04-19-2012, 06:34 PM
[quote name='popo' timestamp='1334853564' post='17618']
If one side of the image is noticeably soft, that was a lens flaw and you should have got it checked out under warranty.
Putting that aside, stopping down generally helps up to the point where diffraction softening takes over, and further stopping down just makes everything softer. But you're trading against depth of field when you do so. You need to decide where that point it. Best way is to try it yourself. Try using f/5.6, f/8, f/11, f/16 on a scene and compare them.
[/quote]
Thank you popo, I'm assuming that this is a definite flaw in the lense and I should have got it sorted. I have attached an example photo, I have re-sized to 1600px wide so that it meets the file size limit but other than that I have not edited anything. At 17mm and F14 I wouldn't expect the left (particularly the entire top left corner) to be so soft whilst the rest of the image appears fine. Next time the sun is out, I shall try some shots from back garden at different focal lengths and apertures to see whether I can spot any patterns and potentially rule out particularly bad areas from further shots.
Meanwhile, does anyone here have experience of the Sigma 8-16 f4.5-5.6 and the Tokina 11-16 f2.8? I have decided that if I do get a new wide angle lenses then it will probably be one of these two - I can't decide whether I want the crazy wide 8mm to have some fun with or whether I should settle for the faster Tokina which I assume would be much better for indoor photography.
If one side of the image is noticeably soft, that was a lens flaw and you should have got it checked out under warranty.
Putting that aside, stopping down generally helps up to the point where diffraction softening takes over, and further stopping down just makes everything softer. But you're trading against depth of field when you do so. You need to decide where that point it. Best way is to try it yourself. Try using f/5.6, f/8, f/11, f/16 on a scene and compare them.
[/quote]
Thank you popo, I'm assuming that this is a definite flaw in the lense and I should have got it sorted. I have attached an example photo, I have re-sized to 1600px wide so that it meets the file size limit but other than that I have not edited anything. At 17mm and F14 I wouldn't expect the left (particularly the entire top left corner) to be so soft whilst the rest of the image appears fine. Next time the sun is out, I shall try some shots from back garden at different focal lengths and apertures to see whether I can spot any patterns and potentially rule out particularly bad areas from further shots.
Meanwhile, does anyone here have experience of the Sigma 8-16 f4.5-5.6 and the Tokina 11-16 f2.8? I have decided that if I do get a new wide angle lenses then it will probably be one of these two - I can't decide whether I want the crazy wide 8mm to have some fun with or whether I should settle for the faster Tokina which I assume would be much better for indoor photography.