Bill Silliker, Jr.

The Camera Hunter

The Telephoto Lens: Autofocus Or Not

Sooner or later, anyone interested in serious camera hunting faces the question: what telephoto lens do I need? The answer requires that one first carefully consider three things: photography needs, financial capabilities and physical abilities. 

Answering several other questions first will also help to better understand the unfortunate alliance between "f" stops and where the bucks stop: 

*    What do I want to photograph? 

         *    Do I need top quality images, or can I settle for acceptably sharp results? 

         *     How "fast" a lens do I need? 

         *     How much money will I have to spend?

         *     And, perhaps most important of all for Maine camera hunters who often have to backpack their gear to get to the real action, how heavy is the doggoned thing?  

Telephoto Tutorial

The longer a telephoto lens, the more firepower it has. Think in terms of 50 millimeters at a time; 50mm is 1X power, 200mm is 4X power, 500mm is 10X power and so on. 

To photograph people hiking, canoeing or in other outdoor pursuits, consider getting a short telephoto lens, something in the 200mm range. Modern zoom lenses with variable focal lengths in the 80-200mm range make a good choice for that type of shooting.

A 400mm to 500 mm range telephoto is better for most wildlife photography. And if it's wildlife you want to photograph, you need to consider that most wildlife in Maine comes out to pose in the early morning and late afternoon. A telephoto lens that allows lots of light to reach the film permits you to shoot in such lower light conditions. 

You can compensate by using a fast film, say ISO 200. If your aim is to shoot prints for the wall made from color negative film, you’ll do just fine, even with up to ISO 400 speed film. 

But if your ambition is to sell pictures to magazines,  you'd better think about it. Slide films are the only choice for most professional wildlife photographers. That's because most publishers demand slide film of speeds no higher than 100 ISO. 

Lenses that gather lots of light are called "fast" because you can use a faster shutter speed. The lowest f stop number - f2.8, f4, f5.6 -  that a lens opens up to describes its speed. An f2.8 lens is a very fast telephoto lens, an f4 lens is moderately fast and an f5.6 lens is a slow lens. Anything slower is a dog.   

 Faster shutter speeds not only stop the motion of wildlife, but they also help to produce sharper images since they offset vibrations made by the camera. 

The more light that a lens gathers, the more glass it requires to do so. The more glass, the more mass. The more mass, the more cash. And if you want your fast telephoto lens to be an autofocus version to go with that fancy new camera body you ran out to buy after reading the last Camera Hunter column, think MEGACASH.

Lens Costs

My first professional telephoto, a Nikkor 400mm f3.5 manual focus lens, sold for over $3000 at the time. That lens is only one/half of a stop slower than the f2.8 400mm lens that sold for nearly $2000 more! You need either an understanding spouse or a divorce to be able to buy such a lens.

You also need more energy to get it into the woods. Consider that the Nikkor 400mm f3.5 manual focus weighs over 6 pounds. The tripod and head needed to support such a lens for sharp pictures runs about 10 pounds. That's 16 pounds before you even stick a camera body on it. It's fun lugging all that up a hill the likes of Katahdin. But the effort it cost worked for me: it produced very sharp images that made photographs worth money. 

Today I use a 500mm f4 Nikkor lens. I use the autofocus version, since I employ AF a good deal of the time, what with the capability of Nikon’s latest autofocus cameras. That lens cost over $7000. And it weighs even more than the 400mm lens did! 

But my take of publishable wildlife images soared to over 20 per roll. I used to be happy to keep even 10 wildlife photos from a 36 exposure roll of film. So the cost of that autofocus lens has been offset as my file of salable images grows. And I still climb an occasional hill with it! One can do well with less expensive, slower camera brand telephoto lenses on the market - the Minoltas, Nikons, Canons and such, that have apertures in the 5.6 range. You can also do quite well with several of the non-camera brand manufactured lenses that are even less costly. Sigma, Tamron, Tokina and Vivatar make some decent quality slower speed autofocus 400mm lenses, even some that start at around $500. 

Why not buy a shorter lens and stick a teleconverter, or a so-called doubler  on it? A teleconverter does increases the reach of a telephoto lens, but you won't be happy with the results of a cheap teleconverter. If you must use a teleconverter, it’s best to stick with the teleconverter designed by the manufacturer of your lens. Good teleconverters cost at least several hundred dollars, often as much as $500. 

All teleconverters soften your images a bit. While the more expensive ones make acceptably sharp images, a teleconverter also steals at least a stop of light, making a lens even slower. 

More Help

Just remember that you get what you pay for. There are always trade-offs. Check the photo magazines for critiques of any lens before you buy. Some libraries keep back issues of Popular Photography or Outdoor Photographer magazines, two good sources for lens reviews. Catch yours in the good light.

Bill Silliker, Jr. teaches wildlife & nature photography for L.L. Bean's Outdoor Discovery Schools and has done the photography for 5 books, several of which he also wrote. He is editor of the website www.wildlifewatcher.com as well as for his own website at www.camerahunter.com

© Copyright 2000 Bill Silliker, Jr. all rights reserved.