Chromatic aberration in 35mm Summicron M APO

[Derbyshire Man]

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I didn’t have to spend time scrutinising, it bopped me on the nose the first time the sun came out and I shot in colour!

Removed in seconds in post however. 

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[patrickcolpron]

On 10/26/2025 at 12:22 PM, Derbyshire Man said:

Just to reply with the full facts its a crop of an M11 image with the summicron m 35 apo

I never experienced this with an APO 35 but then again I seldom close any lenses down past f/5.6 and never crop my images to avoid these types of issues. 

The images seem odd to me. 

I would love to see the original raw file on my own computer to better answer this topic. 

[don daniel]

The shown images are heavily overexposed. What do you expect? 

[Derbyshire Man]

9 hours ago, don daniel said:

The shown images are heavily overexposed. What do you expect? 

They're not. As I said in the post these are contrejour shots so there are going to be bright areas, just going back to check the RGB values are up in the 99% range but not clipped. Here's the full file.

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[don daniel]

I cannot explain the purple fringing here. I own the Apo-Summicron 35mm. Fringing seems too strong here. I never stop down to f16, only to f8 or f11, when I want a longer shutter speed  on a tripod. But you shot at f4, too. And there it should be almost perfect.

[patrickcolpron]

It is one of those topic where I scratch my head for a couple of reasons:

One, I never encountered fringing, green or purple, or any chromatic aberration with my APO 35 which I've had about 3 to 6 months after its initial release. It is not a perfect lens, yet it is much better in this regards than any other Leica M lens. Whereas the APO 50 does suffer from fringing the APO 35 does not* 

Two, why would anyone make photos at f/16 with such a focal length, knowing it is a wide focal length. The depth of field at the distance the subject are in the sample images is quite "large". There no need to close down pass f/8 for any reasons that I can see. 

Three, anything at f/11 and smaller and you start introducing lens diffraction. Everyone who doesn't know about lens diffraction or what is lens diffraction, should both read up on the topic and test it for themselves.

I never use any lens closed down more than f/11. Even then, I seldom do it and it is usually when shooting high iso film (400 and up) with an analog M on a sunny day.

With a digital M I seldom go smaller than f/5.6 using iso 400 and 1/3000s on a sunny day. I may call iso 400 high but that is my go to standard with both digital and film cameras. Just that an analog M is limited to 1/1000s.  

Because images are worth a thousand words... 

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My youngest a few years back, straight into the sun at f/2 because I wanted to isolate him

A crop of the area of focus, that bright blob above the tree is the sun.

Now that I am pixel peeping, I do notice a slight purple fringing* on the lawn mower steering wheel highlight under my son's arm. I have to eat my words and say, yes it does fringe.. a smidge, but so little that it is inconsequential to my photography.

When looking at the whole image it is not something I even noticed before today, it is barely visible unless I zoom in on it. 

This is also why I would have liked to see the original raw file of the shown photos in the topic, before conversion, to open it on my own computer, maybe I missed (*no, no, I did miss...) something about this lens. 

Anyhoo, one of those "I will not go out of my way" to make a photo trying to replicate the issue encountered by @Derbyshire Man, since in my photography I never noticed it before today, while trying to show, a 'what the heck are you talking about' with one of my own sample image shot in high contrast straight into the sun and... Huh, oops, yikes! 

All in all, I stand corrected, the APO 35 does suffer from purple fringing. Yet, now that I finally noticed it, it is so minimal that I am not going to lose sleep over it. 

*I did only notice the APO 35 fringing when I inserted the crop image in this reply while typing this.

 

Edited Tuesday at 12:46 PM by patrickcolpron
Word of the day, "Oops" 

[BJohn]

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On 10/26/2025 at 11:49 AM, UliWer said:

I think the examples don‘t show chromatical aberrations but purple fringing. Both are often mixed up even though they have totally different causes: the first results from optical faults of the lens, the second from the sensor. You may find an explanation here:

https://www.imatest.com/docs/sfr_chromatic/

He is right, depends on the microlens design and I feel that the more MP we have, the more purple fringing can be created. Light basically can "overflow" and depends very much on resolution of the lens and sensor design. It is not often very easy to distinguish between both CA and PF. But as an example:

On 10/27/2025 at 2:49 AM, Kiwimac said:

The 28 f1.4 Summilux is often portrayed as being a purple fringing monster. 

