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08-31-2013, 02:38 PM   #1
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Strange distortion on 18-135 at 40mm

Hi,

I've attached a photo with strange distortion of the horizon at the top of the image.

The photo was taken on a K5 with 18-135 lens at 40mm F7.1 1/800 ISO100

Any comments or opinions will be helpful.

Is this normal? I thought that at 40mm which is 60mm on 35mm format gives you a perfectly flat horizon and on this photo it is bending the wrong way. The curve should bend the other way if my math is correct!

Cheers
Frank.


Last edited by FreeSpirit9; 06-29-2014 at 03:32 AM.
08-31-2013, 04:33 PM   #2
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It's pincushion distortion and correctable in PP. It's not uncommon in lenses and most lenses are tested for it. I don't know if it common in that lens or you have a bad copy. I'm sure others will chime in.
08-31-2013, 04:40 PM   #3
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QuoteOriginally posted by Francisco Quote
Hi,

I've attached a photo with strange distortion of the horizon at the top of the image.

The photo was taken on a K5 with 18-135 lens at 40mm F7.1 1/800 ISO100

Any comments or opinions will be helpful.

Is this normal? I thought that at 40mm which is 60mm on 35mm format gives you a perfectly flat horizon and on this photo it is bending the wrong way. The curve should bend the other way if my math is correct!

Cheers
Frank.
This looks normal to me. You can have your camera automatically correct this type of distortion (in the JPEG files it produces) by enabling the distortion correction option through the status screen.

This type of pincushion distortion is always going to be the most pronounced near the edges of the frame.

Adam
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08-31-2013, 05:20 PM   #4
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OK, that's good to know.

Thanks to you both.

Cheers.

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