Lens Adapters

Lenses are specifically designed for each format of camera. They involve many factors such as: format, resolution, coverage, cost, demand, and sales hype.

Lens adapters are usually a compromise. If they are a modification to fit a camera with the same format only automatic features may be compromised, if a lens is designed for a larger format (image area on film or chip), only a smaller part of the image is used.

There are very few adaptation to use lenses designed for a smaller format on a larger format camera. Lenses cover a larger area when they are extended out of their mount by a bellows or extension tubes for close-up work. Slower lenses and simpler designs generally work best, though some 35 mm still retrofocus lenses work very well in their reversed position for macro work. Any 35 mm SLR lens wider than 35 mm is probably a retro focus lens. Most longer focal length telephoto lenses don't do very well extended.

A 8 mm or Super 8 movie lens will cover a 35 still or movie format if extended far enough our of the mount. But, because of the extreme extension the lens becomes very slow.

Putting 35 mm still lenses on say a Canon XL 1 is not very smart for various reasons. 1. The lens is designed for a much larger format (1" x 1-1/2") and only the center 1/3" is being used. 2. Focal length alone determines image size. The Canon already has a zoom designed for that format that is max. a 88 mm lens. Putting a 85 mm still lens will give the same image size and little is gained. So to get more telephoto than the standard zoom, you would need a heavy lens designed for a much larger format. The adapter sold by Canon can be useful for macro work, but the use of diopters is usually more user friendly.

The XL 1 is a good camera, but shares with its competitors the rubber band electronic focus feel that all low end cameras have today. You have to spend a lot more money to get a real mechanical zoom and focus lens. On the plus side, the auto focus on most cameras today is supurb and can be relied on even if the LCD viewfinder resolution is much less than the chip is recording.

There are some adaptation. Older Nikon F lenses will adapt to Canon breach lock cameras. The adapter is weak, but will work well with care. Of course no auto features are usable. There are not other 35 mm adaptions that I know of that will focus to infinity. There are many cross camera adapters, but they will not focus to infinity because the lens end up farther from the film that the manufacturer's lenses. They are extended. For close-up work it can save buying more lenses if you have different cameras.

For cameras that have non interchangable lenses you con only use diopters, wide angle and telephoto attachments, some of which are very good. Some can be adapted with a step-up or step-down ring. With wide angle adapters on consumer camcorders you will not be able to see focus. Trust the autofocus. You can focus and turn off the focus in situations where the subject is not centered where the autofocus system gets it's distance information.

Most video lens produce poor images on 16 mm even if the lens covers the frame. The same is true for many 16 mm film lenses on video camera with a C- mount. There are a few adapters that will allow still lenses to be used on the Betacam, Sony Standard bayonet mount. They work in the macro mode and will not focus to infinity. Some 2-1/4 square still lenses would work but that is really wasting image coverage.




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