Have a question about digital photography? Send it to me. I reply to as many as I can--though given the quantity of e-mails that I get, I can't promise a personal reply to each one. I round up the most interesting questions about once a month here in Digital Focus. For more frequently asked questions, read my newsletters from December, January, and February.
Photographing a TV Screen
Is there a way to take clear pictures of the television screen with a digital camera?
--Irene Kwik, Ottawa
You didn't say what kind of TV you have, Irene, but I assume it's a traditional CRT.
You can take photos of such a TV screen, but no matter how hard you try, they won't look awesome. That's partly because an image on a CRT screen is inherently low resolution, but also because you'll need to slow down the shutter speed to capture a complete picture, and that'll result in some blurriness. Since a typical TV refreshes the 525 lines on the screen 30 times each second, you need to set the shutter speed at 1/30 second or you'll only capture part of the scene. If it doesn't look right even at that speed, you can slow the shutter speed a little more, but remember that if it's too slow, you'll get obvious motion blur.
For more information --including how to shoot a LCD or plasma screen--see "Take Pictures of Images on Your TV."
Converting Old Photo File Formats
I have heard that to ensure you'll be able to open photographs when technology changes, you should always save your photos as TIFFs. What is this format? Can a JPEG be converted to TIFF?
--Claire Wilkes, Lakewood, Colorado
Actually, Claire, I think this is terrible advice. Whoever told you this should be rapped across the knuckles with a newspaper and not allowed to dispense any more digital photography tips.
TIFF is one of many digital photo file formats. It used to be somewhat popular, especially among professionals, since it's what's known as a "lossless" format--when you save a TIFF file, there's never any loss of image detail. JPEG photos, however, sacrifice some image quality every time you save them in order to preserve hard disk space. TIFF is not as popular as it used to be, mainly because many pros now work in their camera's high-fidelity RAW format and output the final image as a JPEG at the very end. Indeed, by sheer quantity of photos saved each day, JPEG is orders of magnitude more common than TIFF, and therefore more likely to be directly supported well into the future.
To answer your question, there's absolutely no reason to expect that TIFF will be any safer than JPEG after the Zombie Apocalypse, the Robot Apocalypse, or the Clone War Apocalypse. Yes, file formats sometimes fall out of favor, and 25 years from now we might not use JPEG anymore. But you'll be able to view JPEGs (and TIFFs) as well as convert them to other file formats for a very, very, very long time to come.
Full-Size Photos From Facebook
My children often post photos of our grandchildren on Facebook. I can copy these to my PC but they end up very small. Is there any way I can copy them to my PC at the same size as they appear on Facebook? I don't want to print them, just view them.
--Michael Williams, Wales
Unfortunately, Facebook has poor photo management features. Photo sharing sites like Flickr let you download photos at much larger sizes than they appear on screen, but Facebook resizes all photos to tiny, barely-better-than-thumbnail sizes. But even so, you should be able to download photos at the size you see on screen, Michael. To do that, just right-click the photo and choose Save Picture As in Internet Explorer (or Save Image As, if you're in Firefox) from the menu. That will let you store a copy of the photo on your computer at the same size that you see it in Facebook.
How do I shoot lightning with my digital camera?
--Lalit Jain, Orlando, Florida
Shooting lightning is all about making long exposures, Latit. Since you don't know exactly where lightning will strike, you should set your camera on a tripod, point it in the general direction of the storm, set the shutter speed to 15 or 30 seconds, press the shutter release, and wait with fingers crossed. To avoid overexposing the scene, you might experiment with covering the lens while you wait for some action. There are a lot of variations on this technique, but this should get you started.
Is it possible to get a double-exposed picture with a digital camera?
--Gene Patten, Maui
There are a few cameras that have a double exposure mode, in which you can capture two distinct exposures in the same digital image file. In general, though, the answer is no. Double exposures on a film camera happen when you don't advance the film between shots, so you're exposing the same physical stretch of film stock to light two or more times. Digital cameras work very differently, obviously--nothing has to "advance" to take the next picture.
It's a simple matter to combine two or more photos into a double exposure afterwards in your photo editing program, though. For advice on how to do that, see "How to Make Multiple Exposures."
Hot Pic of the Week
Get published, get famous! Each week, we select our favorite reader-submitted photo based on creativity, originality, and technique.
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.
This Week's Hot Pic: "Birds by Capitol Building," by Derek Lomibao, Urbana, Illinois
Derek writes: "This is a flock of birds passing by the Illinois state capitol building at sunset. I shot this photo with a Nikon D40 and a Sigma 18-200mm lens set to the full 200mm."
This Week's Runner-Up: "Mist Rising from Glassy Lake," by Carl Bandolshesr, Henrico, North Carolina
Carl says that he used a Nikon D40X to take this picture in early winter on Lake Gaston in North Carolina, as a heavy fog was lifting off the lake. He writes: "The water was unusually smooth. Normally fast flowing from the river flowing toward a downstream dam, on this particular day, the water was still and glassy, allowing for clear reflections off its surface."
This story, "Frequently Asked Photo Questions for March" was originally published by PCWorld.