Sunday, June 12, 2022

Specialty Lenses ~ a more personal history

Specialty "soft focus" lenses can be a real kick in the pants, but most of the time they are difficult to control.

I've owned many "soft focus" lenses.

It all started with a 12inch Portland lens that I dearly wish I'd kept.  I didn't use it much and I now very much regret selling that lens.  I paid next to nothing for it and got next to nothing selling it on.

I also owned a Wollensak Verito, but it never was mounted nor used.  Stupid, stupid, silly me.  What I'd give to have that lens back.  Like the Portland soft focus lens, I paid next to nothing for the Verito and got very little when I sold it.

There were three other large format soft focus lenses that passed through my toy box.  Two came from Fuji and were the 180mm and 250mm SF lenses.  Like the Verito and Portland optics I never came to grip with the Fujinon SF, even though I tried them many times.  Something simply did not "click" (ahem) for me.  Same for a gorgeous Rodenstock 300mm Imagon lens that came with a complete set of sieves.

The "soft focus" lens I had the most luck with was a Mamiya 150mm SF for RB67 that came with the sieve set.  I picked it up for cheap from KEH and used it on a workman-like Mamiya RZ.  I photographed some of my wife's roses and peonies with it.  I still have several palladium contact prints that I made from digital inter-negatives that I scanned from the original 120 6x7cm.  The prints "sing" to me.  The flowers "glow" so magnificently.   These prints remain something quite special.

I have a Pentax 85mm f/2.2 Soft that was originally in Pentax K mount, but came to me in Nikon F mount.  Talk about under-corrected spherical aberration behind the point of focus!  Eowza!! that thing is over the top.  

Even stopping the Pentax down it fails to sharpen up in any meaningful way.  It's simply too much for me and I'd prefer a bit more softness control.  It's probably too much for other people, too.  I've had this lens forsale on a local website for months and no one appears the least bit interested.  Can't say I blame them.

After trading emails with a scientist photographer who received his PhD in the topic of "pictorialist" lenses I learned something interesting.  Of course, now I'd like to find the lens he says modern day "pictorialists" swear by.  It's the Minolta Varisoft 85mm lens and hey cost the moon.  I doubt I'll ever find one for a reasonable living on a fixed income price.  Though I do keep my eyes open.

A couple years ago I picked up a box of lenses for 7Euro each.  One of them was a Nikon Nikkor 50mm f/2 Ai.  It was disassembled, cleaned up, and as it was being put back together, a thought occurred to me that maybe using the rear element set all by itself could be "interesting."  I found I needed to put a couple extension tubes in line to get the setup to focus from infinity down to something pretty close.  It did the trick.  Some of the photos I made with it weren't half bad.

Paris ~ Fall 2020

Paris ~ Fall 2020

Since hunting and gathering is a full time obsession for me, the 50mm f/2 Nikkor was sold.  In the process of moving to Nikkor 50mm f/1.4 manual focus lenses, I stumbled across a 20Euro beater Nikkor-S.C.  I got the parts off it I needed for another Nikkor-S.C. project and quickly realized I had a similar setup to my old Soft Focus Special.

Using an 11mm extension tube I found the Nikkor-S.C. 50mm f/1.4 rear element set Soft Focus Special could focus from infinity to about a foot.  This was a much shorter lens adaptation than the f/2 was.


Nikon Nikkor-S.C. 50mm f/1.4 without front element set

Nikon Nikkor-S.C. 50mm f/1.4 without front element set


Looking at how it renders I feel that it behaves rather similarly to the old Wollensak Varito.  There's swirl around the edges of the frame.  There's loads of barrel distortion (which I didn't find in this quantity in the converated 50mm H f2).  The under-corrected spherical aberration is controllable using the aperture.  To help protect the lens internals I mounted up an old UV filter.  In short, not a bad "find" out of a cheap ready for the recycler lens.


Nikon Nikkor-S.C. 50mm f1.4 without front element set

Nikon Nikkor-S.C. 50mm f1.4 without front element set

Nikon Nikkor-S.C. 50mm f1.4 without front element set

Nikon Nikkor-S.C. 50mm f1.4 without front element set


Nikon Nikkor-S.C. 50mm f/1.4 without front element set

Nikon Nikkor-S.C. 50mm f/1.4 without front element set


How does the rear element set of a classic old manual focus double Gauss design give a soft focus rendition?  Nikon's "Thousand and One Nights" history series may have the answer.  When designing wide aperture SLR lenses they would "fight fire with fire" by letting under-corrected spherical aberration dominate both element sets of deeply ground element curves.  The trick appears to be to balance that under-correction.  The first element set gives under-correction and the second element set inverts the effect and re-corrects it back out.

