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Tuesday, October 23, 2012

Extend Your Range

Ordering Close Focus • Sign Here • JPEG Vs. JPEG • The Coolscan Dustup

Labels: How-ToColumnTech Tips

This Clark's nutcracker was less than 10 feet away from the blind where Lepp was photo­­­graphing with a Canon EOS-1D X attached to an EF 500mm ƒ/4L lens and an EF 1.4X tele-extender. In order to focus all this magnifying power closer than the camera/lens combination's normal range (14.75 feet), Lepp added Canon EF II 25mm and 12mm extension tubes between the lens and the tele-extender. The exposure was ƒ/13 at 1⁄250 sec., with an ISO of 800. No flash was used.

Ordering Close Focus

Q I know that extension tubes can help me to use my long lenses and tele-extenders while working closer to subjects. But I don't really understand the principles involved, nor the way to stack all the components in my camera/lens combination. How can I make this work for me?
G. Crider
Via email

A A tele-extender, when placed between the camera body and lens, multiplies the magnification of the lens to which it's attached. A 1.4X tele-extender attached to a 500mm lens yields an effective 700mm. A 2X tele-extender (sometimes called a doubler) yields 1000mm with a 500mm lens. These are standard techniques for filling the frame with a distant subject. But these combinations don't focus very close, so if you want to apply all that magnifying power to a subject that's fairly near—well, you can't. For example, the closest focus of the Canon EF 500mm ƒ/4L lens is normally 14.75 feet.

Adding an extension tube to the combination moves the lens element farther away from the sensor, which enables a closer focus. You should add the extension tube between the lens and the tele-extender for most effective results; the extension tube(s) allow the telephoto to focus closer, and then the tele-extender magnifies the image produced. The gain in close focus is considerable; with 37mm of extension between the lens and a 1.4X tele-extender, our Canon EF 500mm ƒ/4L lens can focus at approximately 9.5 feet.

I can't let any discussion of tele-extenders and extension tubes pass without the reminder that whatever you insert between the lens and the camera (and between the lens and the subject, as in filters) has the potential to degrade the image. So start with a quality optic, add quality accessories, and be sure that your tele-extenders and extension tubes don't interfere with electrical connections (communication) between the lens and the camera.

Sign Here

Q Where's the best place to sign prints? I've seen some signatures placed directly on the print and some on the attached mat. What would you recommend? Should the print be signed with a pencil or ink?
B. Crompton
Via email

A Different photographers have varying preferences about the location of the signature, and some galleries and museums may have strict rules. Here's what I do, and why.

A valuable print should carry the signature of the photographer no matter how it's framed. A mat is temporary, so if the signature is on it, the signature is temporary, too. And a signature that's placed in the margin—the white border area beneath the image—can be covered by a mat. So I always sign on the print itself, well within the image. I usually sign in the traditional right corner, which is where most people look for a signature. But if the balance of the composition, or the background, argues for a signature in the left corner, I'll go there. I don't want the signature to detract from the image, so I keep it small. At the same time, I want the signature to be readable and not hidden in some busy grass or brush.


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