p.1 #1 · Help pick a Lens Sigma 24-60 f2.8 or Canon 28-135mm IS
I am getting ready to buy a new lens to go along with my Sigma 70-200 F2.8 and Canon 85mm F1.8. I would like to be able to use the lens inside without a flash. I am not sure if the IS on the 28-135mm will be able to do as good a job in the low light as the Sigma 24-60mm F2.8. I understand the IS is suppose to be equivalent to a couple of F stops, but will I loose much of the DOF. The 24-60mm range fits my needs but the 28-135mm IS sure would be versatile and not sure which one will give me better images. Cost is always a concern but I think I can pick up either lens for around $325 or less. Thanks for any input.
p.1 #2 · Help pick a Lens Sigma 24-60 f2.8 or Canon 28-135mm IS
How about either of these Tamrons - 17-50 or 28-75? Both are f/2.8, and both will give much better IQ than either of the other two lenses you mentioned. The 17-50 is a bit more $, and won't work on a FF body, though.
