Testing a new lens

schizophonic

schizophonic

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Ken
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I've had my new Sigma 10-20mm for a couple of months now and gone on holiday with it but was wondering if the lens should be as sharp as it should be.

This is my 2nd sigma and my 50-150 F2.8 has been amazing.

Apart from taking some general snaps, how can i tell its living up the ££££ i paid it?
 
I was always uncertain about my first sigma lens. I think it was a bad copy, but by the time I had decided it was too late. After contacting another member he said that his lens sharpness was improved with the use of a super coated UV filter.

I thought I had nothing to lose, so I did buy it and it has improved the sharpness. I'm not sure if its a Sigma thing or something. If you can, test another one in a shop or something to compare. Try a super coated filter and see if it does anything!

I hope this helps, sorry I can't say for certain without seeing. If I'm right thats part of the EX range, so it should be brilliant quality (I think the EX is the premium range [sorry if i'm wrong!])

If it is underperforming, if not take it back if you can, if not try a filter that is super coated (I got a pro spec one off ebay for £20) and if that doesn't work, maybe try sending it back to Sigma?
 
schizophonic said:
I've had my new Sigma 10-20mm for a couple of months now and gone on holiday with it but was wondering if the lens should be as sharp as it should be.
Click to expand...
What makes you think it might not be as sharp as it should be?
(Or are you just a paranoid schizophonic? ;))
 
The 10-20m lenses tend to be nice and sharp in the centre but not so sharp towards the edge which is natural in such a wide angle zoom.
 
if you are able to post a raw file or un processed jpeg with full exif data it would be easier to tell you if it is sharp or not.
 
It doesn't look too soft to me but a shutter speed of 1/15th is verging on too slow for handheld (was it ?), quite a bit of distortion at the outside too which is normal at 10mm.
 
That shot looks just about right for a superwide zoom to me. They just don't do sharp out of the camera. Despite what people like to tell me, I've yet to see a really sharp unprocessed shot from one. They cram so much onto the sensor and have to do some serious light bending to get it there and this is how they look.

The shots sharpen up to look OK and these clever little lenses open doors that we couldn't even see through otherwise,
 
Looking at the file it is clear that the details are rather soft. But they are not overly soft. RAW files, no matter what camera system usually need post sharpening, saturating and sometimes a contrast boost.

As mentioned wide angles are not all singing all dancing optics. They need to bend a lot of light and the sensor needs to pick up a lot of data. The Sigma 10-20 is renowned for its center sharpness but this deteriorates greatly toward the corners. The below image shows you just how much.

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To read a full review of this lens click here.

The download you provided is also shot pretty much wide open (f/4.5). Most lenses will produce optimum sharpness from corner corner between f/8 and f/11. I personally wouldnt worry about it. Increase your aperture and apply post processed sharpening.
 
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