Correcting or exploiting Lens aberrations/character. What's you insight/experience?

In the current thread on Photographing the Interior of a Yacht, Leonardo mentioned built-in lens corrections for Mamiya lenses in Phase One RAW processing software. This is a good kick-off point for assembling our experience on this subject.

leonardobarreto.com said:

I can't wait to see the next version of C1 with lens correction filters specifically designed for Mamiya lenses,

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Use of technical details of optical design and shortcomings of each particular lens: That ability to recognize/specify lenses is already used by Leica with the M8 and Hasselblad with their H3. Obviously one can use DXO. I like the general trend to accounting for and correcting the lens design quirks and character.

Exploiting Lens Quirks or "Deficiencies" to advantage: Looking another way, think of how creative one can be with defocus of a "Lens Baby™" or see Jim Galli's super-sized and impressive B&W art using an old uncorrected Petzval design projector lens that doesn't even have a shutter, LOL! Think outside the box when you don't need to have orthogonal lines, uniform focus and straight lines!

Asher

Soft focus lenses and generally lenses with smooth rendering of out-of-focus areas (AKA "good bokeh") often have some undercorrected (or arguably properly corrected in some cases--as opposed to "overcorrected") spherical aberration. The Voigtlander Heliar (the original ones, not the modern lenses of the same name made by Cosina) is a good example of a lens that has just enough spherical aberration to be interesting. What this means is that the rays entering at the edge of the lens focus at a different point from where the rays enter the center of the lens, and the effect can be reduced or virtually eliminated by stopping down the lens. When it's used for creative effect, the sharp area is very sharp and the background is smooth and creamy, and there's can be an overlay of the diffuse image visible in the highlights of the sharp image. I suppose the best way to simulate this digitally would be to shoot with a wide aperture for short DOF, and then in post have a sharp image in one layer and a diffuse image in another layer and combine them to taste.

The Verito, which was one of the more interesting soft focus lenses from around the turn of the century through WWII, shows quite a lot of spherical aberration wide open through around f:8, and then one only sees the residual chromatic aberration if one looks closely. A strong monochromatic filter will eliminate chromatic aberration with panchromatic B&W films.

The Petzval, which is still used for projection, was a very successful portrait lens in the 19th century, because it was fast (around f:4) and reasonably sharp when used within limits. It gets those wacky effects when used for formats much larger than originally intended and closer to infinity than studio portrait distances. The "swirly" effect is from a combination of field curvature (the focal plane being more like the surface of a sphere than a plane) and coma (the spreading of points in the corners so they're rendered more like comets), and there's probably some chromatic aberration (which wouldn't have mattered in the days of orthochromatic plates) and spherical aberration going on there as well.

Jim Galli has posted a number of lens comparisons to see these different effects on his website.

Hi David,

Thanks for the insights. Which projector lenses should one go after for 8x10 and 4x5 format. They are often heavy and have no shutter of course! What would be your choices today and where do the Cooke projector lenses fit into this? Are they Petzvals too?

Asher

With projection lenses you're using them out of spec, so you have to experiment a bit and see what works. Old brass projection lenses are usually from magic lantern projectors, so they have a good chance of covering 4x5" with a little swirliness at the edges. 8x10" you might want to look for a real portrait Petzval.

The topic of swirliness came up regarding a 9" Verito I have listed for sale over at LFForum so I made these 2 portraits earlier today. This fits this discussion very well because it is a case where a certain phenomenon was sought and the lens, format and subject were combined to arrive at the ideal.


Pam is my sweet bride of a mere 32 years. 32 years was how long she wanted a doggie and her mean old husband said NO DOGS!

These were done on 8X10. The 9" Verito is taxed to cover 8X10 but that also contributes to the swirliness in the edges.

Hi Jim,

I do like both pictures. One can charge people like going on a merry-go-round. I got dizzy! That verito certainly adds something dynamic to the image.

Gee, this is the same focal length as my cooke PS945! These pictures have the advantage of a surreal experience! It seems that your wife and the dog have just appeared through a worm hole in time and space!

I can see how this lens is tamed considerable used on a 4x5 camera. Do you have an aperture on the lens and what happens if you stop it down more?

Asher

BTW, you can post BUY and Sell here too, if you wish! Since we have the same software vBulletin as LF forum, you can just copy the post exactly and it will appear here. We only have a modest group of LF guys here, but it would be enlightening for people to see what marvels little green men can find.

Just checking?

Hi Asher,

Did you mean to put this thread in Photography as Art?
I would of thought it would be better in an equipment or technique forum.

-Nat

Nathaniel Alpert said:

Hi Asher,

Did you mean to put this thread in Photography as Art?
I would of thought it would be better in an equipment or technique forum.

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Hi Nathaniel,

Yes, I did think about that too! However, I settled on this forum and this is why. Here we are using the lenses to write in a particular way, with individual characteristics like that of fine camel's hair brush versus something uniform like nylon or rough like horse hair. In this thread we are looking to recognize and discuss characteristics (of even what one might call imperfections of distortions) which can be exploited. The lenses might be a coke bottle or a $1 magnifying glass or else a fine Canon 85mm f 1.2.

Where could one discuss these? After all, one person might have a Fuji, the next a 4x5 camera and someone else a Canon 5D. So where would one file this?

Since we are not concerned with the brand of camera nor the format of camera or even film versus digital, just the artistic effects, then Photography as Art seems the best fit.

Asher

As we progress, the archaic separations by brand and format need to shrink anyway. We have to combine some equipment fora as they sometimes appear to emphasize differences which are not so important any more.

A tiny 96mm petzval that casts a complete circle within the confine of 4X5 sheet film. It would just cover the 6X7cm format.

That, Jim is one great shot. I think I'm going to plagarize, if I may and put a 90mm lens on my 8x10 camera.

Was that Petzval a projector lens? what make is it? This picture is very impressive. In one shot you combine a Wide Bodied jet plane, a Great trans-continental train and car with a face and teeth!

I am fascinated with how you find these bargains!

Asher

Asher Kelman said:

That, Jim is one great shot. I think I'm going to plagarize, if I may and put a 90mm lens on my 8x10 camera.

Was that Petzval a projector lens? what make is it? This picture is very impressive. In one shot you combine a Wide Bodied jet plane, a Great trans-continental train and car with a face and teeth!

I am fascinated with how you find these bargains!

Asher

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Asher, the equivalent on 8X10 would be about 7 1/2 - 8 inch. Yes, it was a little no-name projector lens that said made in france on it.



I did a little series with it, but the Nash was the best of them.

I think that the angle of view and distortion looks to me more like a much wider lens on an 8x10 than 7.5"! Mu 150mm Super Symmar XL does not give anything like that, but I have tried it on such a car! My 8x10 is in Chamonix Hospital until my new one arrives with a reduction back in the same color able to take Quickloads, ready loads and a Polaroid Holder!

Asher