Apo-Telyt 135mm f/3.4 ... chromatic aberration

[Nitnaros]

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went to the Leica store and put the 135mm/f3.4 on my M11 for a mini-test drive
focusing seems doable, hit rate via Visoflex2 of course a bit better

what surprised me - color aberration: here a shot wide open f/3.4:

first 100% crop - showing the green and purple fringing
then the full picture

I am a bit taken back by the amount of aberration as this is not a very demanding scene contrast wise (like backlit tree branches)

am I expecting too much?

 

 

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[a.noctilux]

15 minutes ago, Nitnaros said:

am I expecting too much?

I think so.

APO is not free of optical aberrations

APO correction ( for 3 or more colors falling on one plane) is only available for one plane.

If you are parallel with the text, you will get APO rendering.

Try it.

...

Going further, have a look at this other infamous first Apo-Telyt 3.4/180mm

noting the Delta for different light lengths, 400nm-700nm = 40nm which big pixels count can make it big and quite visible.

http://www.marcocavina.com/articoli_fotografici/Leitz_Apo-Telyt_180mm_glass/00_pag.htm

 

Edited August 19, 2023 by a.noctilux

[Nitnaros]

17 minutes ago, a.noctilux said:

APO correction ( for 3 or more colors falling on one plane) is only available for one plane.

 

ah, that is very helpful to know, I was not aware of that

I still need to do some research whether earlier versions of the 135mm lens would not give me more or less the same optical performance...

the current Apo-Telyt is very expensive for my use case scenario (landscape tele shots during hiking)

bye, Peter

[a.noctilux]

If you want to try 135mm lens for M,

I'm quite happy with Tele-Elmar 4/135 (which is "almost" as good as 3.4/135 ) a bit heavier.

For "better" ( = f/2.8) light catering, I use the Elmarit-M 2.8/135 which happend to have built-in (= for M finder) magnifier x1.5.

Heavy beast.

For EVF use, the Leitz R 2.8/135 almost as heavy, or why not the first APO lens 3.4/180, long but not too heavy and still first class for far objects.

Edited August 19, 2023 by a.noctilux

[spydrxx]

I'll second the 135/4 Tele-Elmar. which I've owned several different times, although I've settled on the older 135/4 Elmar, both for digital and film. In my experience some chromatic aberration can be significantly reduced in post processing, or by flipping color images to B&W. 

[Nitnaros]

Yep, the Tele-Elmar’s have stellar reviews

do they hold up to the M11’s 60 megapixels, though? 

[Ecar]

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+1 for the Tele-Elmar.

Regarding a sensor out-resolving a lens, there's no such thing. It's been discussed many times in this (and other) forum(s). An example:

 

[Kl@usW.]

vor 9 Stunden schrieb Nitnaros:

went to the Leica store and put the 135mm/f3.4 on my M11 for a mini-test drive
focusing seems doable, hit rate via Visoflex2 of course a bit better

what surprised me - color aberration: here a shot wide open f/3.4:

first 100% crop - showing the green and purple fringing
then the full picture

I am a bit taken back by the amount of aberration as this is not a very demanding scene contrast wise (like backlit tree branches)

am I expecting too much?

 

 

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Nitnaros, that's not a chromatic aberration, but a "creative font"you took a picture of. I own an Apo-Telyt and can positively tell you that I have never seen anything like the thing you show us. Btw; chromatic abberation looks different:  Longitudinal  chromatic aberration ( typical for  tele lenses ) will produce colored seams in oof areas.  The "normal" CA ( typical in normal or wide lenses) will produce colored seams in the sharp areas, as you mentioned eg. branches. But it is only a color lining, never a change of color of a whole  area as in your sample. 

K. 

