Pictures By Alan

I took another ride to test out the Tamron 17-35mm f/2.8-4 ultra-wide zoom. A very inexpensive lens considering the range -- about a fifth the price of the similar Canon 16-35mm f/2.8 L -- I was not entirely sure what to expect, especially since I've read reviews that reported very poor extreme corner performance on full frame cameras like my 5D.

Some tests quickly revealed the truth. No doubt, the extreme corners are unusable with the lens wide open. But it really is the extreme corners; on a 4x6 print it would be the last 3/8 inch of the corner. Otherwise the performance is acceptable across the field, and the corners rapidly tighten up as the lens is stopped down, becoming acceptable at f/8 and continuing to improve down to f/16, when the diffraction limits prevent further improvement.

Other than that -- it has some distortion, especially at the wide end. There is some chromatic abberation. The color seems neutral. Contrast is fine. Resolution is very impressive at f/8. Flare is a problem when sun falls directly on the lens, and so far my sun-in-frame pictures have not been usable. But for the price, I'm not complaining. I can live with these problems.

This picture was taken at 17mm. It's an interesting look, very wide angle, much more so than the 24mm I'm used to. You can, without difficulty, photograph your shoes and the horizon while standing. The horizon is, in fact, a constant headache -- it's in practically every picture, and keeping it level is difficult to do.