Zoom lenses can be another matter, particularly those designed for SLR and early DSLR. No, not all suffer from this, but I can pretty much find a weak spot in just about any zoom. There’s nearly always a “hole” somewhere in the zoom range, or so it seems.

    Even knowing all these things, trying to see an advantage of one thing over another can be difficult. I would enjoy buying a beer for the person who could sit down next to me and tell me which image was made with which lens. It’s impossible, of course. But because we’re on the “inside” and it matters to us, we often place a LOT of emphasis on the lenses we choose. I can’t tell the difference between images made with a new Sigma 24mm f/3.5 DG DN and an early '80’s Nikon Nikkor 24mm f/2.8 Ai. I could say similar things about just any of the lenses I own, vintage or modern.

So after all these years and all this thrashing and whinging and wrangling where did I find the “magic” I was looking for? I found it in careful image processing. This means tightly controlled color management, color grading, sharpness and local contrast controls, etc, etc, etc. This means being clear with myself on what I seek in and how to express a subject/scene in the final result.

OK. Enough of that. There’s much more I could say, but why? I’ve already said too much.

Tuesday, March 05, 2024

Capture Sharpen ~ Sony 55mm f/1.8, Nikon Nikkor 105mm f/2.5, Nikon Nikkor 135mm f/3.5 with 1.4x Sigma AF teleconverter

In a previous post I noted that a couple of Nikkors mated with a Sigma 1.4x AF teleconverter were softer than the nature lens sans Sigma.  This was conventional wisdom back in the day and is easily confirmed using modern cameras.

There are tools in this Digital Age, however, that were not available to us Old Dinosaurs of the Film Age.  Sone of them are image sharpeners.  In particular, something called "Capture Sharpen."  It is available in Adobe rentware as well as the Open Source RawTherapee and is used as a pre-sharpener before using something like "UnSharp Mask" or other sharpeners (of which there are many).

So thinking a little about the softening effects of the Sigma 1.4x teleconverter, I wondered what would happen if I "Capture Sharpened" the Nikkor images?  Just to see how it compared, I thought it might be interesting to see how the Sony Zeiss FE 55mm f/1.8 "Capture Sharpened", too.  And shoot everything at the soft-ish wide open aperture.

Here's what I found.


Capture Sharpen ~ Sony 55mm, Nikkor 105mm, Nikkor 135mm


The "Capture Sharpened" Nikkor/Sigma images are "sharper" than the un-sharpened Zony.  The Zony "Capture Sharpened" is, well, over the top amazing.  Wide open.

Voila the Miracle of Modern Image Processing tools.

Friday, March 01, 2024

Nikon Nikkor 135mm f/2.8 AiS, Nikon Nikkor 105mm f/2.5 K, Sony 55mm f/1.8 ZA, Sigma 1.4x teleconverter ~ Considering Old Lens Magic

Roundy-round I go, yet again, one more time, perhaps with a bit more feeling, and a bit more bravado.

I can't remember how many Nikkor 135mm lenses I've bought and sold over the years.  Usually I'll pick something up for a project, finish the project, then sell the lens after it's sat in the Toy Closet for what I consider too long.  Mainly as a source of funding for Yet Another Project.

Some time back there was Yet Another Project that came up and while I had some wonderful lenses at the time that might fit most of the purpose, there was a gap in my focal length lineup.  Indeed, you probably could guess the missing focal length.  That's right.  135mm.

Browsing the local on-line ads I contacted several people and considered several different lenses.  Should I go really cheap and spend around 25Euro?  Most of the lenses in this price class were either 3rd party (Vivitar, Soligor, etc) or had some kind of fault, like fungus or non-operable apertures. Or should I go a little higher end and spend over 100Euro?  Zeiss and Nikon and Leitz were typically the ones people felt were made of gold and set their asking prices accordingly.

The items I could view depended on my search criteria.  So I typically try all manner of combinations just to see what pops up.  This is how I found a lens located just down the street from me for a nicely small-ish well less than 100Euro price.

