Advice on buying a new nikon lens please?
Hey guys I have a nikon d7100 and I'm looking at getting a new lens. I currently have a 50mm. I shoot newborns, glamour, family's and large groups. My budget isn't very high. It's only about 500. I have in mind the sigma 17-70 mm f2. 8-4 but I'm not to sure if it will give a good sharp photo. I haven't tried many lenses before so I can researching. And as we all know with lenses there's good and bad reviews on anything these days. Is anyone able to help me out here please? Just tell me a couple and I will do some research.
I have a D7100 and I have a Sigma 17-50mm f/2.8 for my "normal" lens for everyday use. It is a very good lens. I don't know if the 17-70 is as sharp as the 17-50, but I can say that the 17-50 is an excellent lens. And the 17-70 is not as fast (f/2.8~4 vs the 17-50 constant f/2.8).
http://www.althephoto.com/lenses/sigma17-50.php
For portraiture, I have the Nikon AF-S 28mm f/1.8, the Nikon AF-S 50mm f/1.4, and the Nikon AF-S 85mm f/1.
I use the 28mm for group shots, the 50mm for full body shots, and the 85mm for portraiture (facial areas). Nothing beats the 85mm for this kind of work, even on a cropped camera such as the D7100. You have to back up a bit, but the results are well worth it.
Nikon has these lenses on rebate right now.
Not sure if these are the range of lenses you are looking at or not. If you are looking for lens reviews, try http://www.dxomark.com/...omark.com/" class='ext_link'>http://www.dxomark.com/...omark.com/ as they show what each lens is like on your particular camera. The notion is if you take an individual lens, it might perform better on one DSLR vs. Another.
Say you have an older camera, it might not be worth buying a high performance lens, but if you have a premium camera, that same lens might perform better. The http://www.dxomark.com/ ratings will tell you this.
For example, you could compare the Sigma 17-50 f/2.8 on a D7100, a D90, and a D3000 and see how it performs on each. You might find the lens performs much better on the D7100 than the D3000, so it might not be worth upgrading from the kit 18-55mm if you have a D3000, and so on.
With the variety of shooting you do, I would want a zoom lens, such as the 17-70mm that you suggest. If sharpness was a major consideration I would get Lightroom or Photoshop and use the lens database to make corrections.
Go with the one that has the highest rating.
Like AWBoater suggests, the Sigma 17-50 f2.8 is almost the sharpest 24-70 equivalent (The Pentax DA* 16-50 has it) .
The Sigma 17-70 f/2.8 is not as sharp as the 17-50:
http://www.photozone.de/...a1770284os
Don't worry what photozone says in the conclusion inferring that its a consumer lens. There are professional L series, and Nikkor lenses which are deemed "Pro-level", but are still not as sharp as this 17-70. Typical bias from websites that have commercial ties with the big two.
The advantage of the 17-70 over the 17-50 will be the USB connectivity. If your lens front or back focuses, you can adjust it. If you get this issue with the 17-50, you'll have to send it in to Sigma. (Nikon hasn't got a comparable pro-level APS-C lens, just ones suitable for full frame)
Another option is to save your pennies and go for the Sigma 17-35mm f/1.8. Its apparently super sharp - prime lens sharp.