 

[Gobert]

23 minutes ago, Kl@usW. said:

Nitnaros, that's not a chromatic aberration, but a "creative font"you took a picture of. I own an Apo-Telyt and can positively tell you that I have never seen anything like the thing you show us. Btw; chromatic abberation looks different:  Longitudinal  chromatic aberration ( typical for  tele lenses ) will produce colored seams in oof areas.  The "normal" CA ( typical in normal or wide lenses) will produce colored seams in the sharp areas, as you mentioned eg. branches. But it is only a color lining, never a change of color of a whole  area as in your sample. 

K. 

 

I don’t recognise it either. But I have an M10R for color photography. May be that’s the reason why.

[RexGig0]

The Flying Solo store, at 420 West Broadway, where you seem to have taken that shot, uses interesting colors, including magenta-to-blue, as part of its decorative theme. It is possible that you may have seen uniformly-colored lettering, but that that store’s color scheme reflected from the lettering, to be “seen” by the camera’s sensor. Just a guess, on my part. I am thinking of the effect of a fair-skinned person, among green vegetation, appearing to have green skin, in the captured image. Another possibility is that the lettering you photographed may have actually been a faded magenta-to-cyan, but may have appeared white, to your eyes, in the sunlight.

Edited to add: I found this store by running a search on the text of the lettering in the OP’s image. This store is in the same building as the Leica Store Soho in NYC. I grabbed this image from the web.

 

Edited August 20, 2023 by jaapv
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[adan]

16 hours ago, Nitnaros said:

I still need to do some research whether earlier versions of the 135mm lens would not give me more or less the same optical performance...

The Tele-Elmar - given its 59-year-old design - is very very good. A bit of "real" CA at f/4 (tiny red rims around fine details/lines that are in focus, for example). At f/5.6-8, almost indistinguishable from the APO, except for slightly lower "clarity." Same details, just a bit less obviously defined.

For me, the advantages of the APO-Telyt are: 50-100g lighter than the TE variants (or any Leica-M 135 since 1964), and almost a full stop greater brightness (T-stop - an effective T/3.0) due to more modern coatings and thinner glass elements, on top of the rated half-stop-larger f/3.4 aperture. And it comes with 6-bit coding (or can be retrofitted, for the pre-2014 versions)

Disadvantages: price; quite a bit of flare propensity with bright lights just outside the image area (internal reflections in the lens barrel behind the rear element - poor baffling); very sharp drop-off in sharpness if even slightly mis-focused (typical of the APO teles); combined with a short, touchy focus throw (breathe hard on the focus ring, and it can move enough to be noticably "off"  ).

The TE's residual spherical aberration (center of lens focuses very slightly in a different plane that the edges of the lens), produces a little bit of natural "focus stacking" wide-open, providing more leeway for "pretty sharp" images even if the focus is slightly off. Combined with the slightly smaller aperture (f/4.0) and longer vernier-precision focus throw (180°+), that can make a difference sometimes.

I actually own both, and swap them out based on expected practical needs of a given shoot. Weight, brightness/light available, whether I want more "relaxed" focusing, whether I want to use a different uncoded lens in place of the TE (50mm from the 1970s, 15mm from Voigtländer), how much other gear I will be carrying, etc. etc. Life is good.  

Edited August 20, 2023 by adan

[Nitnaros]

7 hours ago, RexGig0 said:

The Flying Solo store, at 420 West Broadway, where you seem to have taken that shot

 

The pic has been taken in Vienna/Austria; the sign has no coloration at all. 
 

so whether this is CA or not, it’s an artifact of the telyt/M11 pic 

[lct]

54 minutes ago, Nitnaros said:

[...] whether this is CA or not, it’s an artifact of the telyt/M11 pic

CA or not, looks like color fringing indeed. No apo lens i've experience with is totally free from that, especially in case of over-exposure, and fringings are not necessarily thin like in the snap below with Summicron 50/2 apo. Now i have got significant fringings with neither Apo-Telyt 135/3.4 nor Tele-Elmar 135/4 so far. I did not test the Apo-Telyt on the M11 though TBH. Will do it when time allows.

https://photos.smugmug.com/photos/i-N6bgfZh/0/a9c791a7/X4/i-N6bgfZh-X4.jpg

Edited August 20, 2023 by lct

[adan]

Explanation of Nitnaros' experimental results from the APO-Telyt 135mm.

