Plugged In: New look — Find deals, quality in existing lenses

By Joe Kashi, for the Redoubt Reporter

Our recent suggestions about using older, high-end lenses with modern cameras apparently struck a chord for readers who asked for more information.

The advent of mirrorless compact-system cameras opens up more opportunities to mix and match many of the best older lenses from a variety of makers with modern digital cameras, using a variety of adapters. This often, though not always, results in improved image quality and lower costs. Here’s how and why.

In order for any lens to focus distant objects clearly, that lens must be able to achieve a specific minimum distance from the film or sensor, a distance that’s specific to each lens. If the rear of the lens can’t get close enough to the sensor, then sharp focus will be limited to very close subjects. That’s termed optical “infinity,” a focus distance that’s usually about 20 feet or less for most lenses, rather different than true infinity.

Because CSC bodies are so thin, there’s usually more than enough distance to use a mechanical adapter that properly spaces and mounts older, film-era and current dSLR lenses at a total length that allows sharp focus at optical infinity. That’s because those adapted lenses are designed for moving-mirror SLR cameras.

Moving-mirror viewfinders, still used in current dSLR cameras made by Canon, Nikon and Pentax, require a lot of front-to-back room in order to flip up and expose the film or sensor without hitting the lens. That in turn forces lens makers to design both film and dSLR lenses to achieve optical infinity focus while quite a distance in front of the film or sensor. That longer rear focusing distance in turn results in physically larger lenses.

CSC cameras can use such a wide variety of lenses from different makers because they avoid the problems inherent to moving-mirror cameras. There’s nothing between the lens and the sensor. That means that CSC lenses have no rear distance limitations, allowing more straightforward optical designs that often produce better results at lower cost, using physically smaller lenses.

Many older film and SLR lenses are quite sharp, though not as consistently so as modern optics. Because all SLR lenses require a greater distance between the sensor and the rear of the lens, it’s easy to find mechanical adapters that properly space them while maintaining infinity focus.

Older, full-auto Four-Thirds lenses made by Olympus and, to a lesser extent, Panasonic, are often exceptionally good, even by current standards. These lenses were made within the past decade for moving-mirror, prograde cameras, and thus also require greater distance from the sensor. They retain complete autoexposure and autofocus compatibility when used with smaller, current, Micro Four-Thirds cameras that eliminate moving mirrors.

That makes Four-Thirds lenses easy to adapt to current Micro Four-Thirds cameras. I use Olympus’ MMF-3 adapter because it’s weather-resistant as well as retaining full auto capability with older, Four-Thirds lenses. Autofocus speed is very fast with Olympus’ newest prograde camera body, the OM-D E-M1, but rather slower with other M4/3 cameras.

I’ve personally found two Four-Thirds lenses to be exceptional values. Olympus’ 50-mm f/2 macro lens acts like a bright short telephoto lens. It’s so sharp that it exceeds the sensor resolution of current M4/3 camera sensors and is still used by professional reviewers when testing new M4/3 bodies. It’s weather-resistant when used with an MMF-3 adapter and remains in current production, usually retailing for about $500.

Olympus’ older, 9- to 18-mm superwide-angle zoom lens is no longer in production, unfortunately. It’s noticeably sharper than its smaller M4/3 replacement. A number of local photographers, myself included, purchased used copies from http://www.lensrentals.com for about $375 plus the cost of an MMF-2 or MMF-3 adapter. We’re all happy with the image quality. However, this is not a weather-resistant lens.

Several Olympus prograde zooms from about 2003 remain available, both used and new. Their very high prices reflect their legendarily good optical quality. These, too, retain full-auto capability and require MMF-2 or MMF-3 adapters.

Just a few days ago, on a whim, I pulled some pre-1974 screw-mount Pentax out of a drawer where they had gathered dust for the past 35 years. Using a $20 Fotodiox M42 screw-mount to Micro Four-Thirds adapter purchased from Amazon, I mounted the Pentax 100-mm f/4 macro and 135-mm f/3.5 telephoto on my current Olympus OM-D. Both lenses were made in the days when compact, well-machined metal bodies were standard, even for basic consumer products.

Because the OM-D has in-body image stabilization and an electronic viewfinder, both lenses were image stabilized, always a concern with a telephoto lens, and provided sharp, clear focusing images in the viewfinder. Setting the camera to aperture-priority mode and the lens aperture ring to the desired setting provided fully automatic and accurate exposure. Manually focusing these lenses requires care, but the results were worth it.

I was dumbfounded and delighted at the extremely sharp images. I probably had very good copies of these lenses. The small CSC sensors use only the sharp central portion of the total image area and that also helps considerably.

Comparable results are possible with Fujifilm and Sony CSC cameras but I don’t have personal experience adapting lenses to these systems.

Older wide-angle and fast normal lenses will probably not produce comparably good results. That’s not a major issue for modern users because there’s a wide variety of excellent current-model optics in wide-angle-to-normal magnifications. Sharp, compact telephoto lenses are the biggest gap in most current optical product lines and that’s precisely where adapting good older lenses makes the most sense.

Not all adapters are created equal, though. Many are poorly made, not mounting the lens squarely. That destroys sharpness. I’ve had the best luck using Fotodiox adapters from Amazon, first ensuring they’re properly aligned and flat, then using Lock-Tite on the set screws to ensure that they stay aligned and flat.

Local attorney Joe Kashi received his bachelor’s and master’s degrees from MIT and his law degree from Georgetown University. Many of his technology and photography articles can be accessed through his website, http://www.kashilaw.com.

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