Hoystory reads

Matthew Hoy
By Matthew Hoy on July 29, 2006

I recently got some books in the mail, including Bryan Peterson's "Understanding Digital Photography." The book is a pretty good primer for those who've gone out and bought a new digital SLR. However, I would suggest that Peterson's "Understanding Exposure" book is the better buy if you're only going to buy one book.

Two notes on Peterson's newest book:

First, I got a little chuckle out of Peterson's instructions on how to remove dust from your camera's sensor. Some cameras, notably those made by Olympus (and the new Sony camera, though there are some questions as to whether the Sony version is as effective as the Olympus), don't require sensor cleaning, because they have a supersonic wave filter (SSWF) that does it for you.

Second, I got repeatedly frustrated with Peterson's misinformation with regard to the JPEG format. If you're doing serious shooting, I agree that you probably want to stick with the RAW format. However, Peterson falsely claims that because JPEG is a lossy format (that is, it uses an algorithm that tosses out pixels in order to shrink the file size thereby giving you less dynamic range in your digital images) that everytime you open and close a JPEG file, you decrease its quality.

I'm not reading Peterson wrong, he phrases it the exact same way repeatedly -- that opening and closing a JPEG file reduces its quality.

This is false. Every time you make a change to a JPEG file, whether it is simply to rotate or crop the file or a more drastic change like adjusting the hue and saturation, the quality decreases ever so slightly. However, merely opening a JPEG file to view it or print it or insert it into a Powerpoint slideshow, does not reduce the file quality. As long as you don't change the file, you can open and close it from here 'til kingdom come and you won't further reduce the image quality.

Frankly, it's a little surprising that no one corrected Peterson's error before it got into print.

If you ignore that one bit of technological ignorance, then Peterson's book can teach you some things.


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July 2006



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