Zeiss Loxia 35mm f/2 Biogon: its Point Spread Function, and Why a Classic Balanced Optical Performance Might be Just Right
I returned to an old classic (meaning 3-4 years now!) on my recent outing with my daughter to Rock Creek in the Eastern Sierra.
This Sparkling Sun on Lake series evaluates sharpness, field curvature, longitudinal chromatic aberration, sunstar behavior and subsuming much of that, the point spread function. It is an excellent demonstration of the totality of a number of optical aberrations, but what dominates is what is often loosely termed sagittal coma flare, which is a misnomer, for it is not really flare caused by internal reflections, but a deviation of the point spread function from a point to a shape like bird’s wings.
In the above series, the point spread function was demonstrated including how it results in moderate contrast and micro contrast. That moderate contrast combined with the ultra-low distortion of the Zeiss Loxia 35mm f/2 Biogon combine to offer a pleasing visual effect that has a natural feel that may be well suited to photographic intents where the “feel” of an image is more important than absolute performance.
It is a pleasure to use the Loxia lenses while hiking; the Sony A7R III with a Zeiss Loxia lens is about the same weigh as a Micro Four Thirds camera, or less and is the closest one can get to the compact of a Leica M camera, but with more resolution and versatility.