Monday, October 20, 2008

Canon SX110 Review: lens distortion - lab tests and real world images

The SX110 has a 10x zoom lens. With such a wide range you might be concerned that image quality might be compromised either at the wide or telephoto setting. On the whole, however, image quality is good throughout the whole zoom range.

At right is the camera at its widest zoom. Some barrel distortion is visible (IE, curved lines which should be straight), but it's not bad. Note, however, that most cameras have this to some extent. On the positive side, the corners of the image are just as sharp as the center. Many cameras, particular more compact models, have blurry corners. Many Canon SD cameras exhibit this problem fairly clearly, such as last year's SD850IS. It's nice to see that the SX110 does not.

Next is the lens at the other extreme of the zoom range, in full telephoto. Here, there is no indication of the barrel distortion seen at the wide angle setting. Again, there is also no corner blur. Thus, the lab tests show that the lens performs quite well.  What of real-world shots, however? In particular, does the wide-angle barrel distortion show up in photos of the real world? See the next few pictures. 

In this picture, which is designed to highlight the problem, it is possible to see distortion. Even so, it's not nearly as obvious as in the lab test. Given that you are unlikey to take a picture like this unless you are trying to show off the flaws in the optics, it's not too bad.

This picture is perhaps more representative of the real-world images which would show off this problem. The support columns clearly bend out toward the middle, whereas in real life they are as straight as your typical 2x4. Whether or not you find this objectionable is really a question of taste, but I personally don't notice it unless I'm looking pretty carefully.

This post is part of a series that reviews the Canon SX110IS.

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