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
Stopped-Down Metering And FocusingWhen 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.
Adapters And HD Video
Professionals using a DSLR to shoot HD video are likely to be attracted to adapters. Most modern DSLR lenses are the products of the evolution of autofocus and the particular requirements of still shooters. Modern AF lenses weren’t designed for smooth and easy manual focusing like the older manual-focus lenses were. Film-era manual-focus lenses, particularly prime lenses, typically have focus rings that are geared in such a way that makes the process of doing precise, manual pull-focusing easy. This makes older lenses ideal for HD video DSLRs. Plus, most DSLRs don’t have all of their advanced automatic functions available in video mode, so the loss of features when using an adapter is negligible.
Electronic LinksWith 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.
Page 2 of 3