Sharpness of Lenses

skankmaster · 25 Nov 2006 at 10:38

Thinking about a len for photographing people. Would I get similar results if using a wide angle ~25mm, versus say a 50mm or 85mm from further away, or would a lens with a narrower range always be sharper in general. I ask this, as I was looking at a 17-40L or a 85mm. The 85mm worked out a bit cheaper and is in a range I dont have yet. Thanks.

rpstewart · 25 Nov 2006 at 10:47

Sharpness isn't really a function of focal length, you can get WA lenses that are sharp all through the aperture range and you can get ones that aren't.

I wouldn't take portraits (head & shoulders shots) with anything less than a 50mm lens really, any shorter and you have to get so close to fill the frame that a) it's uncomfortable for the subject and b) you'll start getting distortion of the image due to the short focal length.

Most portraiture seems to be done in the 50-200mm range, as you go towards the longer focal lengths you can get a more defined depth of field coupled to the perspective compression that comes with long focal lengths.

skankmaster · 25 Nov 2006 at 10:58

Thanks. In that case, it looks like its an 85mm prime for me. I considered a 70-200F4 but think maybe the prime is the better choice.

dod · 26 Nov 2006 at 09:12

Assuming it's the F1.8 you're looking at it's a cracking lens.

Joe T · 26 Nov 2006 at 09:43

As said above, focal length isnt a good indicator of sharpness. Primes will generally be sharper than zooms. And lenses costing more £££s will generally be sharper. There are exceptions to every rule though.