With this in mind, you can use either the front or aft element set from a double Gauss lens to achieve a similar effect.  In the case of my thrashed 50mm S.C. the fore element group has deep scratchs and boatloads of fungus, but the rear element set remains clear.  This, it turns out, matches the configuration of the old Portland soft focus lens that I dearly miss.  The aperture is in from the element(s) and controls the level of softness.

One thing I notice is the out of focus transition behind the point of focus is very very smooth from the "get-go."  Where most old under-corrected 50mm lenses transition through the out of focus disk having a bright center _and_ a somewhat bright outter ring, this Nikkor SF Special transitions straight to beautiful under-corrected spherical aberration behind the point of focus.  No outter ring around the out of focus disk.  It's glorious.

I don't like this kind of rendering for automobiles (though things look slightly better in Black and White than they do in color) or many of the man-made subjects around town. The effect, however, looks pretty good on vegetation and in portraiture.  It's a matter of finding a subject that, to one's eyes, is enhanced by the softness.

Friday, June 10, 2022

Lens Out of Focus Rendition ~ a more personal history

Out of focus rendition behind the point of focus is where the "character" of a lens is.

For years I thought optical resolution was where "magic" could be found in a lens.  It took me a couple decades to learn otherwise.  Sharp lenses aren't hard to make.  Everyone is capable of manufacturing lenses that are "sharp."

I've learned that, for me, it's other optical properties that make a lens interesting and adds "character" to an image.  This is what I'm talking about when I write about the out of focus rendition behind the point of focus.  There are three kinds of out of focus rendition and they are as follows.

  • Under-Corrected Spherical Aberration - the out of focus disk of highlights are lighter (show more energy) in the center of the disk than at the edge
  • Neutrally-Corrected Spherical Aberration - the out of focus disk of highlights are smooth and evenly illuminated across the disk
  • Over-Corrected Spherical Aberration - the out of focus disk of highlights show bright edges and are "hollow" in the center of the disk

NOTE: These effects are most often and most easily seen when a lens is shot wide open.

Nikon knows that under-corrected spherical aberration behind the point of focus can produce a "subtle", "delicate", and "beautiful" effect.  From what I see they've been designing lenses to build this into their lenses since at least the end of WWII. For their old manual focus lenses Nikon has a clear understanding of the effect.

Zeiss lenses tend to be designed for neutral spherical aberration corrections.  I have a gorgeous Sony Zeiss 16-70mm f/4 ZA OSS that appears to be been designed this way.  And I have a couple Nikon zoom lenses that behave this way, too.  One is the cheap and under-appreciated E-series 75-150mm f/3.5.  The other is the 100-300mm f/5.6 AiS which is also cheap and under-appreciated.  I find out of focus rendering to be wonderfully smooth.

Old manual focus over-corrected lenses tend to appear "sharper" at the point of focus than under-corrected lenses (where spherical aberration tends to veil an image).  I'm convinced this is why certain manufacturers chose this approach.  I'm thinking of the Zeiss 50mm f/3.5 and f/2.8 Tessar lenses and many of the Canon FL, FD, and FDn designs.  This effect is what people tend to call "soap bubble bokeh."  I don't like it, but I know of photographers who do.

Back when I shot large format film (4x5inch up through 12x20inches) I felt with no real evidence other than "Tribal Widsom" that German made lenses were the "best."  I owned a nice collection of Schneider, Voightlander, and Zeiss lenses.

It was only recently that I read about Nikon's lens design philosophy and how they applied their under-corrected spherical aberration approach to their medium and large format lenses, as well.

I saw "something" in the way a pretty little Nikkor-M 200m f/8 performed, but at the time I couldn't "put my finger" on what it was.  Well, looking at a few of my old negatives I now see it was this out of focus rendition that makes Nikkor optics so special.  It was a real missed opportunity for me to explore what the Nikkor-W series of lenses were capable of. 

How to know how a lens was designed for behind the point of focus rendition?

This is easy.  Very easy, in fact.  Using a digital camera with focus magnification -

  1) Mount a lens on a camera

  2) Find and focus on bright highlights

  3) Magnify a highlight to 15x

  4) Start to slowly turn the focus ring from farther away to closer

  5) Watch the highlights as they go out of focus, note the highlights in one of three following ways:

        a) Bright point in the center of the expanding luminous out of focus disk - this indicates under-corrected spherical aberration behind the point of focus.  Often with old lenses you will see what appears to be a brighter ring around the edges of the out of focus disks.  This is normal.  What's important is to see is that the center is brighter than the surrounding disk area (with the possible exception of the very edges of the disk).

        b) Luminous out of focus disk remains smooth across the field - this indicates a neutrally corrected optic (these tended, until recently, to be rather rare in my experience)

        c) Bright disk edges with hollow center - the out of focus disk looks like a doughnut - this indicates an over-correction leading to "soap bubble bokeh"

I do this when considering a lens I'm not already familiar with and this simple technique works a charm.