Once home I checked the serial number of the lens to see when it was manufactured.  I thought I was looking at a Nikon Nikkor 135mm f/2.8 Ai.  But this was wrong.  It's actually a late model AiS version c.2003.

The focus systems changed between the Ai and AiS Nikkor series.  The AiS lenses focus more quickly with shorter throws than the Ai.  In this case I've read that the Ai 135mm is around 270degrees stop to stop, where the AiS is around 170degrees.  My concern with the AiS was that focusing action would be too quick and that I could easily mis-focus.  If that is the only downside, I'd have to learn to be careful with focusing during the project that I had in mind.

I'd also read various comments around the 'net where folks didn't like their 135mm Nikkors and preferred the 105mm f/2.5.  Most of the comments were about how the 135mm was less sharp than the 105mm.  Since I had both focal lengths I thought it might be interesting to find out how my optics compared.

To set a baseline I used a Sony FE 55mm f/1.8 ZA (Zeiss) as a reference.  Then I remembered that I have a Sigma 1.4x AF teleconverter and wondered how that might effect performance of the Nikkors.  I figured I'd add the teleconverter to the comparison since I hauled it out of the Toy Box while scrounging for something else.  The 105 and 135 are short enough in physical length that maybe I could use them in the field with a bit more reach that the Sigma 1.4x would provide.

Here's what I found.  Remember to click on the following image and enlarge to 100% to see whatever there is to see.


Comparison ~ Nikkor 105mm, Nikkor 135mm, Sony 55mm ZA


Comments - 

Well... well... well...  Can I tell any meaningful difference between Zony 55mm and Nikkors?  Nope.  

Are there any differences between the Nikkors themselves?  Nope.  

I suppose, in terms of "sharpness" the Nikkors feel "fatter" in image rendition than the Zony, but how the heck do I measure something like that?  

OK.  Maybe the Nikkors are a 1/64th of a step behind the Zony.  Maybe.  But probably not.  They're all equal.  Really.

What about when I add a Sigma 1.4x AF teleconverter into the Nikkor mix?  Contrast is lower and there's a slight loss of resolution in the center of the field.  The corners look awful.

Just to check as much as I could check and to cross as many bridges as I could, I re-ran the comparison using the 135mm f/2.8 with the Sigma 1.4x, focusing first in the center of the field, taking a photo, then focusing at the outer edges, and taking another photo.  

The results speak for themselves.  The teleconverter appears to introduce field curvature.  Since I can't measure how badly the field is curved, I'm not yet sure how it will impact image-making in the field.  What I know is to avoid photographing flat subjects using this combination.  But it might be just fine for photographing motorcycles at speed on a racetrack where the edges of the scene count for nothing but blur and color.

In the end I really can't tell much difference in terms of "sharpness" between the Zony and Nikkor lenses.  I'm convinced that any differences would come down to my camera-craft and abilities to control my camera-work. Putting a stake in the heart of "sharpness" concerns and in the case of the two lenses I own the AiS 135mm f/2.8  is every bit the equal to the legendary 105mm Xenotar Nikkor.

Friday, February 16, 2024

True Focal Length ~ Sony 35mm f/2.8 ZA, Sigma 24mm f/3.5 DG DN, Tamron 20mm f/2.8 Di III

Casually reading something on the internet, I stumbled across a comment about how the field of view narrows when applying lens corrections to the Tamron 20mm f/2.8 Di III.  The writer claimed the lens went from 20mm uncorrected to 22mm corrected.


Bugatti ~ Retromobile ~ 2024

Image taken using at
Tamron 20mm f/2.8 Di III


I instantly thought that a gap from 24mm to 22mm might not be worth the effort to carry two lenses, the Tamron 20mm and a Sigma 24mm f/3.5 DG DN.

I've caught myself out in the past in reading something, not fully understanding the situation, selling a lens or camera, only to find out later that I was wrong and that the "problem" I was trying to solve was actually something completely different.

