But two things annoyed me about it. The first was that it didn't quite reach that magic angle of view of a bit more than 90 degrees. That's the angle which is wide enough from edge to edge to just get all four walls of a room in the shot if the camera is tight up in the corner. The second was that a lot of my shots with the 10-20mm were at 10mm, confirming my subjective impression that quite often I'd crank it wide and hit the stop, wishing it was just a bit wider.
The reviews so far of Sigma's 8-16mm (from photozone.de and lenstip) look good.
http://www.photozone.de/canon-eos/515-sigma816f4556apsc
http://www.lenstip.com/index.php?test=o ... est_ob=246
I'm still finding out what it can do and how to use it, but so far I'm impressed. It's comfortably past the magic 90 degree boundary at 112 degrees. At f8 it seems about as sharp as the 10-20mm, but unlike that lens, maintains the sharpness well when the aperture is opened up. It may even be a bit sharper at f5.6.
I thought the internal focus motor would be an unnecessary luxury, but it permits the lens AF to to be switched on and off much more easily than the rather awkward AF/MF switch on the A350/550 (and possibly other Alphas). It also has a very nice clutch on the manual focus ring, which lets you trim focus manually with AF engaged just by moving the ring. I find AF a bit iffy on these ultra wide lenses, and get better results by using manual focus. The easy switch and focus ring clutch on the Sigma 8-16mm make slipping between AF and manual focus delightfully easy.
Like Sigma's 10-20mm, the 8-16mm has a little curl of barrel distortion at the edges of its widest angle. I like that, because in wide angle group shots it reduces the width of the people at the edges of the image, which they usually prefer
For precisely rectilinear architectural shots it corrects easily in such lens correction utilities as PTLens which use a database of specific lens geometry distortions. In fact I was impressed to discover that PTLens already recognised this lens and corrected it perfectly.Here's an interior view of the quadrangle of Edinburgh University's Old College. I didn't have to step right back into the corner to get the four walls in, and there was enough extra to do a bit of tilt and perspective correction and the consequent slight cropping down.
and an URL from which larger sizes can be obtained via the "actions" button.
http://www.flickr.com/photos/chris_malcolm/4735081540/
Here's a wide long perspective street view.
and an URL from which larger sizes can be obtained.
http://www.flickr.com/photos/chris_malcolm/4741252207/
