Canon EF 85mm f/1.2 USM L II - Full Format Review / Test - Analysis
Lens Reviews - Canon EOS (Full Format)

Distortion

The 85mm L II shows a moderate degree of barrel distortion (1%) when used on a full format camera. This can be visible at times but it's not really a significant problem.

Vignetting

The amount of vignetting is quite hefty (~1.8EV) at max. aperture but this is not out of the ordinary for such an ultra large aperture lens either. The problem is already very much reduced at f/1.6 and not really field relevant anymore from f/2 onwards.

MTF (resolution & chromatic aberrations)

The lens produced superb resolution figures in our corresponding APS-C test but it's fairly obvious that the full format image field is a more difficult playground - for the border quality at least. The center is already very good at f/1.2 - a bafflingly high performance at this setting - whereas the border and corner quality is "only" moderate. The center reaches excellent results at f/1.6 and keeps this level till f/8. The border quality improves slowly towards smaller apertures - it's "good" (just) at f/1.6 and "very good" from f/4 onwards. The peak performance is reached around f/5.6 with an outstanding center and a very high border/corner quality. Diffraction effects start to have a higher impact from f/11 onwards.

Below is a simplified summary of the formal findings. The chart shows line widths per picture height (LW/PH) which can be taken as a measure for sharpness. If you want to know more about the MTF50 figures you may check out the corresponding Imatest Explanations

Lateral Chromatic Aberrations (CAs)

Lateral chromatic aberrations (color shadows at harsh contrast transitions) are extremely well controlled and not field relevant. Surprisingly the aspect does not worsen compared to the APS-C scope test.

Bokeh

The bokeh (the quality of the out-of-focus blur) is a primary aspect for an ultra large aperture lens and the 85mm L II does not disappoint us here. The blur potential is more than extreme! If required this lens will smoothen even the most difficult back- and foregrounds. The technical quality of the bokeh is also excellent. Out-of-focus highlights are rendered perfectly and the blur is very smooth.

The following 100% crop illustrates both the blur capabilities of the lens as well as the very high contrast and center resolution at f/1.2:

Bokeh Fringing / Longitudinal Chromatic Aberrations (LoCA)

Bokeh fringing at large aperture is a problem which is often not well corrected even by the very best lenses and the EF 85mm f/1.2 L II is no exception to the rule. If you have a look at the provided sample crops below you should be able to spot a purple halo in front of the focus zone and a green one beyond. The effect is clearly visible from f/1.2 till f/2.8.

Move the mouse cursor over the f-stop marks below to observe the respective LoCAs
f/1.2 f/1.6 f/2 f/2.8




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