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This aperture series at f/2, f/2.8, f/4, f/5.6 shows off the world class performance wide open at f/2 of the Leica 90mm f/2 APO-Summicron-SL ASPH on the Panasonic S1R shot in 187-megapixel Multi-Shot High-Res mode.
It also shows a focus shift such that f/2.8, f/4, f/5.6 are all substantially degraded from f/2, even down to sizes as small as 24 megapixels.
Images at up to 187 megapixels for f/2 and f/4 plus crops at f/2, f/2.8, f/4, f/5.6 in various places from the 187 megapixel resolution.
I loathe doing field work with a lens having focus shift when I have no means of compensating for, that is wasting my effort by never knowing until day’s end back at the computer whether I have made a fully sharp image, and only by always shooting also at f/2, for a baseline gauge of sharpness. I am not aware of any reliable method on the Panasonic S1R to ensure optimal focus for a specific aperture, something that would compensate for the focus shift.