I see it more pronounced on the M11P in comparison to the M10. As it doesn't go away with stopping the lens down, I feel confirmed that it is, due to the scenery, exposure but in the end coming in from the sensor design. I was also able to produce these PF depending on the photograph with the APO 50, even stopped down. And I highly believe that CA in general is very limited by design of that lens.

[Derbyshire Man]

Plot twist. Looking at the images I had a feeling that for landscape in colour it wasn't any more detailed at f2 than the Summilux, which didn't feel right.

I then busted out the Visoflex 2 and did some comparisons.

First OVF F2 (I've no idea if there's enough detail in these small files but I'll give it a go)

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[Derbyshire Man]

Next EVF f2

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[Derbyshire Man]

And finally EVF at f4 (I'm going to need to do screen shots by the look of it!)

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[Derbyshire Man]

Crops; OVF F2

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[Derbyshire Man]

EVF F2

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[Derbyshire Man]

So there's an additional focus issue. Looking at OVF vs EVF it back focusses on my two colour bodies but is perfect on the M11M.

The rest of the lenses however (summilux 35, 28, CV 90 2.8) are good on the colour bodies although tending to front focus (except the CV which is plumb on) the summilux 50 and 24 are not with me currently so I can't test. I haven't bothered so far to compare the pre-asph at 2.8 or Rocker 40.

[Derbyshire Man]

Worth noting that the screenshots don't do it justice, the resolution when actually focussed with the visoflex is astounding.

[UliWer]

I am not sure what you want to show with your examples.

Though whatever it is, if you want to do comparisons there is no other way than putting the camera on a tripod and making sure that you have exactly the same frame and your crops show exactly the same parts of your frame. 

[lct]

I would wait when the sun is behind the tree to get some contre-jour effect. No problem with the Summicron 35/2 v1 here.

[Derbyshire Man]

1 hour ago, Derbyshire Man said:

Worth noting that the screenshots don't do it justice, the resolution when actually focussed with the visoflex is astounding.

essentially the lens is back focussing. It's impossible to get a screen grab to come across and I should have saved a crop but it's super clear on the screen and in testing that up close on my colour bodies at 1m only the very nearest portion of the target could be considered at all in focus and the vast majority behind. 

What I don't know yet is whether that exacerbated or improved the high contrast purple fringing.

[Vanillasludge]

1 hour ago, lct said:

I would wait when the sun is behind the tree to get some contre-jour effect. No problem with the Summicron 35/2 v1 here.

Incredible, isn’t it?  Mine never ceases to amaze me.  

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[Vanillasludge]

1 hour ago, Derbyshire Man said:

essentially the lens is back focussing. It's impossible to get a screen grab to come across and I should have saved a crop but it's super clear on the screen and in testing that up close on my colour bodies at 1m only the very nearest portion of the target could be considered at all in focus and the vast majority behind. 

What I don't know yet is whether that exacerbated or improved the high contrast purple fringing.

Not to highjack this but to respond to LCT's post...Yes, there are some lenses that don't show chroma errors, and V1 35 F2 seems to be one...Of course, it's not going to have the maximum resolution of the APO, but for photographic purposes, it's pretty darned amazing.

Here's a crop from an M240 shot at F3.5 (Approx, as the goggles on my V1 hose up the aperture estimates). All sharpening turned off.

 

 

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Edited Wednesday at 12:47 AM by Vanillasludge

[Bikie John]

11 hours ago, Derbyshire Man said:

essentially the lens is back focussing. It's impossible to get a screen grab to come across and I should have saved a crop but it's super clear on the screen and in testing that up close on my colour bodies at 1m only the very nearest portion of the target could be considered at all in focus and the vast majority behind. 

What I don't know yet is whether that exacerbated or improved the high contrast purple fringing.

My understanding, from reading similar threads here rather than personal experience, is that fringing is worse, potentially a lot worse, when the subject is not in focus. The APO bit is excellent for the plane of focus but there are no guarantees  away from that and sometimes APO designs are worse than more traditional ones. So since you have discovered a focussing incompatibility that may well explain your fringing issues.

Time for an EV-1? 😁

John