Tamron SP AF 11-18mm f/4.5-5.6 Di-II LD ASPHERICAL (IF) Reviews

I bought the Sigma 10-20mm lens from a local camera store, thinking it would probably be the best of the three ultra wide zooms available from Sigma, Tamron and Tokina. I was flat out wrong. You see, I also did an in store test of all 3 of these lenses when I made this purchase. I used my own camera; a Canon 10D. I was sure to use shutter speeds fast enough to not require a tripod and no flash for all the shots. For each lens I did an in the store shot and an 'out the window' shot. Granted, this test did shoot all the lenses at only the wide open aperture, but I figure that's how I'll most likely use the lens anyway. Yes, it's not a real scientific type of analysis, but I am confident what I saw did not lie to me. Here's my findings:

Tokina 12-24mm f/4.0:
This lens was the sharpest by a wide, wide margin. It showed tremendous detail where the other two lenses showed nothing. However, the chromatic aberation (color fringe) was also tremendous. Yeah, I know the camera raw plugin has some capabilities to correct this, but one, I don't want to d*ck with every photo like that and two, I've found it doesn't do a completely thorough job as it will fix the problem in one are and introduce it in another. You just can't beat high quality glass that doesn't need Photoshop fixes. So this lens was a no go.

Sigma 10-20mm f/4-5.6 EX DC HSM:
This lens had the least chromatic aberation. However, the shots were noticeably softer. Compared to the other two lenses, it looked like I was shooting through a stackup of 3 or 4 uv filters. Photoshop sharpening did help, but it can't change the fact that detail that wasn't there to begin with, isn't going to magically show up from any amount of sharpeing. I originally bought this lens, but returned it after I reviewed my test images and went back to get the Tamron.

Tamron 11 - 18mm f/4.5-5.6 XR DI-II LD:
Granted, this lens costs about $100 more than the other two, but to me this lens had the best comprimise of sharpness/ resolving power and least chromatic aberation. I've had it for a few months now. It does seem to hunt a bit for focus, which I guess I can live with. I didn't use the other two lenses enough to tell if they had this same issue. Perpahs they don't as they both are f/4 and this lens is an f/4.5 at the wide end.

I have had this lens for two years now on a Nikon D70s. I have also had a Sigma 10-20mm for a while which I felt was inferior to the Tamron (I sold the Sigma eventually).

Pros
- Better optics (compared to Sigma)
- Much lighter and in my opinion, "feels" better.

Cons
- No good for night handheld shots (only f/4.5)
- AF very slow and hunts