Originally posted by normhead You sound like you might be a tamron 17-50 guy. Start with a zoom, go with a prime when you know what FL you shoot most.
Also never count out the DA 18-135. It's great trail lens. It's great all purpose lens, but probably not the best for interiors, but WR for hikes etc.
I like my 21 but it's not much better in the wide end than the 18-135 for low light. The 15 is worse than both of them. You have to use the Tamron 17-50 for that.
Indeed 21 is so weak that it barely matched 18-135?? Of course in the wide end.