Originally posted by twitch I thought the old Sigma 18-50 was inferior to the Tam 17-50, .....
Most reviews say the Tamron is a bit better/sharper than the Sigma,
but having owned a Sigma 18-50mm f2.8 EX DC MACRO for a year or so
and shooting mostly wide open/night shots, out of curiosity I did buy a Tamron
a few months ago to compare performance and determined they were just about equal. (tested copies anyway)
What is not equal is the build quality and materials of the Tamron, it felt/handled like a plastic toy compared to the Sigma.
Had I noticed any low-light / sharpness improvements over my Sigma I surely would of kept the Tamron
since 95% of my shots are at night/f2.8 but returned it to store after a few days of testing.
Michel