How to remove color shift and keep vignetting?

[edwardkaraa]

Hi All,

I have been using so far the Leica lens correction in camera to remove the color shift on the ZM 18 and 25. I found the best equivalents in a list that I received from Zeiss upon request, but it is also available on the Leica user forum. Now while the profiles are successful in removing the color shift entirely on the 25 and and partially on the 18, they happen to remove vignetting in a very unnatural way, that makes the photos look somewhat flat. I prefer the natural vignetting in lenses as it adds to their character.

So any suggestions?

 

[Shashin]

You could try converting the image to lab color space and then opening curves and selecting the a curve and then flattening it out--if the curve intersects the center, the color balance should be preserved.

The only other way would be making a flat frame and removing the luminance information keeping only the color and then subtracting it from you image.

 

[edwardkaraa]

Thank you shashin. In other terms, it's not possible

 

[douglasf13]

Yeah, you can keep the vignetting if you use CornerFix, but I don't think you can with the Leica profiles, although I guess you could always add vignetting back in Lightroom.

FWIW, keep in mind that digital vignettes more than film, so getting rid of some of the vignetting gets things closer to how many of these lenses were intended to look on film, if that matters at all.

 

[edwardkaraa]

Thanks Douglas,

I tried to do profile shots for the 18 and 25 but found it next to impossible because of the very wide angle of view. Also I have found out that both lenses produce no color shift at close distances. I have the impression the shift starts at about 3 meter. So the correction is required at infinity only. I think should get myself an expo disc, that should help making the profile shots easier.

 

[Taylor Sherman]

I've had good luck making profile shots by holding the lens right up against a computer monitor showing a white page, +2EV. This was with a Nex though, not an M9.

 

[edwardkaraa]

That's sounds like a great idea Taylor. I will try it tonight. Thanks!

 

[250swb]

So any suggestions?

I guess this may be too simple, but why not let the profile remove the vignetting then manually re-do the vignetting? It is an easy enough job in post processing and has got to be a simpler action than going all around the houses trying to remove the colour cast without removing the vignetting.

Steve

 

[edwardkaraa]

Good idea, Steve. Thanks!

 

[edwardkaraa]

Here are a few experiments with Zeiss recommended profiles. Shot at f/8 at infinity focusing distance.

ZM 25:

Off - 24/2.8 asph - 28/2.8 asph

View attachment 64728

View attachment 64729

View attachment 64730

 

[edwardkaraa]

ZM 18:

Off - 24/2.8 asph - 28/2 asph

View attachment 64731

View attachment 64732

View attachment 64733

 

[Double Negative]

I use both with the M9 and found that they're generally best coded as an Elmarit-M 21mm f/2.8 ASPH. That depends on the framelines they bring up, however:

Leica Lens Codes

You can also try using Cornerfix - but that's a complete correction solution. You'll probably want to add back in your own vignetting.

 

[250swb]

They look OK Edward. The vignetting isn't as much as I imagined you wanted, but with almost any photograph even a small amount of burning of the edges helps hold the image 'in the frame' and compensates for the optical illusion of the image getting lighter towards the edges when set against a light coloured background.

Steve

 

[Taylor Sherman]

I use both with the M9 and found that they're generally best coded as an Elmarit-M 21mm f/2.8 ASPH. That depends on the framelines they bring up, however:

Leica Lens Codes

You can also try using Cornerfix - but that's a complete correction solution. You'll probably want to add back in your own vignetting.

Cornerfix lets you adjust the amount of color correction and falloff correction independently. Though, I can't say the results are always what you'd expect. I've made profiles that work OK with both corrections at 100%, but get ugly when I try to leave the falloff alone (just correct color). I have got one now that lets me use 0% for falloff and 100% for color, which is what I like.

 

[Hosermage]

When I owned the 25mm ZM, I also tried both 24mm vs 28mm profile. What I found was that using 28mm, it removed the color corners but had more vignette. When I used it as 24mm, it had no vignette but had a slight redness in corners, but only if I shoot the sky, so it was negligible in normal use.

I think I would have preferred to code it as 28mm Elmarit-M ASPH, but I ended up coding it as 24mm because I actually had a real 28mm, so I didn't want to confuse them in Lightroom.

 

[Double Negative]

Cornerfix lets you adjust the amount of color correction and falloff correction independently. Though, I can't say the results are always what you'd expect. I've made profiles that work OK with both corrections at 100%, but get ugly when I try to leave the falloff alone (just correct color). I have got one now that lets me use 0% for falloff and 100% for color, which is what I like.

Hmm, true. I have to admit, I used it rather briefly before the second to last round of M9 firmware came out and improved things quite a bit. That and sheer laziness on my part. I like the vignetting too. The "red edge" or "Italian flag" coloring can be a pain though. It can be corrected to varying degrees with a gradient applied during import or cropped out... Worse comes to worse, try a B&W conversion. Whee. Part of why I ended up moving to Leica glass.

 

[Double Negative]

A recent pic from the M9 and 4/18 coded as a WATE. Ideally and as I tested it, works best as an Elmarit-M 21mm f/2.8 ASPH. I forgot exactly why offhand - either it won't read another code because of a screw, or the framelines it brings up... Either way I'd need a modified flange. Solution there is to set it manually, which I forgot to do in this shot. You can see a bit of the red edge on the left (the rest I cropped).

 

[edwardkaraa]

Cornerfix lets you adjust the amount of color correction and falloff correction independently. Though, I can't say the results are always what you'd expect. I've made profiles that work OK with both corrections at 100%, but get ugly when I try to leave the falloff alone (just correct color). I have got one now that lets me use 0% for falloff and 100% for color, which is what I like.

Same experience here. I did create profiles and they just produce weird colors. Quite inconsistent, but I think it is due to my laziness not setting up a proper lighting.

 

[edwardkaraa]

When I owned the 25mm ZM, I also tried both 24mm vs 28mm profile. What I found was that using 28mm, it removed the color corners but had more vignette. When I used it as 24mm, it had no vignette but had a slight redness in corners, but only if I shoot the sky, so it was negligible in normal use.

I think I would have preferred to code it as 28mm Elmarit-M ASPH, but I ended up coding it as 24mm because I actually had a real 28mm, so I didn't want to confuse them in Lightroom.

Agreed, David. I prefer the 28 profiles because they do not remove vignetting completely but seem to be more efficient with the Italian flag.

 

[edwardkaraa]

I use both with the M9 and found that they're generally best coded as an Elmarit-M 21mm f/2.8 ASPH. That depends on the framelines they bring up, however:

Leica Lens Codes

You can also try using Cornerfix - but that's a complete correction solution. You'll probably want to add back in your own vignetting.

Thank you Michael. I will try the 21 profile asap. Nice shot of the 4wheeler by the way