Frequently Asked Photo Questions for August
Have a question about digital photography? Don't keep it to yourself. 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 this newsletter.
Shutter or Aperture to Freeze Water?
In "Freeze Water in Flight," you explained how to capture the moment a water balloon bursts. You suggested using aperture priority mode. But why not use shutter priority and set it to the highest speed possible?
--Carrie Chase, Essex Junction, Vermont
That's a great question, Carrie. The reason I suggest using aperture priority is that in many cameras if you set a high shutter speed in shutter priority mode, the camera will take the picture using that setting even if it results in a underexposed picture. In other words, many cameras don't limit your shutter speed choices to those that match available aperture settings.
But if you choose the biggest aperture setting available in aperture priority mode, you'll always get the fastest possible shutter speed while maintaining a correct exposure. As a result, it's a more reliable setting for high-speed photography.
Choosing a Disc
I took some short videos using my digital camera and then uploaded them to my computer. I would like to copy the videos to a disc so I can share them with other computers. What kind of disc do I need? CD-R, CD-RW, something else? There are so many types it's very confusing.
--Crystal Dover, Chicago
The simplest solution is to always stick with CD-Rs, Crystal. These discs are not erasable or rewritable, so you can fill them up with files only once, but they're compatible with virtually any computer. Rewritable discs like CD-RWs are less compatible, and sometimes you need special software (like Roxio Easy Media Creator) or a newer operating system (like Windows Vista) to read and write files on them.
How do I digitalize old film 35mm slides to DVD?
--Gene Mandel, Glendale, California
First, scan the slides to your computer; then copy them to DVD using a disc burning program.
Many flatbed scanners have slide scanning attachments, or you could opt for a dedicated film scanner that is optimized for the task. You can scan the slides as high-quality JPEG files or, to preserve the full scan quality, try PNG or TIF format.
From there, you'll generally need to use a common disc burning program like Roxio Easy Media Creator or Nero. If you have Windows Vista, there's no need for extra software.
Upsizing and Downsizing
I like the idea of shrinking photos before e-mailing them, but I have a few questions. For example, I generally resize the larger dimension to 800 pixels, and I set the image quality when I save in JPEG format at level 8. Why do I do this? Because someone once told me to. Are those really the optimal settings? Also, If I accidentally save a photo at 600 pixels instead of 800 and realize the error later, can I reopen the picture in Photoshop Elements and resize it to 800?
--Dick Wexelblat, Clarksville, Virginia
You asked a surprisingly complicated question, Dick.
When it comes to sizing photos, there's really no such thing as an "optimal" setting. If you want to shrink them down for e-mail, 800 pixels on the long edge is not a terrible rule of thumb--but on its own, it really doesn't make much sense.
Here's what I'm talking about: When you send a photo in e-mail, the e-mail program, your ISP, and the Internet in general do not care what the physical dimensions of the image are. The only thing that matters is the file size--something I sometimes call the "weight" of the image. Many ISPs block attachments larger than a certain size. Depending upon the ISP, that might be 1 megabyte, 5 megabytes, or even 10 megabytes. If you know you can successfully send (and your recipient can receive) e-mails with 10-megabyte attachments, and if you're only sending a single photo, you don't need to resize the image. But if you're trying to send ten photos at once, you probably need to resize them. And picking a dimension out of the air--like 800 pixels--won't do you much good if the total attachment size still turns out to be too big for the ISP to handle.
All that said, if the only thing you want to do is make photos smaller so they transmit faster, then 800 pixels is a good choice because it's big enough to mostly fill the computer screen, but dramatically smaller than the full size that your camera originally captured.
Here are some more observations, if you can stand them: Don't change the quality setting. In Photoshop Elements, the maximum image quality is 12 (Corel Paint Shop Pro sets "best quality" at 1), and I recommend always using this value. Always. Don't throw away image quality, even if you're changing the physical dimensions of your photo. Changing quality adds ugly artifacts, blurs detail, and ruins colors. There's no reason to ever compromise image quality in a photo.
As to your last question, if you accidentally sized your picture too small, don't then resize it larger ("upscale" the photo). You've already discarded pixels of visual information; upscaling the photo can't add back that lost visual detail. All does is make the remaining pixels bigger in an effort to resize the image. The result is going to be a mess. If you need a larger photo, go back to your original image file (you did save the original, right?) and resize it accordingly.
Using a Gray Card
Can you tell me how one actually uses a gray card?
--Rex Koh, Elizabeth, New Jersey
Sure, Rex. A gray card lets you calibrate a digital camera so it properly exposes colors in a photo. It informs the camera where "white" is, so it can render all the other colors in the spectrum properly. While cameras are designed to perform an automatic white balance each time they take a picture, they're easily confused and you can often end up with photos that have unnatural colors.
You can buy a gray card at your neighborhood camera shop. To use it, choose your camera's white balance adjustment setting and then photograph the card while it mostly fills the frame in your viewfinder. Be sure to read your camera's user guide to find out exactly how this works on your camera. For the best results, have someone hold the card in front of the camera, in the location where you plan to shoot your photos. If the lighting conditions change, take a new reading off the card. Read more about this in "All About Color Balance."
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.
This week's Hot Pic: "Don't Let the Sky Be Your Limit" by Allison Scranton, Milwaukie, Oregon
Allison says that she took this photo at an sunflower garden in Troutdale, Oregon using a Nikon D70.
The addition of the Orton effect gives it an ethereal quality.
This Week's Runner-Up: "Snowed Out," by Jennifer Grim, Surprise, Arizona
Jennifer writes: "My husband and I were camping on our 2-year anniversary, and we woke up to find two inches of snow around us. Having prepared for 70-degree weather, we packed up and left for home. This picture was taken from the passenger seat of our vehicle on the way out of camp at Woods Canyon Lake, Arizona."
See all the Hot Pic of the Week photos online.