Pete Myers;529 wrote: … I took a look at some full size images from this lens over here:
http://www.lenstip.com/1835-news-Leica_Summarit-S_35_mm_f_2.5_ASPH._-_sample_images.htmlI found it astonishing how much chromatic aberration was present in the images presented. I am not sure how to account for it …
Well—I don’t have an S2, much less any Summarit-S lenses … but I do own several good lenses including some Leica M lenses, and I’d consider the amount of chromatic aberration seen in the test images from the link given above as normal, even for an expensive high-end lens. Even the best lenses still aren’t perfect, and when pixel-peeping then you will always find a minor fault or two.
I downloaded one of the test images from lenstip.com and tried to remove the colour fringes in Camera Raw. I arrived at red/cyan -9 and blue/yellow +4. That’s pretty low figures, almost worthy of an apo lens. One of my shots taken with the Summilux-M 35 mm Asph at medium distance can use R/C -3, B/Y +9; a Summilux-M 50 mm Asph (which allegedly has apo correction) image gets near-perfect with R/C -8, B/Y +2 (YMMV). So with regard to the magnitude of the chromatic aberration, they all are in the same ballpark. I’d say for a non-apo wide-angle lens, that’s very good performance and nothing to worry about.
Furthermore, for Adobe Camera Raw and Photoshop Lightroom there’s a very elaborated lens profile for the Leica Summarit-S 35 mm Asph which includes corrections for all combinations of apertures and distances. However you need to shoot in raw format in order to take advantage of it. I wish such profiles were available for the Leica M lenses, too …