Originally Posted by k100d
the sigma is heavy because it is built well. the tamron 90 and the pentax dfa's pale in terms of build quality.
i'm a bit confused you're giving up the macro for a non-macro lens. i guess only the focal length was important and not the closeup ability :S ?
that's about it... if wanted the focal length and took the macro capability as a bonus. I doubt I'd use the macro on more than one out of 10 shots, so I'm guessing it adds weight and complexity without real benefit (for me). Also, are you saying the Pentax 70 isn't well built, or just not at the same build level as the Sigma?
FHPhotog