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noah_addis

Red Edge--Which lenses?

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I've been having the red edge problem with my M9 and coded 21 Elmarit Asph. It appears in nearly every frame.

 

I know there has been a lot of talk about this problem, so I wanted to start a thread to discuss which lenses exhibit this behavior and which do not. Let's avoid speculation about the cause and when/if we'll get a firmware fix for now.

 

Personally, I'm curious if the 24 Elmarit, 24 'Lux and 21 'Lux have a red-edge problem. But I think it would be helpful to have a list of which lenses work and which don't.

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Depends on the definition of red edge. If you look very close (LAB color picker, snow scene for example), I got a very slight red shift even with my Elmarit 28/2.8 Asph. Hardly visible, but it is there. The next firmware should finetune the color shift.

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On my 24 Lux I got no visible red edge, even on Snow - so, that does look good.

 

rdgs

 

JPH

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Hi Noah - I don't have all these lenses, but I am aware of which are supposed to be troublesome:

 

18mm SE,

21 elmarit asph,

24 elmarit asph,

28 elmarit asph (apparently this lens has the steepest angle of light of any of them).

I don't have any of these lenses, but I understand that they are the 'tricky' ones. I'm pretty sure that even with these it's

 

to a lesser extent:

28 'cron and

WATE (I have both of these lenses, and I don't think it's a significant issue with either).

 

I understand that the 21 and 24 lux lenses are okay, I haven't heard anything said about the 24mm elmar. (I don't have any of these lenses either).

 

I imagine this will be largely (if not completely) dealt with in firmware updates in the future, but of course, I can't be sure.

 

As far as non-leica lenses are concerned, I don't have a great deal of knowledge, but I think that most of the Zeiss and CV wides show the issue to a greater or lesser extent.

 

Worth pointing out here that Sandy's estimable Cornerfix program really does sort this problem out for the time being. You can get it here:

 

Link to Cornerfix

 

I hope this is helpful

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21 Elmarit pre-ASPH seems to be about the same as the ASPH version - red left edge about 5-8% of the frame. Also a slight blue edge to the right side.

 

35 'lux preASPH and 35 'cron ASPH - no red edge.

_________________________________________

 

BTW I have found another "fix" for red edges.

 

Adobe Camera Raw 5.6 (and I presume, Lightroom 5.6 (?)) now has a graduated-filter tool, and by using it in color mode with the color set to the appropriate complementary green-cyan tint, narrow graduated green-cyan fades can be applied to neutralize the red. On multiple edges, if needed.

 

And then saved as a preset that can be applied with one mouse click to any subsequent image.

 

Not as precise as CornerFix, no doubt - but it is "one-stop shopping" and doesn't require uncompressed .dngs

 

This sample is just a first approximation (I only discovered this yesterday) - I need to tweak the exact color density and gradation location. Red "bottom" since it is a vertical, with slight corrections also to the right side (reduce red) and top (reduce complementary blue with an orange grad filter). 21 Elmarit pre-ASPH.

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I checked and look at images that I took using the 21mm Elmarit ASPH more closely. I could see faint red corners rather than red edges. Maybe that's just more vignetting issue than real red edges in my case. After the vignetting adjustment, this issue seems to disappear almost completely. The images I examined are regular images and not test images of light colored and evenly lit images. And I do not have any snow images either. I am not saying that the problem doesn't exist, it is there in Andy's image, but the problem is not that noticeable, if at all, only under certain conditions.

 

I am using both Capture One 5.02 and LR 2.6. Maybe I am more imagining but it seems that CO seems to render the corners better (less reddish issue) than LR does. I switched between the two back and forth about 10 times to do the comparison. Is that possible that this problem is more accentuated by a certain RAW converter over the other?

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Andy, interesting workflow. Alas, my CS3 ACR has no color grad tool, and my RAW converter is CaptureOne. However, CS3 can do LAB color. I have a PS action that converts to LAB, adds a curves layer mask, and changes "a" and "b" curve. This preset can be fine tuned then with opacity and unmasking the corners. Cornerfix is often spot on, but sometimes the manual workflow is better

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I have the following wide lenses I use on the M9:

 

C/V 12mm- Left corner red edge. I correct it with Cornefix, It's really easy to do.

16-18-21mm Tri Elmar- No issue.

24mm Elmarit- No issue.

28mm Summicron- No issue.

35mm Summilux- No issue.

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Noah, I know you requested we not get off-track in discussing the "why" of the red edge - and just stick to a list of lenses that cause it.

 

Unfortunately, it does not seem to be linked only to specific lens optical designs, but also to either individual lenses or individual cameras (e.g. apparently Pascal gets red edges with a 35 f/2 ASPH and I don't. And I did not see red edges using my 21 on an M9 Sept. 9-10 - but I do get them with the identical lens on my early-production M9 received Sept. 17).

 

Which tends to indicate that it is not simply faulty corrections written into the firmware (which could be revised), but may be some kind of physical centering problem in specific lenses, or sensor placement within some bodies.

