Alot of questions already regarding these two but none very conclusive for me. I've a nikon D3100 and going to replace my default kit lens with any of the below two -
1. Tamron SP AF 17-50 mm f/2.8 XR Di II LD Aspherical (IF)
2. Sigma 17-70 mm f/2.8-4.0 DC Macro OS HSM
I hear the old tamron (non VC) is alot better in terms of sharpness than the new VC one. Also hear the sigma does a front/back focus on canon mount...what about nikon mount..any experience?
My requirement is to have a good general purpose lens which can product very sharp images with decent focus.
Below are the pros and cons..I picked up from lenstip (I know people can check themselves but seeing in one place makes for better understanding. Plus these two lens seem to be hard choice for most users)
Tamron SP AF 17-50 mm f/2.8 XR Di II LD Aspherical (IF)
great sharpness in the middle of the frame at all focal lengths and diaphragm ranges
very good picture quality on the edge of the frame (except f2.8 )
good performance against bright light
good autofocus work
good build quality
visible chromatic aberration
vignetting at the whole focal length range (although the vignetting is even bigger for competitors at the same price range,)
visible coma at f/2.8
Sigma 17-70 mm f/2.8-4.0 DC Macro OS HSM
decent quality of build,
sensational image quality in the frame centre in the 17-28 mm focal lengths range,
very good image quality in the frame centre at longer focal lengths,
useful image quality at the frame edge,
efficient image stabilization,
chromatic aberration well corrected in the middle of the range and at longer focal lengths,
quite well corrected coma,
correct work against bright light,
relatively silent and efficient autofocus.
combination of maximum relative aperture and maximum focal length is not very useful,
visible vignetting in the whole focal lengths range.
Even with all this, I still cant make up my mind.
For me the OS seems to make a bit of difference effecting my decision...
But would like to hear your opinions based on your usage regarding these two lens.
These two lens seem to be the most widely preferred cheap upgrade from kit lens and lets put some perspective on them..