Chromatic Aberration, How Important in One's Evaluation of a Lens?

Msmoto

As I will sometimes do a bit of pixel peeping in editing my images, I am often confronted by the chromatic aberration at the magnification level I use.
And, it came to mind that maybe the CA is far more important in the ranking of lens performance than I had realized. Note, I did not say sharpness but performance as the combined result is where my interest lies. Looking at three fine lenses on DxOMark, I find some interesting numbers, and in fact these results suggest to me why I love my Sigma 35mm f/1.4, and why its rating on DxOMark is very high. But, the CA only today, as measured by DxOMark on a D800.

Nikon AF-S NIKKOR 35mm f/1.4G CA 15µm

Sigma 35mm F1.4 DG HSM A Nikon CA 6µm

Carl Zeiss Distagon T 35mm f/1.4 ZF2 Nikon CA 9µm

Maybe some others can pop in and give their thoughts regarding where CA falls in their priorities of lens evaluation. For me, I think it is near the top.

PB_PM

CA drives me nuts, so if a lens exhibits a lot of it I steer clear. I know you can deal with it in post, at least to some degree, but I'd rather not have to deal with it in the first place.

ThomasHorton

at what micron level does CA become visible when not pixel peaking?

Msmoto

Well, the effect of CA, IMO, is highly subjective. For example:
Carl Zeiss Apo Sonnar T* 2/135 ZF.2 Nikon has only 2 µm,
Nikon AF-S VR Micro-Nikkor 105mm f/2.8G IF-ED, a very respected lens has 7 µm.
Sigma 35mm F1.4 DG HSM A Nikon has 6 µm
Nikon AF-S NIKKOR 35mm f/1.4G which is not as good with 15 µm.
All data are from DxOMark on D800..

sevencrossing

Yes CA used to be problem when doing graphs for an AV presentation
and serious architectural stuff
but today, I mainly do landscapes and portraiture; I don't think I have ever noticed it

haroldp

Since at any given level of size, cost, light circle etc., competent designers trade of various corrections (fallof, resolution, contrast acutance, distortion, ca and other aberations, center vs edge etc.) It appears to me that many modern lens designers are letting go aberrations that are easily corrected digitally (distortion, lca) to optimize those that are not so easily corrected. As long as the correction is good, and easliy assimilated into the workflow, this seems reasonable to me.

The 18-200 was almost unusable to me because of severe (and complex) distortion, and CA.
When NX2 allowed auto correction of these, I revisited old NEF's and extracted several images that I liked. Unfortunately, by that time I had moved to FX and never used the lens again.


... H

jagiv

Sharpness is at the top of my list. CA, barrel distortion and vignetting can all be gone with the click of a button in Lightroom.

spraynpray

CA is very important to me. I recently became infatuated by Canon lenses because of the better range they offered for their crop sensor cameras but when I looked closer, generally their CA was terrible. My most used lens is the Nikkor 17-55 f2.8 and the CA is pretty good on that one but my friends Canon 17-85 is dreadful. I saw an image from their 24-105 the other day, and that was even worse. Both of those lenses were used on Landscape shots and both of them showed badly in tree branches. Both are so bad you cannot get rid of it entirely in post. When I do give my 17-55 a difficult enough subject to make CA visible, a simple click removes it which is fine. He has just bought the 18-35 f1.8 Sigma and although that is a brilliant performer, I can't see me swapping my 17-55 for one.

TaoTeJared

CAs have a large part in sharpness that many forget. Chromatic Aberration is the separation of light into colors and that equates to edges becoming "fuzzy". It also has a large impact on Bokeh as well (usually in a good way.)
To me anything above 10µm is not good for any "technical" work but can be great for portraiture.

heartyfisher

I really dislike CA.. annoys the heck out of me.. but the auto corrects have help a lot however some images cant be corrected in software.. loved my 18-200 but some/many images were uncorrectable due to the high level of CA. but the newer lenses from Nikon seems to have much lower CA. eg the 18-135 was infamous for CA but the new 18-140 is very well behaved! yes CA is a high priority for me when evaluating lenses.

tcole1983

I never notice it in my Nikon lenses, but I did notice it on my Tokina 12-24 which ultimately led to me getting rid of it. My Tokina also exhibited some wicked ghosting and lens flare which I also didn't like. Shot at the same time as my Nikon lenses and my Nikons never have had the problems to a noticeable degree.

I do always click my Lightroom button to correct for my lenses so it isn't really a bother. And I believe if I shoot jpeg they come out of the camera corrected anyway.

tcole1983

Double post, but I will use this to post an example:
Ghosting: