Tips for Choosing a Telephoto Lens

There are many variables to consider when choosing a telephoto lens(also referred to as a long lens), as well as a variety of lenses from which to choose. One major driving factor in choice of lens is your personal budget. Generally the wider the maximum aperture is the more expensive the lens.

For instance, Minolta(Sony) makes a 600mm f4 telephoto lens for the Maxxum that costs in excess of $6,000. This buger weighs over 12 pounds and the length is slightly under 18 inches. So, weight and size are issues in both the field and during transport.

You may have to opt for a smaller maximum aperture as a tradeoff to control costs. You can find lenses that have different max apertures for a given focal length. If budget is a concern consider checking out one of the manufacturer’s like Tamron, Sigma, or Tokina who make clones of telephoto lenses for specific camera types. Be sure to check lens to camera compatibility.

Teleconverters are optics that can be attached between the camera and lens for increased magnification. They are small by comparison to a telephoto lens and consequently lighter in weight. They come in typical magnifications of 1.4X, 1.7X, and 2X and will increase the magnification of a lens accordingly.

Be apprised that you will loose some light with the use of teleconverters. Some folks call these doublers. The 2X converter actually doubles the focal length of the lens it is placed on. It will also cost you 2 stops of light. For example if the lens you mount the doubler on is a 300 mm f4 then with the doubler in place you will have a 600 mm f8 lens.

Internet search engines have shopping tools which are handy for comparing choices of products side by side. In the case of a lens search you can select specific criteria such as price, manufacturer, focal length, etc. to control the results of your search. You can also check photographic magazines for detailed information uniquely dedicated to lens reviews. On-line photographic magazines will also run occasional reviews that compare different lenses to each other.

Hand-held issues and steadiness will be of greater concern with long lenses than with other lenses due to the nature of the longer focal lengths. The general “rule” of thumb for hand-holding a camera with a lens at a given focal length is that the slowest shutter speed one should use to get a crisp picture is the inverse of the focal length designated as a fraction of a second. For instance if the focal length of your lens is 250 mm then the slowest speed you should select for hand-holding the camera is 1/250 second.

This “rule” is a general guideline. Steadying techniques can be applied to achieve slower shutter speeds. Should you decide to enlarge a print from a hand-held shot that was taken at less than optimum steadiness then to maintain quality the enlargement size may be limited. Any shake will be more noticeable as magnification of the print is increased.

The safest way to reduce the possibility of shake is to use a sturdy tripod. In some lighting conditions with long lenses there are times when you will find it impossible to avoid shake without the use of a tripod. Some telephoto lenses come with their own mounting hardware so they can be attached directly to a tripod for a steadier support.

State of the art hand-holding improvements have been introduced by Canon and Minolta/Sony. Canon created a lens they dubbed as having IS(image stabilization) and Minolta created a camera with what they call anti-shake. Both products will enable one to shoot at slower than normal shutter speeds for a given focal length and still maintain a crisp picture.

When choosing your lens also take into consideration transport and field issues as I mentioned previously. The larger telephoto lenses can especially be a problem. Traveling by air these days with the added restrictions airlines have imposed on passengers carry-on baggage limits have been tightened.

I avoid when at all possible checking any camera gear or lenses to prevent damage, theft, or loss. If you do need to check any camera equipment avoid the use of camera bags or luggage that are marked with recognizable camera equipment manufacturer labels or bags and cases that are easily identifiable as being photography related. For trekking in the field I use a separate carrying case for my large telephoto lens which can be attached to my belt for easier carrying along with my other gear and lenses which are stashed in my camera vest.

I hope these pointers help you choose a telephoto lens which meets your needs in getting the desired photo shot and one that fits your budget.

authored by Lon Britton


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