davidkilpatrick's reviews

Tamron 17-35mm f/2.8-4 Di SP AF

The Tamron 17-35mm has been much maligned; test chart results never work with such lenses, as the targets are always too close when trying to measure distortion or field flatness at 17mm. In practice, with interiors, architecture and general scenes (distant subjects, relative to a 17mm focal length) the Tamron proves to have first-class orthographic geometry across its whole zoom range. This means your seascape won't have a curved horizon, your buildings will have parallel straight walls if you get the camera trued up to vertical, and you will not need software correction for many subjects.

I have been used the 17-35mm in its Konica Minolta form (the same lens in a different skin) on the new full frame Alpha 900 and you can see some test shots at:

http://www.pbase.com/davidkilpatrick/sony_alpha_900

i have included an example showing the vignetting and strong corner softening at 17mm wide open, but also results showing that f22 can be used on this 25.6 megapixel sensor for maximum depth of field without losing too much sharpness by diffraction; and that apertures like f8 and f11, in typical situations where a 17mm is used (105° angle of view), will give professionally usable results.