TECH Q AND A: How do I change the focus on a digital SLR?
Sound Advice: Technology Q&A By Q. My boyfriend used his digital SLR to take a really nice picture of my nephew standing by a fence. What made it look so nice was my nephew was in focus but the background was fuzzy and soft. How can I do this...
Sound Advice: Technology Q&A
Q. My boyfriend used his digital SLR to take a really nice picture of my nephew standing by a fence. What made it look so nice was my nephew was in focus but the background was fuzzy and soft. How can I do this when I take pictures myself?
--C.S., Washington, Pa.
A. You can control how much of the foreground and background is in focus (called "depth of field") by changing combinations of zoom and aperture lens settings.
Wide-angle lenses and zoom settings create lots of depth of field, as do small f-stop settings. Though called "small" because the lens iris is small, this corresponds to the higher numbers.
Telephoto lenses and zoom settings, as well as larger f-stops, limit depth of field. So, to create a portrait with your nephew in focus you would set you lens at a telephoto setting and use the lowest f-stop that you can for the lighting conditions.
A few other tips will help you make the most of these settings. The closer you are, the less depth of field you have. If you are only a foot away from your subject even if you use the smallest f-stop on the widest lens setting, you won't have much depth of field. When photographing a group always focus one-third of the way in. Obviously, you will want to use a wide-angle lens setting and a smaller f-stop to maximize depth of field and get everyone in focus.
A final note: The size of a camera's sensor has an impact on depth of field. Larger sensors have less depth of field and very small sensors have tremendous depth of field. Digital SLRs and Micro Four-Thirds cameras have large enough sensors that you can exercise considerable control over depth of field since their size makes them essentially a blank slate, leaving it up to your lens and aperture to determine depth of field. Most compacts have tiny sensors that have so much depth of field that you get most everything in focus no matter what you do, unless you have an ultra zoom camera and use it towards the end of the zoom range. If you have a compact you may not have adjustable f-stops anyway, so just use the portrait setting for portraits and use the zoom at the end of its range if you want to make a fuzzy background.
Q. I want to replace a single-disc CD player I use in an audio-only stereo system. Why don't I see component CD players for sale in big-box stores anymore? Don't they make them anymore?
--G.M., Atlantic City, N.J.
A. You can still buy a simple CD player but you won't usually find them in mass-market stores. Because Blu-ray players and DVD players also play CDs and you can get a DVD player for under $50, there isn't much incentive for manufacturers to make CD players for the mass market. Even if you only plan on using the CD-playing functionality you are better off having the DVD playback available if you need it.
Some audiophile brands still manufacturer dedicated CD players, but they cost much more than a typical DVD player or even s Blu-ray player found in a big-box store. You can find them in specialty hi-fi stores and online.