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Lens review

Panasonic Leica DG Vario-Summilux 10-25 mm f/1.7 ASPH

23 September 2019
Maciej Latałło

8. Vignetting

First let's check how vignetting looks in JPEG files – appropriate thumbnails, generated with the help of the Olympus O-MD E-M5 Mark II camera, you can find below.

E-M5 II, JPEG, 10 mm, f/1.7 E-M5 II, JPEG, 10 mm, f/2.0
Panasonic Leica DG Vario-Summilux 10-25 mm f/1.7 ASPH - Vignetting Panasonic Leica DG Vario-Summilux 10-25 mm f/1.7 ASPH - Vignetting
E-M5 II, JPEG, 17 mm, f/1.7 E-M5 II, JPEG, 17 mm, f/2.0
Panasonic Leica DG Vario-Summilux 10-25 mm f/1.7 ASPH - Vignetting Panasonic Leica DG Vario-Summilux 10-25 mm f/1.7 ASPH - Vignetting
E-M5 II, JPEG, 25 mm, f/1.7 E-M5 II, JPEG, 25 mm, f/2.0
Panasonic Leica DG Vario-Summilux 10-25 mm f/1.7 ASPH - Vignetting Panasonic Leica DG Vario-Summilux 10-25 mm f/1.7 ASPH - Vignetting


For a very difficult combination of f/1.7 aperture and wide angle of view at 10 mm the brightness loss in frame corners amounts to 49% (−1.93 EV). It is a significant value but with these parameters it would be foolish to expect anything distinctly better.

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By f/2.0 vignetting decreases to 39% (−1.43 EV), and by f/2.8 to 21% (−0.60 EV). The problem becomes insignificant by f/4.0 and f/5.6 apertures where the described aberration reaches respectively: 13% (−0.40 EV) and 12% (−0.36 EV).

It's worth mentioning that for RAW files, where distortion is not corrected and the field of view- larger, the results we got at the 10 mm focal length are by 4-7% higher.

In the middle of the focal range vignetting problems become noticeably less serious, mirroring differences between JPEG and RAW files. By f/1.7 light fall-off in the frame corners amounts to 38% (−1.38 EV), by f/2.0 it decreases to 31% (−1.07 EV), and by f/2.8 to 24% (−0.80 EV). By f/4.0 and f/5.6 apertures you deal with a slight level of that aberration and we got, respectively, the following results: 18% (−0.56 EV) and 12% (−0.37 EV).

At 25 mm focal length vignetting increases slightly if you compare it to the situation at 17 mm. In the case of the maximum relative aperture you have to take into account brightness loss of 42% (−1.57 EV), and by f/2.0 you have to deal with the loss of 32% (−1.10 EV) of light. By f/2.8, f/4.0 and f/5.6 apertures we got the following numbers: 25% (−0.83 EV), 19% (−0.61 EV) and 13% (−0.42 EV) respectively.

Olympus O-MD E-M5 Mark II, JPEG, 10 mm, f/1.7
Panasonic Leica DG Vario-Summilux 10-25 mm f/1.7 ASPH - Vignetting
Olympus O-MD E-M5 Mark II, JPEG, 17 mm, f/1.7
Panasonic Leica DG Vario-Summilux 10-25 mm f/1.7 ASPH - Vignetting
Olympus O-MD E-M5 Mark II, JPEG, 25 mm, f/1.7
Panasonic Leica DG Vario-Summilux 10-25 mm f/1.7 ASPH - Vignetting