Modern mirrorless AF lenses from Sony, Nikon, and Olympus are designed to eliminate as many optical defects as possible.  With the aid of computer ray tracing software and improved manufacturing techniques many new lenses are darned near "perfect."  You can use the technique of verifying the out of focus rendition on current optics, too.

Wednesday, June 08, 2022

Lens "Sharpness" ~ a more personal history

In looking at lenses and cameras, in doing these tests and comparisons I've always taken the simplest, most direct approach possible.  No fancy, often very expensive, test and measurement gear.  Just a standard USAF military test chart, newspaper, or "interesting" subject, cameras, lenses, film, and, more recently, digital sensors, a lot of research, more than a few conversations with scientists, and a bit of experience.  

Anyone can duplicate what I've done.  Which is partly the point.  If there are any questions about what I've written, people can have a look for themselves to see what's true, correct, or not.

I thought perhaps was now the time to share and sum up a few things that I've learned over the past quarter century of poking and prodding.

Lenses, unless otherwise designed and with very few exceptions, are sharp. Period.

Fixed focal length lenses are sharp, at least.  Zoom lenses?  It's a bit more complicated.

I've been fortunate enough to have been able to enjoy a vast variety of lenses over the years.  How many hundreds and hundreds of lenses have I owned, tried, tested, compared, considered, shot with, and written about?  Everything from very large format film down through APS-C digital have spent time in my Closet of Goodies. 

In my youth I shot primarily 35mm.  A Pentax H1A was my very first "serious" camera.  Then came a Canon FTb QL, Pentax MX and MV, a Nikon FM, a Canon F1 (first of the series),  several Canon AE-1/AV-1/AE-1 Program, and two Leica M3.

I had access to a Mamiya C220 for some years as well.  It was a wonderful camera.

One year I had a tax rebate large enough to allow me to buy a new Sinar F with extension rail, and what turned out to be a very nice, borderline fabulous 210mm f/5.6 Schneider Symmar-S MC.  I owned that setup for many many years and have more than a few wonderful negatives from that setup.

In my early 35mm and 120 format days I didn't have many thoughts about optics.  I didn't know enough then to form an opinion and I wasn't curious enough to have a look.  All I wanted to do was "find some magic", shoot a few good photos, become famous, and lead the Life of Riley.  

After realizing the world wasn't exactly coming to my doorstep and that I needed to put my head down, apply some effort, and simply get to work, I became curious all kinds of thing, including looking at what was really going on with cameras and lenses and such.   The Sinar F 4x5, Schneider Symmar-S MC 210mm kit was the first to fed that curiosity.

It started with the aid of a USAF Resolution Test Chart back in 1998.  I shared some of my first test results with folks on-line in the then still the academic implementation of what would soon become the "internet".  Those were the days of UUnet, modems, newsgroups, and the East/West communications link that stretched between MIT and Tektronix.

Kerry Thalmann (an engineer from Intel) contacted me (I was working at Tektronix at the time) and suggested we look at a bunch of his lenses too.  The mossy rock was soon scooting unflappably down the hill.  Here I am 24 years later, still looking at photography things, asking questions, and generally poking around to see whatever there is to see.  

I quickly learned that old lenses could be as good as new while looking at a pair of turn of the century Protar lenses and compared them against something quite modern.  Yes, the modern lens looked very so slightly "sharper", but there was certainly nothing wrong with the Protar images.  It took extreme magnification to see any difference between lenses from the early and late 20th century.  This was an important learning for me because this was the first time I experienced something that would frequently ran counter to whatever marketing literature came my way.

Of course I found I preferred some lenses more than others.  Often it more than anything else came down to whichever lenses had the most reliable shutters.  Here is a list of Large Format Favorites.

  • Schneider Super Symmar XL 110mm f/5.6 on 4x5inch
  • Schneider Symmar-S MC 210mm f/5.6 on 4x5inch and 5x7inch
  • Kodak Commercial Ektar 300mm f/6.3 on 8x10inch
  • Kodak Wide Field Ektar 250mm f/6.7 on 7x17inch
  • Fuji Fujinon C 450mm f/12.5 on 12x20inch

I also found joy in shooting Schneider's "Angulon" series of optics, too.  They are small, light, and covered large pieces of film quite well.  Other small, light optics that were wonderful to use were the rare and difficult to find Zeiss Jena Germinar lenses.

My favorite medium format lenses were Schneider Xenotar on Rolleiflex TLRs.  They were slightly less sharp than the glorious Mamiya 7 optics, but they had contrast, those Schneiders did.  Why on Gawds Green Earth I ever sold those Rollei's?  Well, I couldn't bring them with me when we moved to Europe.  It was a simple as that.  So I sold them.

