Sunday, August 23, 2009

Nikon News Hound : Nikon Manual Focus Nikkor Reflex Lenses

Left to right: Tamron 500mm f8, 500mm reflex Nikkor-c ƒ8, 500mm reflex Nikkor ƒ8, Nikon 500mm Ais-P ƒ4 with lens hood, Nikon TC-301 2x teleconverter, Nikon 500mm Ais-P ƒ4 no lens hood, 1000mm reflex nikkor ƒ11

Q: Hey Dad — what's a reflex lens?

A: One that folds the light by way of mirrors.

While to some it still may seem that reflex lenses are your Daddy's glass — or even Grandpa's — nothing could be further from the truth. Nikons high quality super-telephoto reflex lenses are just as engaging and useful — or more so — today as a few decades ago. Almost every Nikon mirror lens — excepting a few older models — can be popped in and twisted onto your favorite professional Nikon SLR digital camera. The scope, reach, and resolve of these Nikkor reflex lenses return high quality results when used correctly.

Reflex lenses are commonly referred to as catadioptric lenses — CAT lenses (for short), or mirror lenses. These terms are used interchangeably — however more people are accustomed to searching with the term "mirror lens" than any of it's synonyms. Compared to refractive glass lenses, mirror lenses are shorter, lighter, and more cost effective. Some non Nikkor reflex lenses first appeared very early on for rangefinder cameras, but by far the most popular mirror lenses were designed for use with SLRs. Their compact design, narrow field of view, and relatively low cost — when compared to refractive alternatives — started a trend that almost every SLR camera maker added to their lens lineup.

This availability also brought mirror lenses into reach of consumers who weren't familiar with their limitations or how to best manage them. At a time where ISO film ratings were generally much lower than the equivalent ISO available to today's digital sensors, yesterdays photographers were challenged to compensate. Here are the primary things to check when using mirror lenses:

  1. Pre-visualize your subject and your out of focus highlights. Use them to your advantage.
  2. Be weary of the light scatter, and thermal activity in front of your subject.
  3. Use a high quality mirror lens — like any of the nikon manual focus nikkor reflex lenses.
  4. Use a viewfinder magnifier for critical focus.
  5. Use enough shutter speed — freeze your subjects despite the limited fixed aperture of this lens.
  6. Use the most sturdy tripod and head that you own. After all, these are super telephotos.
  7. Engage the mirror-lock if you are gifted with that opportunity and use a remote release.
  8. Practice sound long lens technique.
  9. Make sure the optical filter in the rear is correctly positioned. It's part of the optical pathway.

Mirror lenses are no more difficult to use than refractive glass lenses providing the photographer learns to pre-visualize with them. Treat them with the same respect as any super telephoto lens. Nikon made several models : a 500mm ƒ8, a 1000mm ƒ11, and the 2000mm ƒ11 behemoth weighing 17.5kg (38.5 Lbs). The first two are easily used in the field, whereas the last one requires a special yoke and support — restricting it to stationary use. The early 500mm Nikkor C reflex was exceptionally sharp at infinity. The more recent close focusing version — circa 1983 — is better at shooting objects 3–10 meters (6–35 feet) away. The late model 1000mm is even sharper at infinity which carries over when used with a Nikon TC-301 2x multiplier. The 2000mm is the most difficult lens to get a hold of with less than 1000 specimens made — but offers 40x magnification over a regular lens at ƒ 11.

Aside from one model currently offered by Sony, todays camera makers no longer host a proprietary mirror lens in their lens lineup. It's unfortunate that the inability to use these lenses correctly caused them to fall out of favor with consumers. Mirror lenses are currently the best optics available for telescopes, and there is no reason a well designed and built mirror lens — when used correctly — can't meet or exceed the quality of refractive competitors available today. This void presents a real opportunity for camera makers to correct. Until then, most Nikon manual focus Nikkor reflex lenses — available second hand — can be adapted for use on your professional Nikon SLR digital camera today. Shoot in raw picture mode to recover the maximum amount of dynamic range. As with all Nikkor reflex lenses,

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