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What's on your mind? If you have a question about digital photography, send it to me. I reply to as many e-mails as I can, and I round up the most interesting questions about once a month here in the newsletter.

Want to read more FAQs? Check out reader questions from April, June, and July.

Who Needs Zoom?

I have a question about the need for zoom lenses for high-quality digital cameras with high-megapixel resolution. Cameras like the Nikon D80 are often packaged with a zoom lens. But since zoom lenses are heavier and produce less sharp images than a fixed focal length lens, why use a zoom at all? A simple and inexpensive photo editor could enlarge a segment of the image to give the same image as a zoom lens.
--Harris Barowsky, Cherry Hill, New Jersey

That's a great question, Harris. Personally, I'd love to dump my 500mm zoom lens, which weighs about the same as a small dog, and just use an image editor to "zoom in" digitally afterwards. Unfortunately, the laws of physics conspire against us.

There are two issues at stake here. First, a good-quality lens will produce a sharper image if you zoom in with the lens rather than cropping the photo with an image editor. Second, if you rely on cropping to do your zooming, you're discarding all the pixels you got when you bought your camera. If you crop an 8-megapixel image down to 2 megapixels, for instance, you don't have enough resolution to print the cropped image at high resolution.

The bottom line? Yes, you do need a zoom to take high-quality photos, both now and for the foreseeable future.

Adding Resolution to a Photo

We recently went on vacation, and my daughter mistakenly set our digital camera to "TV screen" mode. That means we shot all of our pictures at 640 by 480 pixels, which I didn't realize until we tried to print them. Nikon says that I can only fix this problem with software. What type of software would you recommend to enhance these pictures, and is it really even possible?
--Chris Galloway, Portland, Maine

Wow, that's a bad break, Chris. This should be a reminder to everyone: Double-check your camera's resolution setting before heading off to vacation, a graduation ceremony, or some other one-of-a-kind event. The bad news is that there's really not a lot you can do. The camera captured only about 300,000 pixels of information in each photo, which is enough detail to print wallet-sized photos and not much else.

If you are adventurous, though, you might consider trying a program like Genuine Fractals. Genuine Fractals, a plug-in for programs like Adobe Photoshop Elements, might let you "fake it" well enough to try printing 5-by-7s or 8-by-10s. The program uses fancy mathematical algorithms to fill in missing information and print images at larger sizes than their resolution would usually allow. (I wrote about an earlier version a few years ago.) It's expensive ($159), but there's a 30-day free trial available so you can see how well it works. It's worth a shot!

Clearing the Air About DPI

I'd like to find out how to take photos at 300 dpi. After I download my photos to my computer, they all report in at 72 dpi. So I'm guessing that if I save them at 300 dpi they will get too small to be useful.... or will they? Can you help clear the air about this?
--Alicia Popper, UK

I'd love to, Alicia; this is one of my favorite pet peeves.

Camera makers and software companies alike seem to love to confuse people about dots per inch (dpi) and digital photos. The reality is that dpi is essentially meaningless. There's no such thing as a 72 dpi or a 300 dpi photo--at least not as long as it's stored on your computer. Dots per inch only has meaning when you are about to print, because combining the pixel resolution of the photo with a dpi setting determines the final output size. So a 3000-by-2000-pixel photo (that's 6 megapixels) will be about 10 by 7 inches when printed at 300 dpi. If you print it at 200 dpi, the resulting print would be 15 by 10 inches in size.

The moral of the story is that you shouldn't worry about dots per inch, even if a program assigns an arbitrary dpi value to a photo. On the computer, it doesn't mean anything. It's a tool for specifying print size. The only thing that matters on the computer is pixels.

Rotating Video

I took video of a dance recital while holding my camera vertically. Is there a way to rotate the video so it plays normally on my computer?
--Pat Franklin, via Yahoo

You're in luck! There are a few programs around that will rotate video, and one of them is Microsoft's Movie Maker, which comes with Windows.

To rotate a video, just import it into Movie Maker and drag it to the timeline. Then choose Tools, Video Effects from the menu. Depending upon which way you held the camera when you filmed the video, drag the Rotate 90 or Rotate 270 video effect onto the clip in the timeline. Save the movie, and it'll render correctly.

Hot Pic of the Week

Get published, get famous! Each week, we select our favorite reader-submitted photo based on creativity, originality, and technique. Every month, the best of the weekly winners gets a prize valued at between $15 and $50.

Here's how to enter: Send us your photograph in JPEG format, at a resolution no higher than 640 by 480 pixels. Entries at higher resolutions will be immediately disqualified. If necessary, use an image editing program to reduce the file size of your image before e-mailing it to us. Include the title of your photo along with a short description and how you photographed it. Don't forget to send your name, e-mail address, and postal address. Before entering, please read the full description of the contest rules and regulations.

Boris says that he used a Canon 5D and an infrared filter to capture this surreal image of a local city park.

Yvette writes, "I took this picture during a storm in Glacier National Park in Montana. I used Photoshop's screen and multiply effects to make the image look even more eerie."

See all the Hot Pic of the Week photos online.

Have a digital photo question? Send me your comments, questions, and suggestions about the newsletter itself. And be sure to sign up to have the Digital Focus Newsletter e-mailed to you each week.