Case in point: There was a wonderfully sharp little Sigma 60mm f/2.8 DN EX E that suddenly developed a problem focusing.  I read on the internet that the AF mechanism was not up to snuff, so I sold the optic.  Only to find out a few weeks later that there was some grease stuck around the AF circuit on the shutter release of my Sony A6000.  I cleaned the A6000 and instantly everything was good again and the AF worked correctly.  All was not lost, however.  I picked up a brand new Sony 50mm f/1.8 SEL OSS that has proven to be great jewel-like little lens.  Still, I learned something from the experience.

Thinking that the Tamron corrected and Sigma lenses were too close together in focal length, my first impulse was to sell the 20mm Tamron and buy a Sigma 17mm f/4 DG DN or a Sigma 20mm f/2 DG DN.

But hold the horses.  Maybe I should check the actual focal lengths of these and then make a better informed decision.

Taking a ruler, I measured 1100mm from the tripod mounted camera to a spot on the floor where I stretched the ruler parallel to the film plane of the camera.  Then I took a photo using three lenses, the Tamron 20mm f/2.8 Di III, the Sigma 24mm f/3.5 DG DN, and the Sony 35mm f/2.8 ZA.  

I then noted the numbers on the ruler in the horizontal direction at the very edges of the scene uncorrected and then corrected, calculated the base of the isosceles triangle, calculated the angle at the film plane of the camera, then calculated the actual focal length of the lens at 1100mm distance from the subject.  Easy peasey.  Right.  Here's what I found.

Tamron 20mm f/2.8 Di III uncorrected - 18mm

Tamron 20mm f/2.8 Di III corrected - 21mm

Sigma 24mm f/3.5 DG DN uncorrected - 27mm

Sigma 24mm f/3.5 DG DN corrected - 27mm

Sony 35mm f/2.8 ZA uncorrected - 39mm

Sony 35mm f/2.8 ZA corrected - 39mm

Well, lookee there, will ya?  

The Sigma and Sony lenses have longer focal lengths than marked when focused on a subject 1100mm away.  I would have expected that with an old manual focus lenses were the entire lens group moved forward when focused on close subjects.  Extending the lens distance to the image plane increases focal length.  But since the Sony and Sigma are internally focusing lenses, I thought there might be a lot less of what cinematographers call "focus breathing."  That's where the size of a subject changes with changes in focus.

OK.  So I learned that the Sigma and Sony lenses are longer than expected.  

What about the Tamron?  It starts wider than marked on the front of the lens when uncorrected.  The lens suffers from a large amount of barrel distortion and I can see quite a shift around the edges when a correction is applied.  Once applied, the lens measures 21mm.  This is much closer to what is marked on the lens than either the Sigma or the Sony.

A gap from 21mm to 27mm between two lenses is actually quite enough for me.  I don't feel the need to find something different.  Buying and selling lenses is becoming a chore and is something of a thrash, so I'll stick with what I have for now.  I'm glad I checked.

Saturday, February 10, 2024

RawTherapee dcp and lcp files...

I need to remember something detailed.


Retromobile ~ 2024


In using RawTherapee to process RAW files I've found it has sophisticated color and lens management systems.

Interestingly, RawTherapee accepts industry standard dcp and lcp files.  dcp files are for color management and lcp are for lens corrections.

Rawtherapee comes with some dcp and lcp files on installation which appear to be updated from time to time.  I'm not sure who generates these files, but they seem to have done a good job for the lenses and camera models covered by the software distribution.

However, I found some of my cameras (Sony NEX, A6000, A5000, A7) and lenses (Sigma 24mm and a few others) are not supported by RawTherapee automation for the version I'm running (the latest), so I set off in search of good dcp and lcp files to fill in the gaps.

It turns out a certain RentWare implements these two file formats for their own color and lens management systems.  I wondered if I might be able to borrow them?  I run Linux, but have a computer that can boot into Windoze.  Here's what I do.

Boot into Windoze and...

