Hi,

I've been shooting with my trusty Pentax MZ-6/ZXL but I am finding that my wide angle 35-80MM FA (http://www.bdimitrov.de/kmp/lenses/z...-80f4-5.6.html) zoom cannot provide me with the consistant results I need. In particular, high levels of softness are obvious at 80mm, and a flat field of focus is quite hard to get. Barrel distortion is also a problem, especially as I wish to shoot a lot of architecture and landscapes.

I've got a budget of approximately £150 ($280), and I'll need a wide angle zoom lense that I can get reasonable 16-12inch enlargements (better then my current lense). I can live with a smaller widest apperture (F4.0-5.6) and would sacrifice faster f-stops for sharper images.

I've looked at the Tamron 28-105mm f4-5.6, and the Sigma 28-105mm f3.8-5.6 UC-III .

I can't seem to find anything that points to either one being better then the other. Nor can I determine whether they will be worthy enough over my 35-80mm to go out and by. Genuine Pentax gear seems harder to come by. I guess they're busy developing compact digital cameras rather then developing traditional film technology.

Thank you.