For a short time I owned a cosmetically pristine Hasselblad 500CM.  It was one of those classic "dream cameras" that seemed too often just out of reach financially.  I had a couple film backs, a 45 degree finder, 50mm, 80mm, 120mm, and 150mm Zeiss lenses.  I wanted to love the setup.  I really did.  But it spent as much time in the shop getting repaired as it did on a tripod getting used.

It was always the little niggling things.  In-body light-trap barn door springs were prone to bending.  The light-trap materials used on film backs were prone to leaking light after just a couple months of use.  The whole plot felt weak and under-engineered.  I'd learned how to replace the film-back light trap materials.  But after the camera body went to the shop for it's third light-trap spring replacement I was done.  No more.  It was more of a pain in the arse than it was worth.

Looking for a replacement to the recalcitrant Hasselblad led me to discover a wonderful Mamiya 7.  The 50mm, 80mm, and 150mm lenses were all demonstrably sharper than anything I'd ever "tested" at 120 line-pair per mm, baby! (which, BTW, was the absolute resolution limit of TMax 100 in D76).  The camera was light, handy, and gave a nice, large, useable 6x7cm negative.  Along with the Rolleis, I think that if I ever get back into film (which I never will) I'd sure like to have another Mamiya 7.

My arrival to the New Age of digital photography was at first a horror show.  

Canon EOS APS-C format lenses and 40D and 50D in-camera jpg processing were absolute cr*p.  Images are visibly soft.  Even now I can't believe just how bad some of that work was. I had to keep the final image sizes small to give the illusion of them being acceptable.  This is why at first I still hung on to my medium format cameras.

Convinced "better" lenses would do the trick, I sold the first couple of Canon optics and went with hugely expensive L-glass.

After seeing that even the L-glass looked "soft" under a wide variety of circumstances on a brand new Canon 5D MkII, I dug around the 'net and found an answer.  The in-camera jpg processor was junk.  Hence the switch to RAW, which helped, but wasn't the complete answer.

I learned that Canon sensors are "soft" due to the heavy AA filter they use over the sensor.  I could lean heavily on USM to get something semi-decent out of the 7D and 5D MkII RAW images.  I didn't know just how strong that AA filter is until, one day, I shot a 100-400mm f/4.5-5.6 Canon L adapted to Sony APS-C A6000.  It was like the clouds had parted and everything was now clear.  The difference was dramatic.

In the end, my Canon Drama of visibly soft image came down to three things.  Lenses were, in fact, just barely "good enough", but they weren't the primary source of my problems.  The in-camera jpg processor cranked out soft images... and... Canon's use of heavy AA filtering softened all output, RAW and JPG.

Recently I read Thom Hogan's comments on early zoom lenses being designed for adequacy, not optical perfection.  Here's what he said.

"...As film SLRs developed and gained in popularity, a number of things started to happen with optics. In particular, autofocus and zoom focal ranges added convenience that drove much of the designs in the 70's, 80's, and 90's. The original Tamron 28-200mm lens in the early 90's also started a trend that was much imitated: "good enough" across a wide range of things..."

Looking at this with nearly perfect 20/20 hindsight I have the strongest impression that Canon was doing everything just "good enough" but no better.  While I have no direct knowledge of this, M.Hogan indicates Canon's old design approach may still be in play here in the Mirrorless Age.

"...  It took Sony awhile to get on board, but Olympus and Nikon have done this from the beginning of their mirrorless endeavors: simply design better lenses. Far better lenses. Lenses with a near complete lack of negative attributes. Canon, unfortunately, seems to be going to take a while to get fully up to speed with this..." [the bold is my emphasis]

It bears repeating that Canon lenses for me looked substantially better when used on Sony cameras.  The jpg-processor and the strong AA filters of Canon cameras often masked optical performance.

Having moved on from Canon is probably the best thing I've done since switching to digital.  Really good Canon EOS to Sony E AF adapter performance was not at first to be found.  In frustration I sold all my L-glass.

As a consequence, I'm most familiar with Sigma and Sony lenses on crisp, clean, clear Sony sensor'd bodies.  In general I love them.  They are spectacular.  And, yes, I'm still very much in love with my old "filled with character when shot wide open" manual focus Nikon Nikkors.  There is lots for me to appreciate and enjoy on both old and new optics.

Lenses are seldom the determining factor in whether an image is "sharp" or not.   It turns out, film and sensors limit resolution.  Lenses most of the time just come along for the ride.

Monday, June 06, 2022

Current lens design technolgies paying off...

Thom Hogan has been around the block more than a few times and _really_ knows what he's talking about.

So when he writes about the current state of lens design technologies, it can pay to listen to him.

While I may in the end choose to stay with my old "charactered" SLR lenses on Full Frame Sony A7, I can fully appreciated what Thom writes about how good new lenses can be.  And for this I'm sorely tempted to sell off all the old stuff and go with the new.

Vintage Revival Montlhery ~ 2022