Beginner Testing for barrel and pincushion

meddyliol

meddyliol

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Brian
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This might seem a daft question but what is a good way to test a lens for barrel & pincushion?

Thanks

Brian
 
Just about every lens has already been tested and can be found on the web tests.
However Shooting graph paper shows it up at short distances.

More and more modern lenses rely on camera firmware to do the final corrections. so although the lens might suffer from either, or both if it is a zoom lens, the chances are we are never aware of it.

Shooting a modern frame office building square on shows it up well if enlarged to 100%
 
OK, thanks
 
Do yourself a favour and don't get caught up in the hunt for this type of thing. Unless, it's a really faulty lens, it can be easily corrected in Lightroom, Photoshop, etc.

There's enough to worry about when you take an image :D
 
meddyliol said:
This might seem a daft question but what is a good way to test a lens for barrel & pincushion?

Thanks

Brian
Click to expand...

Very easy. You can see it through the viewfinder. Just line up a straight edge against the long side of the frame, like the join/line between a wall and the ceiling, and there it is. Strong distortion is easily visible that way, but for more subtle effects, and things like moustache-shaped distortion, take a pic and view on the PC. Shooting something like graph paper, at close distance, will exaggerate distortion, as it often varies slightly with distance.

Wide-angles tend to have barrel distortion, sometimes quite a lot. Longer focal lengths show pincushion, and many zooms will show both flavours at different ends of the focal length range. Lens designers these days often don't worry about it so much as it's so easily corrected in software, sometimes even in-camera. This then allows more scope to improve other aspects of performance. To measure distortion, you really need software, eg Imatest.

Edit: what lens is it? You might well find the answer in one of the reviews here http://www.photozone.de/
 
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Also look at the Lenstip website - www.lenstip.com - lots of lenses tested including for optical distortion.

As mentioned above, most cameras now correct in-camera - but often only for JPEGs. RAWS that are uncorrected can be corrected in PP. There are lens profiles for hundreds of lenses in LR.
 
LeeRatters said:
I wouldn't really worry about it.
Click to expand...

that

the only test you need is - do my pictures look good

the rest of it is just so much pixel peeping
 
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