16-9.net

The following data was compiled from independent MTF tests of Zeiss Contax lenses previously published here. Centre and border measurements were taken at every aperture (here represented in our conventional Zone A and B format, as it remains unknown whether the 'border' sample point lay in Zone B or C). Marks out of ten were awarded. The highest possible grade appears to be 9.0, but in fact one lens appears to have performed so outstandingly at one aperture that it gained a mark of 9.1. Amps to 11, then. You may or may not be surprised to learn that it was the cheapest lens they tested.

It has long been our contention, based on real-world experience, that the Zeiss 21mm would have achieved a grade in excess of 4.4 had it been tested by photodo – unprecedented for a sub-35mm lens. These MTF figures appear to support that position.

Lenses compared in the 18-28mm focal length range:

• Carl Zeiss 18mm f4 Distagon
• Carl Zeiss 21mm f2.8 Distagon
• Carl Zeiss 25mm f2.8 Distagon
• Carl Zeiss 28mm f2.8 Distagon

* Zeiss 28-85mm tested at f3.3

Fully validating the reputations of Distagon 21mm and the 25mm, these MTF measurements demonstrate just how good the 21mm is: recording ultimate figures centre frame (Zone A) at all apertures up to f5.6, and high scores throughout. The 25mm, by contrast, is dissected and found wanting: excellent performance centre frame from f5.6 up, but frankly poor Zone B performance at every aperture. Similar full frame performance was shown by earlier 16:9 tests of the updated ZF design.

The Contax 28mm f2.8 also confirms its status as the 'working aperture' wide angle of choice with impeccable performance from f5.6 and up. It isn't a wide aperture wonder (like the Leica 28mm), but stopped down a bit it outperforms even the legendary 21mm. What the distortion figures don't reveal is the complex waveform distortion pattern of the Zeiss 21mm which can only be corrected by a specialist application such as PTLens. Unfortunately, the 'Hollywood' 28mm f2 lens was not tested.

Last, and least, the data on the 18mm is as damning as the real world tests: it's a fine looking lens, until you look outside the A Zone. Ideal for APS-C sensors, then. It does sit well within the pattern, though: high resolution = high distortion; lower the resolving the power of the lens, and it can be well corrected in other areas.

Lenses compared at 35mm:

• Carl Zeiss 28-85mm f3.3-4 Vario Sonnar at 34mm
• Carl Zeiss 35-70mm f3.4 Vario Sonnar at 35mm
• Carl Zeiss 35-135mm f3.3-4.5 Vario Sonnar at 35mm
• Carl Zeiss 35mm f2.8 Distagon
• Carl Zeiss 35mm f2.8 PC (Perspective Correction)

Zeiss claimed that the 35-70mm f3.4 outperformed primes in its range: in many ways this wasn't hype. If you can overlook the strong barrel distortion, at 35mm this lens is literally as good as it gets, barring weak border performance wide open. These figures place the 9.0 rating of the Zeiss 21mm in sobering perspective.

Truly, though, all the Zeiss 35mm lenses are very fine indeed: the 35-70 may manifest the most consistent across-the-frame behaviour (the 28-85mm is the least impressive in this regard), but even the inexpensive 35mm f2.8 prime is well worth adapting to a Canon DSLR. The fast f1.4 prime yields superb images at wide apertures and the uncommon 35-135mm too bears favourable comparison with the class leaders centre frame, though the 35-70mm remains the only zoom lens fully competitive at this focal length with regard to Zone B and C performance.

Lenses compared at 50mm:

• Carl Zeiss 28-85mm f3.3-4 Vario Sonnar at 52mm
• Carl Zeiss 35-70mm f3.4 Vario Sonnar at 50mm
• Carl Zeiss 35-135mm f3.3-4.5 Vario Sonnar at 48mm
• Carl Zeiss 50mm f1.4 Planar
• Carl Zeiss 50mm f1.7 Planar
• Carl Zeiss 60mm f2.8 Makro Planar 1:1

* Zeiss 28-85mm tested at f3.3 and f4.

* Zeiss 35-70mm tested at f3.4

* Zeiss 35-135mm tested at f3.5

* Zeiss 50mm f1.7 tested at f1.7

Note here how the green markers have migrated away from the 35-70mm and towards the primes, which squabble among themselves for the lion's share of the plaudits at 50mm. The cheapest of them all – the Zeiss 50mm f1.7 – breaks the Zeiss 21mm ceiling by recording a stellar figure of 9.1 at f4 in Zone A. Actually, though, there's little difference between the best at most apertures: the slower 50mm prime is a hair less sharp than the f1.4 at f2 centre frame, but notably sharper in the corners; at f2.8, the f1.7 Planar is better overall. However, the f1.4 performs so strongly across the board that, combined with its extra speed and more attractive bokeh – and despite its relatively severe barrel distortion – it retains its premier status.

The surprise, perhaps, is a slightly weak showing from the 60mm f2.8 Makro, which enjoys urban legend status as the sharpest lens ever. In fact, its Zone B/C performance lags behind its more mundane siblings . . . at this subject distance. In reality, at close range, the 50mm primes struggle to deliver the sharp corners they draw at distance. Though the 35-70mm wins few green marks at 50mm, its performance remains excellent: actually peaking wide open centre frame here. The only lens that can't be recommend quite as strongly at this focal length is the 35-135mm.

Lenses compared at 70-100mm:

• Carl Zeiss 28-85mm f3.3-4 Vario Sonnar at 81mm
• Carl Zeiss 35-70mm f3.4 Vario Sonnar at 70mm
• Carl Zeiss 35-135mm f3.3-4.5 Vario Sonnar at 89mm
• Carl Zeiss 85mm f1.2 Planar
• Carl Zeiss 85mm f1.4 Planar
• Carl Zeiss 100mm f2 Planar
• Carl Zeiss 100mm f2.8 Makro Planar
• Carl Zeiss 80-200mm f4 Vario Sonnar at 81mm

This chart gives us a rare glimpse of the performance of the highly desirable 85mm f1.2 50 Jahre edition. It's also an exercise par excellence in nit-picking: in reality, all the primes are very close indeed. However, it does seem that the f1.2 lens enjoys a clear advantage in the outer image circle at wide apertures when compared to its slightly slower sibling, which doesn't hit the 8.0 mark in Zone B/C until f4. It's enlightening to compare Zeiss' short/fast portrait lenses with the often-overlooked (but easier to design) 100mm f2: at f2, its corner-to-corner performance is remarkable and at most apertures it represents the acme of excellence at this focal length. I guess that's what the extra $5K buys you: the same performance as the 100mm f2, with an extra stop and a half on top.

Again, we find the 100mm Makro Planar poorly represented: no doubt if the same tests were conducted at short range, we would see a clear reversal of the pecking order that seems to place the fast primes above the truly superb macro. Elsewhere, all the zooms look pretty good: the 35-135mm now finds itself level-pegging with lenses it trails at shorter focal lengths, and the uncommon 80-200mm f4 shows promise at the low end of its zoom range. However, as you might expect, none really pass muster when compared to these benchmark primes.