melissa. wrote in post #2243995
With the Sigma 17-70, how would it compare to the Canon 100 f/2.8, which is a true macro? B&H and some nice rebates going on and if I get another lens from there I can have the 100 for $409...Just about $20 more than the Sigma. Now since the 100 is a true macro does this mean I cannot take zooms like the Sigma, or what?
Sigma has a magnification ratio of 1:2, which means a 2cm object can cast a 1cm image on the sensor. The Canon, being a a 1:1 macro will have a 2cm object cast a 2cm image on the sensor. Hence the magnification is twice that of the Sigma.
The Canon is a prime lens, so there is no zooming, so essentially you have a 160mm lens on a cropped sensor. Hence it of a limted use to macro and portraits mainly.
The Sigma is a zoom and you can use it for landscape/cityscape to portraits. It's range is what we generally call walking around range, and very versatile if you walk around and like to shoot stuff outside.
I'm not impressed by the Canon 28-105 as it's not wide on a crop sensor dslr and it's optics are not stellar.
For $700, I'd probably get a Sigma 17-70, about $340 at Tristate, for walking around and either a Sigma 105mm f2.8 macro or a Tokina 100mm f2.8 macro for just under $350-390 at Tristate as well.
That way for about $700 you can have a 17-70 for walking around and a 100/105macro for real macro work. Personally, I'd first get the 17-70 and see if you really want a 100mm macro afterwards.