Originally posted by carpents I've criticized Pentax in the past for not taking advantage of the one benefit of APS-C (namely, the smaller physical size). I have clamored here before asking for a 50-135/2.0 or a smaller version of the 80-200/2.8...the 50-135/2.8 is neither of those things.
What, so the 50-135, at 76mmx136mm and 685g without hood it's not small enough? And a 67mm filter. The FA*80-200 is 88x195mm and weighs over twice as much at 1500g. That doesn't stand up at all. I have no issues shooting with the K10D and a 1.3kg Sigma 70-200, and that's without a monopod.
Also, given the way aperture is calculated (aperture diameter relative to focal length) it's not possible to do a smaller 80-200 f2.8.
Look at lenses like Nikon's AF-S 17-55 f2.8. It's huge, and designed specifically for APS-C. SLR photography is not really about convenience of pocketable cameras, it just compromises IQ and design.
Also, as for faster zooms such as f2.0 constants, the only company which has produced anything of the kind is Olympus/Zuiko for the 4-3rds system. Which is a 2x crop factor and further compounds the issues of APS-C compared to FF. Adorama lists the Zuiko 35-100 f2.0 at $1949 (admittedly with a $250 rebate). Would you be willing to pay that? And look at the size of it. 96.5mmx213.5mm and 1650g.
Similarly, the Zuiko 90-250 f2.8 at $5349. 124mmx276mm, 3270g.
Of course most of these figures are meaningless because it's in metric and not the ridiculous imperial figures. 25.4mm = 1" and 1000g roughly equals 0.5lb. Aren't I nice?
(no, I know I'm not)