Originally posted by kennyes I have the Pentax 18-135mm, Sigma 70-300mm, Pentax 50mm, Vivitar 28mm, and Rokinon 16mm f/2. Also a Pentax 18-250mm,
Originally posted by angerdan I'd go for the DA 16-85mm.
Originally posted by seventysixersfan Assuming you are not getting rid of any existing lenses, I'd go for the Sigma 17-50 because it does not overlap as much with your DA 18-135mm. I have all three lenses (Sigma 17-50, 17-70 contemporary, and DA 18-135), and I find that the 17-70 and 18-135 serve very similar purposes, although the 17-70 is a bit sharper and has the added advantage of being faster at the wide end. But my Sigma 17-50 seems sharper than the other two zooms and having f/2.8 at 50mm makes for some beautiful portraits and bokeh effects. I'm planning on selling my 17-70 contemporary sometime soon, as it's not being put to much use-- I take the 18-135 on vacation and when I need WR, compactness, and reach. I use the 17-50 at home, around town, and for everyday life events, as it's so versatile. It definitely is heavier and bulkier than the 17-70 or 18-135, no question about that.
I was tempted by the 16-85 mm two years ago because it's a good lens, but already having the Sigma 17-70 mm would have been a duplication, I gave up. Moreover, both the 16-85 mm
and the 18-135 mm have a maximum and minimum aperture of 3.5 and 5.6 so they are not very bright at the main focal length.
Ideal for wedding photos, "but not only" would be the 24-70 mm F/2.8 if you have a full frame, but it would only be a 36-105 in APS-C, strange zoom!
If you're allowed to get closer at weddings, 17-50 is fine for indoor photos, and working with ambient light or with those LED lamps that don't bother you
(they only turn on and off when you need them) is better than the flash that creates a hard light if you can't use it. It's Ok