Canon Full Frame Test: Zeiss ZF 25mm Distagon
Zeiss ZF 25mm f2.8 v Canon 24mm f1.4 L
Arriving a little late for the big 24mm tournament last year, the Zeiss ZF 25mm was nonetheless chosen to participate in a special play off against the winner of that review: the Canon 24mm f1.4 L. The Distagon is an all-new design conforming to Carl Zeiss' new 'long formula' for wide angle lenses pioneered so successful with the 21mm f2.8. It measures 65mm in length and focuses down to an astounding 6cm from the front element: practically qualifying for a 'macro' designation. Mindful of the importance of the right adaptor, prior to testing proper, the ZF was tested with the Fotodiox Pro version so succesfully used on the Nikon 17-35mm and 15mm AIS, as well as a thinner, Chinese-made item that seems to be quite at home on the Nikon 28mm f2.8 AIS. No differences were found (see conclusion for details). In the flesh, the Zeiss exudes high quality construction: out of the box, the focus is tight, but it does loosen with use.
The MTF charts look promising enough, though there appears to be a steeper than expected drop off in corner resolution. We'll see if that is borne out in practice – and whether a full frame Canon sensor can tell the difference . . .
The Canon 24mm f1.4 L is a well proven design, but the lens perhaps doesn't have the reputation it deserves. Certainly its specification is unique (there is no lens faster at this focal length) but a number of older reviews have indicated severely compromised corner performance. In my experience, this is not true. The lens has UD and aspherical elements and a floating element for close range work. We'll see shortly how important this is. Its minimum focus is a none-too-shabby 9.6 inches and it weighs 558g against the ZF's 480g. It's a fraction longer, and obviously the front element is much larger: a 77mm thread on the front rather than the Distagon's 58mm. Here are Canon Japan's MTF figures, presumably wide open, but it's anyone's guess:
So much for the theory. How rosy are they in the garden?