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LifestreamI had this nagging feeling that something was wrong with the UV filters on my lenses. Since they were all bought for peanuts, or more to the point included when I purchased the lenses, I realized that there was a definite possibility that they were adversely affecting image quality and contrast. Googling the subject will bring you to one of two extremist views – namely that UV and skylight filters may cool or warm the image, and reduce light throughput but even cheap filters wont influence the image quality in a noticeable way … or that anything but the most expensive multicoated B+W will ruin your images.
So anyway, I did some preliminary testing using the Canon 70-200L lens at 200mm (f/2.8, 1/200, ISO400). Hoya filter to the left. No filter to the right. 100% crop from RAW files, opened in PS and each given a +1,30 exposure boost only.
Removing the filter also let in a bit more light or so it seems from testing in AV mode (shutter speed jumped from 1/160 to 1/200). It is also possible that the filter interferes with the AF and that this accounts for some of the fuzziness. Camera was obviously on a tripod, using a remote shutter and mirror lock-up. One focus point was selected and used for both images.
I certainly need to test this thoroughly using all my lenses and respective UV filters. Could be just coincidence and unscientific testing on my part. But I feel I am on to something here. It could very well be that I’ll have to toss all my filters on the garbage heap.
