Tuesday, October 7, 2008
Time For Your Close-Up
More Macro • Matching Backups • Image Card Rescue The Best ƒ-Stop • Glass Beads Vs. Matte • Live View NewImage Card Rescue
Q) A friend went to a drugstore to have photos printed. She put her card in the machine and it broke the card. Do you have any suggestions on how to recover the photos on the card?
Via the Internet
A) I’m not sure what you mean by “broken,” but I’ve never seen a card that couldn’t be coaxed to give up its data as long as it was still intact enough to be inserted into a card reader. Whenever you have a card that won’t read, try it in different card readers; one might be able to access the information. If the information is there but can’t be read, there are programs that may slowly rebuild and extract the data. The software I use to extract data from a reluctant or inadvertently erased card is Image Rescue 3 from Lexar Media (www.lexarmedia.com). Google “CompactFlash Card Data Recovery” and/or “broken CF card” to find a host of methods and companies specializing in all kinds of media cards. If the card is physically broken and won’t read in any card reader, you’re going to pay a dear price to recover the data.
The Best ƒ-Stop
Q) How do I know what’s the best f-stop to use for each of my lenses?
A) There’s a general rule that using a setting approximately two ƒ-stops smaller than the maximum aperture of the lens will give you the best quality. An example would be an ƒ/5.6 lens set to ƒ/11 for the best results. Stopped down, the image quality will improve in several ways. The center and edges will be sharper; with wide-angle lenses, the light falloff to the edges will be diminished; and chromatic aberrations (color fringing) will be reduced. A lens that has a large maximum aperture, such as ƒ/2.8, may need to be stopped down more than two stops to use it in the ƒ/8 to ƒ/11 area—the sweet spot for most lenses.
We often use ƒ/16 when we need maximum depth of field and are willing to compromise a little bit on sharpness. But if you stop down even further, to stops such as ƒ/22 and, if possible ƒ/32, you’ll see degradation of the image that’s far worse than photographing wide open. Yes, you’ll get more depth of field, but the overall image will become soft due to diffraction.
Glass Beads Versus Matte
Q) Our club just got a new digital projector. The images don’t look very good on the screen we used for slide projection. Is there a special screen needed for digital projection?
Via the Internet
A) Most screens you purchase today are designed for digital projection. They usually have a matte surface that doesn’t scatter the light the way a glass-beaded screen does. The old lenticular-surfaced screens that worked fine with slides give a pixilated impression with digital images. A number of new technologies can be applied to digital projection. If you have a smooth wall, you can paint on a surface that serves as an ideal screen (see www.paintonscreen.com). Gray screens offer a slightly less-bright projection but heighten contrast. These screens absorb ambient light better than a white screen and improve the whites and blacks in a room that isn’t completely dark.
Be sure to buy the largest screen your organization can handle (both from financial and spatial considerations). Your digital projector is capable of much larger imaging than your slide projector could adequately project. My Canon Realis SX6 has no problems filling a 30x40-foot screen—when I can find one.
Live View New
Q) I have this feature in my new D-SLR camera called “Live View.” Why is this so special? I’ve been looking at the same thing on the back of my digital point-and-shoot for years.
A) Yes, a kind of “live view” has been a nifty feature on point-and-shoots from nearly the first digital cameras. The viewfinders on those cameras weren’t looking through the lens. Instead, you either viewed your subject through a small, optical window next to the lens, or you looked at a small LCD screen in the viewfinder that duplicated the larger screen on the back of the camera. More recently, the viewfinder on digital point-and-shoots has been eliminated completely.
The reason you haven’t been able to view live TTL previews on the back of a D-SLR (until now) is the nature of the single-lens-reflex system. The mirror directs the light to the viewfinder for previewing, then to the sensor for capturing the image. Live View is accomplished by a video feed that diverts the viewfinder’s information to the LCD screen on the back of the camera.
Since it’s a video feed, that image can be transmitted to another off-camera screen (even wirelessly) for remote viewing. This is a great advantage when you want to work in the studio with an enlarged version of your image for critical focusing and composition, or if you can’t directly monitor the camera, such as a remote positioning on a nest or a high-magnification setup. For these kinds of complex photographic tasks, Live View is indeed a great new tool.
For information about upcoming seminars and digital-imaging workshops, visit www.geolepp.com. If you have any tips or questions, address them to: OUTDOOR PHOTOGRAPHER, Dept. TT, George Lepp, 12121 Wilshire Blvd., Suite 1200, Los Angeles, CA 90025-1176 or online at www.geolepp.com.
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