Normal Retro

At sites like dpreview and photo.net there's been plenty of gnashing of teeth over the past few months about the upcoming Sigma 30mm f/1.4 prime lens for DSLRs. Price speculation, weight speculation, and quality speculation. As much as I like my Zeiss Distagon 28mm, it's often hard to focus using the 300D's tiny "prison window" finder. Rather than dropping $3K on a 1D, I've been cosnidering having a fast AF alternative. I thought I'd sum-up what's known for Canon users by comparing it to some of the existing Canon offerings:

* at Adorama

All lenses are USM (HSM) with FTM, except the 35f/2 and the 50f/1.8 (the Zeiss is Manual Focus). The APS-C field is too small for the 1D MkII's "APS-H" sensor.

Sigma also makes a 28mm f/1.8 for EOS, but it's huge (filter size 77mm), heavy (almost 600 grams), and without HSM I'm not really all that interested in it.

Why are these small lenses so... giant? Basically, because even for a small-sensor camera in EOS mount (or Nikon, or Pentax...), the DSLR flange-to-sensor distance is above 40mm — that means that a lens with 28mm or 30mm focal length needs to use a retro-focus design to hit the film/sensor waaaay in the back of the body. This is one aspect that 4/3-system cameras like the Olympus could — but so far haven't — exploited as an advantage.

The lack of f/22 seems like a real loss for the Sigma — sure it's a half-stop faster, but does it have any other possible advantage over the Canon 1.8?

(PS: As of 6 June the price offered at Amazon on the Sigma, still pre-release, is down to $389.94)