Carl Zeiss on lens distortion

Just posted is a new white paper on distortion by B. Hönlinger and H. H. Nasse. You can also read a brief summary of distortion.

One of the lowest distortion lenses available is the Zeiss ZF 100mm f/2 Makro-Planar. The Zeiss ZF/ZE 85mm f/1.4 Planar is also very low distortion. For details on both, see Guide to Zeiss ZF/ZE Lenses.

When we talk about distortion with wide angles lenses, it’s all relative; “low distortion” can mean “quote noticeable warping” with some subjects. Very few wide angle lenses are free from distortion; the most common is barrel distortion (outward bowing), but “wave” or “moustache” distortion is becoming much more common with advanced designs. Remember, optical design is all about compromises, and it’s hard to banish distortion without resulting in some other reduction in performance; lens designers would eliminate distortion if it were easy!

Shown below is the distortion graph for the Zeiss ZF/ZE 21mm f/2.8 Distagon. On a smaller sensor (Nikon DX or Canon EF-S), distortion will appear as barrel distortion. On full frame, distortion will be visible as wave-type distortion. Compare the distortion graph to that of the Zeiss ZF/ZE 85/1.4 Planar and ZF 100/2 Makro-Planar, then see the examples that follow.

Distortion graph for Zeiss ZF/ZE 21mm f/2.8 Distagon: wave type distortion

Distortion graph for Zeiss ZF 100mm f/2 Makro-Planar: ultra-low distortion

Distortion graph for Zeiss ZF/ZE 85mm f/1.4 Planar: ultra-low distortion

The examples below show the wave-type distortion which can be of concern for architectural photography, whether at distance or closer range.

Architectural photography raises concerns about distortion
Note the visible reversal (“wave”) from barrel to pincushion in the horizontal black line

Man-made objects are the most problematic due to their regularity
Ignore the bent area about 1/3 down, but the rest is lens distortion