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The Poor Man’s Super-Telephoto

Using a tele-extender can give your long lenses even more punch for wildlife and landscape photos

This Article Features Photo Zoom

Canon Extender EF 2x II

The lens of choice among the serious pro wildlife photographers I know seems to be the 600mm ƒ/4 super-telephoto. It’s great for subjects that won’t let you get close, is incredibly sharp, and autofocuses quickly and accurately. However, it costs over $7,000. That being just a bit beyond my budget, when I really need “reach,” I turn my $1,200 300mm ƒ/4 lens into a 600mm ƒ/8 by attaching a $300 2x teleconverter between the lens and camera body.

Also known as tele-extenders, teleconverters are available from the major lens manufacturers for their long lenses, and offer three major benefits.

First, as just cited, they’re an economical way to get superlong focal lengths. And they’re not just for the budget-challenged. Pros use them, too—a 1.4x converter turns that monster 600mm into an 840mm; a 2x converter, into a 1200mm.

The second benefit of the teleconverter is that it doesn’t change the lens’ minimum focusing distance. Add a 2x converter to a 300mm lens that focuses down to five feet, and you have a 600mm lens that focuses down to five feet. (For comparison, my camera manufacturer’s 600mm super-telephoto won’t focus closer than 18 feet unless you attach it to an extension tube; but then it won’t focus out to infinity.)

Sigma APO Teleconverter 1.4x EX

The third teleconverter benefit is lack of bulk. A 300mm lens with a 2x teleconverter is much more compact than a 600mm ƒ/4 super-telephoto lens. (A 600mm ƒ/8 prime lens also would be smaller than the 600mm ƒ/4, but currently no one makes a 600mm ƒ/8.)

Of course, teleconverters do have some drawbacks, the biggest being that they reduce the amount of light transmitted to the film or image sensor—by 1 stop for a 1.4x converter, 1.5 stops for a 1.7x converter, and 2 stops for a 2x. Add a 1.4x converter to a 300mm ƒ/4 lens, and it becomes a 420mm ƒ/5.6. Add a 2x converter to the 300mm ƒ/4, and it becomes a 600mm ƒ/8. TTL metering automatically compensates for the light loss, but the necessarily slower shutter speed reduces action-stopping power.

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