Sigma 10-20mm 4.0-5.6 test shot whadda ya think

[ajrobertson]

<p>As this is my first wide angle lens, I was hoping some would let me think of the copy quality, and if it seems to be calibrated well for my 40d body.<br /> <img src="http://d6d2h4gfvy8t8.cloudfront.net/10363653-md.jpg" alt="" width="680" height="453" /><br /> I put it through the unsharp mask filter at 80% .5 radius threshold 3 I used the AF centre spot on the 2 triangular ice chunks dead center. Made sure there was a little flare on the top left. It was taken at 10mm F10 1/500sec.<br>

<br /> It seems to be relatively sharp in the centre and losing it on the edges, I think there is some CA as well... all as advertised. I will be using this for landscape wide shots so i am trying to compare this apples to apples in reference to my other lenses in which on closer shots is no comparison in sharpness.<br /> cheers,<br /> Andrew<br>

p.s how can I export from either lightroom or PS 4 so that the EXIF data is preserved when I upload to this site? I think I asked about this before but need some help.</p>

[tom_harvey3]

<p>Looks good on a 15.6 inch laptop screen to me. You have to remember to take it easy with the unsharp mask filter.....when you can notice the result yourself, then it may be oversharpened.</p>

<p>I have the 10-20 myself and love it...used it all through the southwest US last April and will be doing it again in April 2010. Remember with this lens, diffraction can show its ugly head since f/10 is a pretty small diameter opening at those focal lengths.</p>

<p>I found myself a 3-axis hot-shoe mount bubble level for shooting with that monster, since corrections in PP for WA distortion cost you a lot of image area.</p>

[ajrobertson]

<p>if i understand correctly, if you aren't completely level, the distortion effect of straight lines around the edges of the frame is exaggerated?</p>

<p>cheers and thanks for the response and tips! </p>

<p>andrew</p>