Telephoto lenses

Telephoto lenses are perhaps Canon’s most distinctive products, easily recognized wherever they are used. Whether it’s a group of photographers at the Olympic Games or on the sidelines of the Super Bowl, photojournalists at a presidential press conference, or camouflaged war photographers in a battle zone, the long, white barrels are ever prevalent and always noticeable in every important and prominent event involving photography.

A telephoto lens is not always a zoom lens, although the terms are frequently used interchangeably. A telephoto lens can be a prime, or fixed, device, or it can be a zoom that ranges between minimum and maximum focal lengths. Telephotos, however, always magnify distance to make it seem closer than it is; furthermore, the longer the distance they magnify, the more compressed the images appear. They are excellent at creating narrow depth-of-field shots from far away, as in 6-20. The amount of telephoto magnification you need depends on how close you can get to your subject. If you’re shooting at the sidelines of a football game, for example, you’ll need a lens that’s at least 300mm or more; pro field sports (for example, football and soccer) and wildlife photographers often use super-telephoto lenses of 400mm or higher because it is more difficult to get close to their subjects. On the other hand, if you’re using a telephoto lens at a wedding, you probably won’t need it to be longer than 200mm.

Taken at the Great Pyramids in Egypt with a telephoto zoom lens while at least 30 or more yards away 1D Mark lln, EF 70-200mm f/2.8L lens, ISO 100, 1/640 second at f/9.

Many telephoto lenses integrate Canon’s innovative IS, or Image Stabilizer, technology to ensure sharper images. The longer the lens, the more shaky it can be, even at shutter speeds where you could easily and stably hold a normal or wide-angle lens — such as 1/125 or 1/250 second. If you’ve ever watched a space shuttle launch on TV, where they use very long super-telephoto lenses with video cameras, you’ve undoubtedly seen the shakiness even when those cameras and lenses are being tilted smoothly on a tripod. Your telephoto lens benefits from the IS feature, especially with longer exposure times. With the IS turned on, you can put your ear against the lens and depress the shutter release to the metering point and actually hear the motor whirring. This is a proprietary Canon gyroscopic technology using two vibration gyros to take measurements and a microcomputer to actually shift optical elements in the lens at an inverse ratio to the lens movement. This keeps the position of incoming light stable, preventing blur.

Some of the Canon telephoto lenses, such as the EF 70-200mm f/2.8L IS USM, also include a switch that lets you limit the focal range at the minimum focusing distance. For example, it lets you set the minimum distance from 1.3 meters to 3 meters; this actually speeds the lens’s time to autofocus given it doesn’t have to gauge as much of the lower range. Natural-looking shots are possible with telephoto lenses, as well, as long as there is not too much depth in the image (which compresses it). It’s very possible to take natural, normal-type shots with a telephoto lens with the right exposure and settings, such as in figure 6-21.

Often I cannot get close enough to subjects at medal ceremonies, so I must use a telephoto zoom, such as this photo of medalists at the 2006 World Fencing Championships in Torino, Italy Taken with a 1D Mark IIn, EF 70-200mm f/2.8L lens, 550EX flash, ISO 320, 1/160 second at f/4.

There are numerous choices you need to make, and questions you want to ask yourself, when choosing a telephoto lens:

  • How far away are the subjects I need to shoot?
  • Can I use a shorter telephoto lens for most of my work, and occasionally use a lens “extender” to get more focal range if I need it, and to save money?
  • Will I need to zoom in and out of subjects quickly, or can I use a prime lens?
  • Will images I take be in low light, or can I use a slightly slower telephoto lens?
  • How important is the Image Stabilizer technology for my work?
  • What is the range compared with my other lenses — is there an overlap or not?

SEE ALSO:


NOTE

Softfocus is a two-setting lens feature that provides soft-focused shots that, while soft-looking, are not blurry. The lens also takes sharp, nonsoft photos as well.


NOTE

DO in the lens designation stands for diffractive optics, which makes a lens very compact for having such a long focal range. This is accomplished using Canon optical technology to reduce size and increase image quality. If size is a primary issue for you, this lens is an interesting option.

Category: Science of Lenses

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