Lens Tech: Specialty Lenses For DSLR-Shooting Pros
For every job, there’s a perfect tool. Most photography can be handled by your core set of glass, but every once in a while, you need something different. These lenses don’t come out of your bag every day, but when you need one, nothing else will do.
Mirror lenses literally do it with mirrors—they use mirrors to “fold” the light path into a compact package. Most current photographic mirror lenses are actually catadioptric, meaning they contain optical elements along with the mirrors. Mirror lenses also are known as “reflex” lenses.
The primary advantages of mirror lenses are compact size and low cost. The main drawbacks are lower image quality than that of the big-bucks 500mm super-telephotos, and greater fragility.
Mirror lenses generally don’t have adjustable apertures. A 500mm ƒ/8 mirror lens just has an aperture of ƒ/8. Exposure is controlled by adjusting the shutter speed (in manual mode, or letting the camera do it in aperture-priority AE), and by using neutral-density filters. Mirror lenses also turn out-of-focus specular highlights into “doughnut” shapes, which some find interesting and some don’t.
Canon, Minolta, Nikon, Olympus and Pentax once offered mirror lenses (Pentax even had a 400-600mm reflex zoom), but today, Sony is the only SLR maker to offer one. The Sony 500mm ƒ/8 Reflex Telephoto Lens (based on the Minolta optic) costs $749, about one-tenth what you’d have to pay to get a brand-name 500mm super-tele. It’s 4.6 inches long and weighs just 1.5 pounds—compare that with the 15-plus inches and 8.5 pounds typical of a major-brand 500mm super-tele lens.
For non-Sony users, Adorama offers three Pro-Optic mirror lenses in mounts for a variety of popular SLRs. They are the Pro-Optic 500mm ƒ/6.3, the Pro-Optic 500mm ƒ/8 and the Pro-Optic 800mm ƒ/8. Like all mirror lenses but the Sony/Minolta, these are manual-focus only.
Lensbaby offers unique special-effects lenses geared around selective focus. There are three models (Composer, Control Freak and Muse), which allow you to tilt the interchangeable optics to precisely control the focus point and depth of field. The Composer features a ball-and-socket design; just tilt it as desired, and friction keeps it there. The Muse features a short, flexible bellows; you can move it as desired, but have to hold it there yourself while you shoot.
The Control Freak lets you adjust tilt via three screw posts.
Lensbaby Optic Kit
There are nine optics you can attach to the Lensbaby “bodies,” including a single soft-focus optic, a double-glass optic for sharpest results, a plastic optic for really soft effects, a pinhole/zone plate optic, a classic soft-focus optic (produces a soft effect across the entire frame), a fisheye optic (160° angle of view), a macro kit (+4 and +10 close-up lenses), a wide-angle/tele kit (0.6x wide and 1.6x tele-converter lenses) and a 0.42x super-wide-angle optic.