Long telephotos

When focal lengths extend beyond ten times that of a normal lens, long telephoto lenses are indeed the result. These exceptional lenses start at about 10 power (500mm) and range all the way to perhaps 24 power (1200mm). Beyond that telescope adaptations take over. Lenses at the shorter end (mostly 500 mirror optics) are reasonably plentiful but as focal lengths expand, numbers dwindle.

Lenses of this huge power have special problems and need special handling. Weight and bulk increase along with focal length, but maximum apertures move in the opposite direction, getting smaller as lenses get bigger. Smaller apertures dictate slower shutter speeds at the very time when theses clumsy lenses need the very fastest speed to reduce the camera shake. The only way to minimize shake and use slow speeds as well is to put the lens on a sturdy tripod every time. And it is the lens that goes on the tripod, not the camera. At these focal lengths the lens is so much larger than the camera, that it is the camera which becomes an attachment to the lens, not the other way round.
 

Even with a tripod steadiness is not always assured. Magnification is so enormous with a long telephoto lens that the slightest movement of the camera or lens causes the image to dance wildly. Some photographers have devised alternatives to the ordinary tripod. A pentapod (five-legged “tripod”) has been used, as have been beanbags, weighted straps over the lens and other such devices. In any case be sure to trip the shutter with a cable release. A finger applied directly to the shutter release on the camera body could set up the kind of vibration you are trying to avoid.
 

Mounting camera and lens firmly on a tripod has more benefits than just minimizing vibration. It also takes the weight of a heavy lens off your arms and allows you to line up and frame a highly magnified image with more precision. Also, since long focal lengths tremendously reduce depth of field, a tripod makes possible slow shutter speeds which, in turn, permit smaller stops and greater depth.
 

To what subjects is all this power applied? In many instances, it is applied to the same subjects suitable for a medium telephoto lens. Only now the camera to subject distances is greater. You might be able to shoot a sporting event from a seat down near the players, but a professional photographer may be confined to a press booth high up in the stands and he or she may have to get tight close ups of action on the field from there. A long telephoto lens will be needed to span the increased distance. A photographer in the wilderness may need a very long lens to get any picture at all of a timid and alert animal that stays a considerable distance away.

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More about telephotos lenses

- Short Telephotos Lens
- Medium Telephotos Lens
- Mirror Lenses and Telescopes
- Tele Extender
- Characteristics of Tele Lenses
- Tips on how to handle long lenses