bbalushev
The Sigma 8mm has been one of the workhorse lenses for virtual imaging with dSLR cameras.
When considering the 8mm by reading comments on various forums, make sure you know whether they are talking about the old f/4 or the newer f/3.5.
If you are producing print panoramas like the few I've created, the 17-40mm is probably the lens to use. I'm assuming you're only printing a view that's 180° wide or less.
According to Canon's lens chart the 17-40mm is from 104° to 57° from corner to corner. Shooting in portrait postion, you'd have plenty of vertial Field of View and need about 5-6 shots horizontally to get about 1/3 overlap for stitching.
The Sigma 8mm could take 180° wide shot in just one shot, but you won't have as much resolution/detail as you'd get with multiple shots.
Simply, you will shoot a lot fewer shots with the Sigma 8mm. From the results I've seen, its a great lens for full 360° spherical images to be displayed on a computer screen. But if resolution/detail for printed panoramas is what you want, more shots will deliver them. And there wouldn't be a lot of difference in the number of shots between your 17-40mm and the Sigma 12-24mm
Personally, I'd keep using the Canon lens for print panoramas and buy the Sigma 8mm for 360° interactive spherical images
Message edited by djaurand on 12-02-2007 at 05:46:13 PM
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Douglas Aurand
Albuquerque, NM
Showing Albuquerque to the World on www.VirtualAlbuquerque.com
