The Zeiss ZM 21/4.5 C-Biogon is a worst-case lens for digital sensors: its 44.4° chief ray angle is the least friendly to a digital sensor of all the Zeiss ZM lenses; even on the Leica M bodies its color shading is problematic.
In Guide to Leica:
Includes HD images up to 4320 pixels across the f/2 - f/11 aperture range as well as HD crops from both the stock A7R and Kolarivision A7R.MOD can be easily compared. With commentary.
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