ISO Speeds
In the film world, if you want to take low-light shots, you can buy high-speed film—ISO 400 or 800, for example. Fast film allows you to take nighttime or indoor shots without the harsh glare of electronic flash.
Digital cameras allow you to adjust light sensitivity on a shot-by-shot basis. Switch the camera into one of its manual-exposure modes (a common mode is labeled P, for program), and then use the camera’s menus to adjust its ISO speed.
Note that shots photographed at higher ISO speeds—settings over 1000, especially on less-expensive cameras—are likely to have digital noise, a slightly grainy appearance. For me, it’s a happy trade-off: I’d rather have a sharp, naturally lit photo with some noise than a noise-free but blurry ...
Get iPhoto ’11: The Macintosh iLife Guide to using iPhoto with OS X Lion and iCloud now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
