The Zeiss 135mm f/2 APO-Sonnar (reviewed in Guide to Zeiss) might fairly be called the best lens for a DSLR on the market today. It offers performance at the level of the best Leica R APO glass (or Leica M APO) yet offers the native mount capabilities for Nikon and Canon DSLRs. And on a 36-megapixel Nikon D800E, it suggests that a 56-megapixel Nikon D4x would not be too demanding, not at all.
Wide open at ƒ/2 the Zeiss 135/2 APO-Sonnar outperforms many lenses at any aperture, and by ƒ/2.8 it can be fairly be said to outperform all but a handful of DSLR lenses on the market today. Actually, I would not be comfortable stating that I know of a lens that can outperform it, though this is possible.
In the field, the Zeiss 135mm f/2 APO Sonnar is superlative. It is a must-have optic representing the very best optical performance of the Zeiss ZF.2 / ZE lens line.
The Zeiss 135/2 APO-Sonnar is about $2129 at B&H Photo.
Perspective is useful; shown below is the MTF chart for the Zeiss 135/2 APO-Sonnar and the vaunted Leica M 90mm f/2 APO-Summicron-M ASPH.
Unlike MTF charts from most vendors, the Leica and Zeiss charts can generally be compared fairly (not so for Nikon, Canon, Sigma, Sony.fantasy).
Note well: the Zeiss results here are MEASURED from an actual production lens (mine). The Leica results are from Leica’s official data sheet, and it’s unclear if they are “real” (from an actual production lens as opposed to computed).
So what does MTF tell us here?
At ƒ/2, the Zeiss 135/2 easily outperforms the Leica 90/2 APO for fine structures (40 lp/mm), showing MTF across the field that is 10% or so higher. My field shots with both lenses leave me no doubt that the Zeiss is a superior lens at ƒ/2.
At ƒ/5.6 the Zeiss 135/2 APO shows higher overall and peak contrast for fine structures and overall, but some astigmatism to the edges and corners. Both lenses are at a very high level, call it a draw with the Zeiss stronger centrally and the Leica 90/2 APO a bit stronger in the corners if one discounts the Zeiss 135/2 for astigmatism. Still, I’d place my bet overall on the Zeiss 135/2 APO, based on what I see in field images.
Which brings us to another practical issue: a 36-megapixel Nikon D800E blows away anything from Leica in terms of achievable detail and image quality, and at a far lower price. Yet another consideration: the Leica 135mm f/3.4 APO is 1.5 stops slower than the Zeiss 135/2, costs $1200 more and performs at a notably lower level.
MTF for Leica 90mm f/2 APO-Summicron-M ASPH below. At ƒ/2 it underperforms the Zeiss 135/2 APO-Sonnar at ƒ/2. Stopped down to any aperture, it cannot match the peak central contrast of the Zeiss at ƒ/2.
The Leica 135mm f/3.4 APO-Telyt-M ASPH is 2/3 stop slower and cannot perform to the level of the Zeiss 135mm f/2 APO-Sonnar at any f-stop.