  • In a browser search for "Adobe Camera Raw download" and locate the Adobe site (there are other sites that may offer downloads, but they are highly suspicious and I avoid them like the plague)
  • Download the latest "Camera Raw" plugin (I do not want LR or PS, just the RAW converter part)
  • Execute the "...exe" file to unpack the plugin
  • Descend the "c:\ProgramData\Adobe..." folder structure to locate "CameraProfiles" and "LensProfiles"
  • Copy the contents of these two folder structures into a Linux readable location/media

Boot into Linux and... 

  • Copy the "CameraProfiles" and "LensProfiles" directories and their contents somewhere under $HOME where I can easily find them
  • Open RawTherapee
  • Open an image and...
  • Under Color Management 
    • Select "custom"
    • Open the directory box
    • Locate the "camera profiles" directory
    • Descend the directory to...
    • Locate the camera model
  • Under "Profile Lens Correction" 
    • Select "LCP file"
    • Open the directory box
    • Locate the "lens profiles" directory
    • Descend the directory to...
    • Locate the right lens
  •  The base image is now configured using good dcp and lcp configurations.

Under "Lens corrections" there are selections for "Geometric distortion", "Vignetting", and "Chromatic aberration."  I turn off "Vignetting" because I've found that correction to be too strong for my taste.  But I do turn on "Geometric distortion" and "Chromatic aberration."

Under "Color management" there are selections for "Tone Curve", "Base Table", "Look Table", and "Baseline Exposure."  These are defined here.

On a practical level here's what I do.

  • Open an image in Rawtherapee
  • Let Rawtherapee select the demosaic algorithm (long topic for another time)
  • Set the lens profile
  • Select the color management dcp to be used (more on this in a moment)
  • Select "Tone Curve"
  • Select "Base Table" if selectable (this is not always implemented in some of the dcp files I've seen)
  • Select "Look Table" to get the dcp files color grading (which can be glorious, BTW)
  • Unselect "Baseline Exposure" since there is no jpg reference (read the definitions linked to above)

If I want to make further changes to "Curves", I go to the...

  • Eexposure panel
  • Find the curve function
  • Select "Luminance" 
  • _Then_ make adjustments to the curve
This keeps the colors from shifting.  Remembering, of course, that standard curves modify RGB curves at the same time the luminance curve is changed.  This modifies the color of the image, which I find I do not want to happen since  I like the "Look Table" results and do not want them to change.

From the list of practical things that I do I said I would comment further on selecting a <specific camera model> dcp.  The RentWare distribution is a little complex in how they've implemented their dcp directory structure.  Basically, it comes down to this.  Under "CameraProfiles" we have two ways of further descending the directory structure.

  • "...CameraProfiles/AdobeStandard/<specific camera model>.dcp"
  • "...CameraProfiles/Camera/<specific camera model>/<several dcp to choose from>

I'll start with the ".../Camera/<specific camera model>..." profiles.   From what I can tell these are the RentWares attempt to match specific image style selections offered by the manufacturer.  For instance, with the Sony A7 there are vivid, neutral, standard, landscape, and other dcp selections found in this directory.  If I want an image to look similar to the in-camera style selection, this is a good place to start.

Looking in AdobeStandard/... directory I see the RentWare has offered something a little different.  This is appears to be their own interpretation of what a "good image" would start with.  I find in the case of the Sony A7 that the ".../AdobeStandard/Sony ILCE-7 AdobeStandard.dcp"offers a more muted yellow, for instance, color starting point than the Camera/<specific camera model>/... "standard" dcp.  It pays to experiment and experience these various dcp options.

You notice that I've said nothing about using the RawTherapee "Processing Profiles."  This is because I've found the automated selections to be too strong for my quickly evolving image processing tastes.

OK.  There it is.  Lots and lots of detail.  But if I save a base processing configuration, the processing workflow can collapse to a single button push.  It's pretty sophisticated stuff, but I'm learning it's well worth the while to understand what's going on.