Leica APO-Summicron-SL 75 mm f/2 ASPH. review - Vignetting

Have you rated your lenses yet?

Leica APO-Summicron-SL 75 mm f/2 ASPH.

18 August 2025

Maciej Latałło

8. Vignetting

In case of full frame systems we usually provide results both for the smaller APS-C sensor and full frame. It is connected to the fact that Canon, Nikon, Pentax, Sony, or Sigma systems feature one mount that allows to join full frame lenses to both full frame and APS-C/DX bodies. Information about vignetting or distortion levels for the second, smaller detector is very important for one part of users. Panasonic also has been developing two systems, the L-mount and the Micro 4/3; still they are not compatible with each other so lenses designed for one systems cannot be attached to the other system cameras. In case of Leica the situation is different. SL lenses can be attached both to full frame bodies and to a bit older APS-C models such as the Leica T, TL, TL2, or CL. Still, we would like to approach all L-mount devices in the same way so we are going to examine vignetting (and also distortion) only for a full frame detector.

As you could notice in previous chapters the data obtained on the edge of the APS-C/DX sensor are left for resolution and chromatic aberration measurements. In these cases it was important because it provides additional piece of information about the layout of sharpness and chromatic aberration across the whole analysed frame.

First let's deal with vignetting observed for uncorrected JPEG files.

Please Support Us

If you enjoy our reviews and articles, and you want us to continue our work please, support our website by donating through PayPal. The funds are going to be used for paying our editorial team, renting servers, and equipping our testing studio; only that way we will be able to continue providing you interesting content for free.

- - - - - - - - - - - - - - - - - advertisement - - - - - - - - - - - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

S1R II, FF, JPEG, f/2.0	S1R II, FF, JPEG, f/2.8

S1R II, FF, JPEG, f/4.0	S1R II, FF, JPEG, f/5.6

Huge dimensions of Leica allow it to produce a quite sensible performance in this category. At the maximum relative aperture the brightness loss in the very corner of the frame amounts to 40% (-1.46 EV). This result still fits a range of moderate values although I admit it is very close to its borderline. The fact that vignetting drops very quickly on stopping down also should be praised. By f/2.8 you deal with a small value of 22% (-0.72 EV) and by f/4.0 and f/5.6 this aberration becomes practically completely imperceptible, with results of 10% (-0.30 EV) and 4% (-0.13 EV) respectively.

As a kind of a bonus we would like to present vignetting results for uncorrected RAW files that provide you a tad wider field of view than JPEGs.

S1R II, FF, RAW, f/2.0	S1R II, FF, RAW, f/2.8

S1R II, FF, RAW, f/4.0	S1R II, FF, RAW, f/5.6

In this case at the maximum relative aperture the brightness loss in frame corners reaches 45% (-1.74 EV) and it decreases to 27% (-0.92 EV) on stopping down the aperture to f/2.8. Applying f/4.0 aperture makes this aberration decrease to a very slight value of 13% (-0.42 EV), and all problems end by f/5.6, where we got a result of just 6% (-0.18 EV).

Panasonic S1R II, JPEG, 75 mm, f/2.0