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Wednesday, October 13, 2010

Give Film Lenses New Digital Life

Lens adapters let you use an almost limitless combination of older lenses, as well as modern high-tech models, on today’s most popular DSLRs

This Article Features Photo Zoom

The Sony NEX-5 (above) and Panasonic Lumix DMC-G2 (below) are just two of the new mirrorless interchangeable-lens cameras that have some useful benefits for pros. The limited number of lenses available from the camera manufacturers is expanded greatly through the use of adapters.

Another consideration is lenses that protrude into the camera body. If the lens you wish to use on your DSLR protrudes into the camera body, it could interfere with the SLR mirror operation. Such lenses shouldn’t be used with DSLRs (they could be used in Live View mode with the mirror locked “up,” but damage could occur if you or the camera lowers the mirror with the lens attached). Definitely always check with the manufacturer of the adapter you intend to use as to whether a specific lens can be used with a specific camera body using that adapter (and sort of “eyeball” it yourself before attaching the lens, just to be safe).

Stopped-Down Metering And Focusing

When you use a DSLR with a lens that was designed for it, everything is automatic. When you select an aperture for a shot, the lens aperture remains wide open for easier composing and focus-monitoring, then stops down to the selected value when you fully depress the shutter button to make the shot.

When you use a lens adapter, the linkage between camera body and lens is broken. The lens will remain at whatever aperture you set. So you’ll have to manually set the widest aperture to get the brightest possible viewfinder image for composing and focusing, then manually set the desired aperture for the shot. This is inconvenient compared to auto-aperture operation, but not a big deal with nonmoving subjects. It’s a bigger deal for action subjects. Back in the day, sports shooters generally worked wide open, in part, to get a fast, action-stopping shutter speed, in part, to have a bright viewfinder image to work with and also to avoid fooling with the aperture ring while shooting. One more thing to keep in mind is that some lenses change focus when stopped down. If your does, you’ll have to focus at the shooting aperture, even though that provides a darker image and greater depth of field, making focusing more difficult.

Focusing screens in manual-focus SLRs have focusing aids such as central split-image and microprisms. Focusing screens in DSLRs were designed for autofocusing, and show AF targets rather than such aids. So you have to focus using the plain screen area (unless your DSLR accepts interchangeable screens, and a screen with a split-image or microprism focusing aid is available). This further compounds manual-focusing difficulties. But it’s possible to focus accurately manually when using an adapter—it just takes practice. If your DSLR offers Live View operation, you can use the magnified Live View image for critical manual focusing.

Electronic Links

With most adapters, not only do you lose autofocusing capability, but you also lose the focus-confirm indication in the viewfinder. A few adapters come with chips that activate the DSLR’s focus-assist system, so the lamp will glow when you’ve achieved focus manually. If you’re into such things, you can even buy the chips and install them yourself.

Some lenses don’t have aperture rings—Nikon’s G series and Canon EF lenses, for example. Novoflex offers adapters for Nikon G lenses that provide an aperture-control ring so you can adjust apertures with them. (We don’t know of any adapters to mount Canon EF lenses on non-EOS bodies—the EF lenses’ all-electronic operation and slightly shorter flange back distance than other DSLRs essentially preclude their use on other DSLRs.)

Some adapters do retain full automation. For example, Olympus adapters that let you attach Four Thirds System lenses to Micro Four Thirds System cameras retain full metering and (in most cases) even autofocusing capabilities. Unfortunately, few other adapters for DSLRs do this.