Parish Church
Copyright © 2007 Nick Hudgell
Camera: Canon EOS 350D
Lens: Sigma 18–200mm f3.5–6.3 DC
Filter: UV
Date: 18th Feb 2007
Location: Parish Church, Leamington Spa
Focal Length: 18mm (equivalent focal length: 30mm)
Shutter: 1/400s
Aperture: F/10
ISO: 400
White Balance: auto
Comments: Whilst being one of my favourite photos at the moment, it gives a clear example of the barrel distortion you get on this lens at the wide angle. It’s not so evident with further zoom, but is a bit rediculous really!
Post–processing: none
John Rawnsley
... and chromatic abberation :)
I’ve got the Sigma too. :(
14 Mar 2007, 15:38
Max Hammond
It’s not possible to see from this image wheter there’s barrel distortion, because there’s a strong convergent distortion caused because the sensor isn’t parallel to the subject; that’s a fundamental property of wide-angle lenses, not an issue with this one. Cameras with “movements” (and shift lenses for SLRs) can point up without this effect.
If you want to look for barrel distortion, take a shot of a grid of parallel and orthogonal lines, which is itself parallel to the sensor plane.
There might be a hint of pincushion or barrel distortion, but nothing major. Fix the converging verticals and it looks fine, eg:

14 Mar 2007, 21:45
Ah! There’s my niaveness (spel?!) coming out! Awesome!
15 Mar 2007, 08:32
dj
Naivety. I like this picture a lot.
15 Mar 2007, 12:11
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