Sigma 17-70

[FunkyJam]

Hey, Im interested in buying this lense but there's something that Im not understanding. Is it 2.8-4 or 2.8-4.5? I've seen both.

Also, is the Tamron 17-50 2.8 a better option?

Thanks in advance.

[Mt Spokane Photography]

A Canon 17-55mm or 15-85mm is the best option.  There are different versions of the 17-70(OS and non OS, they are different optically).  As a low cost lens, its fine.  Some of the limitations that caused me to quickly upgrade to the Canon 17-55mm lens were

   Stiff focus ring, useless for manual focusing, which was my primary usage

   Very poor resolution at close focus distances, which was also my primary use (Product Photography with manual focus)

For normal photography using autofocus, it was fine.  Mine was the non OS version, the OS version is not noticibly better, just has OS and costs more.

I do not have personal experience with the other lens, but I do with the lenses I've mentioned.

Here are some normal images taken with my 17-70 a few years back on my 30D.

[ferdi]

There are indeed 2 Sigma 17-70mm versions:
1. Sigma 17-70 mm f/2.8-4.5 DC Macro
2. Sigma 17-70 mm f/2.8-4.0 DC Macro OS HSM
The first and older one has slightly better MFD, 0.22m vs 0.20m, and maximum magnification 1:2.3 vs 1:2.7. It is also cheaper.
The second and newer one has image stabilisation and ultrasonic focus motor for all mounts (previous model only had it for Nikon mount).

The Tamron 17-50 has constant f/2.8 aperture, which is a plus. Faster autofocus, slightly better build, smaller and lighter are other advantages. Sigma HSM is more quiet, has closer MFD (0.22m vs 0.27m), and of course 20mm extra range. ISO tests show that the Tamron is sharper in the centre wide open, but softer in the corners.

Which lens is better for you depends on your needs. I could live without VC/OS/IS, but noisy lenses (i.e. without HSM/USM) get up my nerves. Have you also considered the Canon 17-55 f/2.8 IS USM or is that lens beyond your budget?