Do I have a bad Sigma 10-20mm for Nikon, excessive distortion?

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zeroeseight

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Wilson
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I recently took some photos with my new Sigma 10-20mm lens.

http://www.zen22161.zen.co.uk/Waterfront/Waterfront2.jpg

I know you are meant to get distortion at wide angle, but I don't really have enough experience to make comparisons. The above picture was taken at 10mm, the pillar under the sun and the Liver buildings are noticeably leaning. Do you think this is excessive distortion? Is it a bad lens that I should look into getting replaced or am I being unnecessarily worrisome?
 
No it's not a bad lens.

You can buy software called PTLens from http://www.epaperpress.com/ which will help to minimize distortion from pretty much any lens. They do a trial version so you can check it out.
 
With these massivley wide-angle lenses, you have to keep the camera and lens exactly level, otherwise you will get distortion. You actually get this with all lenses, its just more noticeable with exagerated wide-angle.

The additional distortion you get on the exteme left and right in landscape view is just a trade-off you have to make. Get used to keeping 'close' objects away from the edges and more to the centre. :)
 
I cant even see any noticeable distortion there.........you should see mine!
 
Yep, PTlens, works a treat. I just tried it, but wont post as you haven't got editing ticked, but if you adjust the vertical by about +12ish, then a crop, you have perfect uprights. Of course the problem is you lose some of the width, so its a case of balancing natural wide angle distortion with how much correction you really want and how much pic you dont want to lose.
 
LadyLens said:
Yep, PTlens, works a treat. I just tried it, but wont post as you haven't got editing ticked, but if you adjust the vertical by about +12ish, then a crop, you have perfect uprights. Of course the problem is you lose some of the width, so its a case of balancing natural wide angle distortion with how much correction you really want and how much pic you dont want to lose.
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Ahh - there speaketh my PT lens disciple :D
 
Cant you just use the skew tool in Photoshop?? :shrug:
 
Yes Janice but PTLens adjusts the image by different amounts across the whole area to more accurately compensate for the different levels of distortion.
 
LadyLens said:
:D indeedeth!


Although the preset sigma10-20 wasnt enough, hence the vertical adjustment. and YES, I still find myself gawping at verticals/horizontals, and its all YOUR fault :nuts: :lol:
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lol - i seem to have communicated that issue and am now cured :) (almost).........

The lens correction under the distort tool in CS2 and CS3 is excllent for adjusting the image further after PT has worked its magic. Whereas PT works to a preset calculation, the CS tool allows you free-reign in adjustments :)
 
Folks thanks for allaying my fears :love:, I feel much better now. The lens correction software would not have worked so well on the image I posted as I just realised it was a cropped image. But even so the image had already gone through a LensFix filter, so I will give the other software/techniques mentioned a try.


Jonnyreb With these massivley wide-angle lenses, you have to keep the camera and lens exactly level, otherwise you will get distortion. You actually get this with all lenses, its just more noticeable with exagerated wide-angle.
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I think you are right here, the camera was not level as I had angled it downwards to include the sand in the foreground, thanks.
 
LadyLens said:
You just didnt want to get wet knees in the sand did you?!? :lol: :lol:

Glad you sorted it. ;)
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Hehe, only just bought the stuff so didn't want to get too near to the elements. Never occurred to me to use the vertical adjustment in the lens correction, it makes sense now see that I had angled the camera downwards, it looks so much better now, cheers :)
 
Its the lens :)

IMG_8573-159_1-157_2-158-21.jpg


See :) The closer you get to something the more distorted it'll be.
 
Thanks for the examples, will have to give that nshift a go some time. Inherently I knew to expect heavier distortion at closer ranges, I was just freaking out at seeing it at that sort of distance across the Mersey. :lol:

Now I realise that I had confused perspective over lens distortion.
 
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