 

So there may be no simple list of lenses that do cause it or don't cause it.

 

That being said, certainly a list like this will reveal just that kind of inconsistency, which is good in its own way.

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Does anyone have any 'generic' CPF files for cornerfix they are willing to share?

 

Specifically I need one for the CV 15mm Heliar lens.

 

I tried to make one today but my grey card was not big enough to fill the frame... Is it OK to use a white wall instead?

 

I know its probably preferable to have one tailored for the specific lens, but note that the red edge spread seems very similar from my lens to other images I have seen posted here.

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Adobe Camera Raw 5.6 (and I presume, Lightroom 5.6 (?)) now has a graduated-filter tool, and by using it in color mode with the color set to the appropriate complementary green-cyan tint, narrow graduated green-cyan fades can be applied to neutralize the red. On multiple edges, if needed.

 

And then saved as a preset that can be applied with one mouse click to any subsequent image.

 

 

Andy LR has had the graduated filter tool for several iterations and I find it's VERY useful. I use exactly the same technique as you to fix red-shift with a Zeiss 18. The great thing is that it works really well as a pre-set that is simplicity itself to re-apply to a batch.

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Are there any 'how to' instructions on applying the graduated filter for this purpose. I am wondering a) how you apply it to specific parts of the photo if is localized and

what setting you use (exactly which colours).

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Which tends to indicate that it is not simply faulty corrections written into the firmware (which could be revised), but may be some kind of physical centering problem in specific lenses, or sensor placement within some bodies.

 

So there may be no simple list of lenses that do cause it or don't cause it.

 

That being said, certainly a list like this will reveal just that kind of inconsistency, which is good in its own way.

Hi Andy

 

I don't think it's remotely simple - and I'm pretty sure there won't be a silver bullet. There was a similar issue with the Kodak SLR/n. It was certainly lens dependent (I mean individual lenses). I'm sure it's also the case here - I think that all lenses are decentred to some extent or another, and this issue relates directly to the angle of incidence of the light at the edge of the sensor - only a tiny degree of off centre is going to make a difference here.

 

However, I do think that it's possible that in a rather over-enthusiastic attempt to remove all vignetting the settings in the first firmware make the matter worse than it needs to be.

 

So, in my opinion (for what it's worth), I'd guess that there will be a big improvement in future firmware (with a slight increase in vignetting), and that on the very rare occasions when it is still an issue it will be pretty simple to fix. Sandy's great work with cornerfix shows what can be done - even with 'difficult' lenses like the 15CV.

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Hi Andy

 

I don't think it's remotely simple - and I'm pretty sure there won't be a silver bullet. There was a similar issue with the Kodak SLR/n..

 

In the days of the Kodak 14N, did an explanation for the Italian flag effect ever surface? Do you think Leica might decide to release an "authorized version" of the problem and their eventual solution through a safe source like LFI?

 

scott

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The whole issue of "red edges" depends very much on white balance. If you use more than +3 tint in C1 you can easily produce the phenomenon with a 35-lux asph on a M8:

 

 

- as well as you can cure it by a very slight correction.

Edited by UliWer

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Is it OK to use a white wall instead?

 

I know its probably preferable to have one tailored for the specific lens, but note that the red edge spread seems very similar from my lens to other images I have seen posted here.

 

Yes, a white wall will be fine, if its evenly lit.

 

As mentioned by others, there are substantial differences between individual lenses and individual cameras, so the recommendation is that you create a profile specifically for your combination

 

Sandy

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In the days of the Kodak 14N, did an explanation for the Italian flag effect ever surface? Do you think Leica might decide to release an "authorized version" of the problem and their eventual solution through a safe source like LFI?

 

scott

 

Hi Scott

No - as far as I'm aware nobody got to the bottom of it.

As far as I'm aware nobody understands this effect either.

(of course, it's just conceivable that they just won't tell me

)

 

I think the best bet is yours (I think it was yours) that the combination of the extreme angle of the light and the lopsided rgb layout of the light sensors has something to do with it, and that it's exacerbated (or improved) by a slightly offset lens.

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The whole issue of "red edges" depends very much on white balance. If you use more than +3 tint in C1 you can easily produce the phenomenon with a 35-lux asph on a M8:

 

[ATTACH]185908[/ATTACH]

 

- as well as you can cure it by a very slight correction.

 

HI There

Is this the same thing? I think that this is just vignetting with a colour cast isn't it?

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Does anyone have any 'generic' CPF files for cornerfix they are willing to share?

 

Specifically I need one for the CV 15mm Heliar lens.

 

I tried to make one today but my grey card was not big enough to fill the frame... Is it OK to use a white wall instead?

 

I know its probably preferable to have one tailored for the specific lens, but note that the red edge spread seems very similar from my lens to other images I have seen posted here.

 

A very evenly illuminated smooth white or light gray wall may work. I live in the NW US, and used the sky (which is nearly always overcast and gray from November-April), and it works as well when I created a correction file for my 15mm Heliar.

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