Below is a diagram of how an apochromatic lens works. It focuses three colors/wavelengths/frequencies of light together at (and only at) the plane of focus (f). Producing no fringing in that exact plane (and only in that exact plane). 

Note what happens in the "out of focus" planes/areas to the left and right of plane f.

The colored light rays are not only not focused there, they are not even parallel. They s p r e a d  o u t, in spectral or reverse-spectral order. Just like rainbows (and double-rainbows), or Newton's glass-prism experiments.

And that produces visible color fringes (regardless of exposure or any other factor) in the background and foreground blurs.

And the speading is inverted on either side of the plane of focus (background blur and foregorund blur). To the left the order is red-green-blue; on the right the order is blue-green-red.

Which is why the fringes in the sample photo are magenta in the foreground blur, and green in the background blur - complementary colors. (I presume that as visual artists, we all know what complementary colors are.  Color-wheel class 101).

If one hopes that any "APO" or apochromatic lens will magically show no color fringing anywhere (including the de-focused areas), I am afraid one will have to move to a different Universe, with different laws of physics.  

(image linked from Wikimedia Commons)

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[lct]

Thank you @adan. Fact is that some lenses are more prone to color fringing than others though and it happens more often at large apertures than at smaller ones apparently. I can get more of it with a Summicron 90/2 apo at f/2 than with a Tele-Tessar 85/4 at f/4 for example. Would be interesting to know how the Apo-Telyt 135/3.4 compares with non apo lenses like Tele-Elmar 135/4 that does almost as well as the Tele-Tessar 85/4 in matter of CA.

[Nitnaros]

4 hours ago, adan said:

If one hopes that any "APO" or apochromatic lens will magically show no color fringing anywhere (including the de-focused areas), I am afraid one will have to move to a different Universe, with different laws of physics.

Hah, thank you, @adan, for that great explanation - that brings clarity and sets the right expectations … and I learned something 🙂 

I made this post since I was surprised to see that discoloration for what seemed to be a well behaved test target for a simplistic “focus test” (I focused on the “y” in “years”) 

bye, Peter 

 

[RexGig0]

Well, this has been a very interesting discussion. I had known about color fringing, but to see an “APO” lens display it quite so vividly has been a learning experience. Of course, “APO” is a marketing term, and some “APO” lenses are more apochromatic than others.

It is also interesting to see how typing the pictured sign’s words into a search engine lead me to a store located in NYC, that happens to be in the same building as a Leica Store, rather than the correct location in Vienna, Austria. Not that search engines are infallible, either, of course.

Edited August 20, 2023 by RexGig0

[Nitnaros]

@RexGig0 … hey, but that was a very creative search investigation you did !

[lct]

Purple and green fringes at f/3.4 with Apo-Telyt 135/3.4 on M11.
Typical CA i suppose but i have no clue about "loca" or "laca" things.
FF @ 1/1000s
crop @ 1/1000s
crop @ 1/500s
crop @ 1/250s

Edited August 20, 2023 by lct

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[BastianK]

Wow. So many things are being mixed up here.
The underlying problem is, that there is no lens police that will check a manufacturer's claim for an APO tag.
Meaning: any manufacturer can slap an APO tag on any of their lenses.

By my definition: if there is an APO tag I expect that there is no bokeh fringing (what we see in the opening post)
and also no purple fringing.
For some APO lenses this is actually the case (many Macro lenses, many Voigtländer APO lenses), for some it is not,
including this 135mm 3.4 (and also the Voigtländer VM 35mm 2.0 APO-Lanthar).

Would I expect in a 135mm 3.4 for that price that it is perfectly corrected? Hell yes.
After all, there are plenty of harder to design lenses that are cheaper and better corrected. 
Do I think the price tag for that lens is justified considering its performance? Not really.
 

Edited August 21, 2023 by BastianK