Extend Your Telephoto Range with a Converter

If there's one thing (optically speaking) that DSLR photographers always want more of it's a longer telephoto range. Even with the long telephoto lenses available (300mm is common with zoom lenses) and the fact that these lenses are even more powerful on a camera with a cropping factor, there's always a desire to have longer and longer lenses. And for certain types of photography like wildlife and sports, big telephoto lenses are a huge help, no question. It's nice to be able to fill the frame with a songbird across the yard, or a third-baseman across the field.

The problem is that once you get past the 300mm range in a zoom or straight telephoto lens, you're getting into some very expensive pieces of glass. A good quality 600mm lens can set you back around ten grand--yikes! I'd rather put a down payment on a condo in Florida than spend that kind of money on a lens. But there is a relatively inexpensive alternative: telephoto converters. A converter is a tube with glass elements that fits between your existing lens and magnifies the telephoto range of the lens. Typically these converters come in either a 1.4x or 2.0 power (and magnify the focal length accordingly); so with a 300mm lens and a 1.4x converter, you have, in effect, a 420mm lens. No we're rocking! But now add in the 1.5x copping factor that is common on many DSLR camera bodies and you're looking at (or through) a 630mm lens! Fantastic.

The great thing about converters, as I said, is that they only cost a fraction of the price of an equivalent lens. I shot the second of the two photos above with a Kenko Teleplus Pro 2.0 converter on a Nikkor 70-300mm f/5.6 lens set at 230mm (in 35mm terms)--the equivalent of a 460mm lens. How cool to be able to double the focal-length of the lens I was using by slipping a converter onto the camera--it takes literally just a few seconds to do. B&H sells the Kenko converter for around $220.

Are there any drawbacks to converters? Yes. One is that there is some potential degradation of sharpness and the degree really depends on the quality of the converter. To be honest I didn't notice any measurable loss in sharpness with the Kenko--in fact, I found it to be supremely sharp if you lock the camera down on a good tripod. (The photos here are sharper than they look online, by the way, the online compression strongly affects sharpness--never judge the quality of an image by its online reproduction.) There is no way to get a sharp photo with a 460mm lens without a tripod--not going to happen. Some photographers complain about a lack of sharpness with converters but neglect to mention they're trying to handhold enormous lenses. Also, any time you use a longer lens you're going to lose depth of field (it's just an optical fact) and I think some photographers see that lack of DOF as a lack of sharpness--they're not the same thing.

Keep in mind though, the longer the lens you're starting with and the more converter power you add, the more likely you are to see some loss of sharpness. Is the loss a deal breaker? No way. You can more than make up for any softness in editing, again, provided you used a good tripod and a fairly fast shutter speed. If it comes down to not getting the shot or getting shot and having to sharpen it later, I prefer to get the shot.

There is a loss of about a stop of light with all 1.4x teleconverters (about two stops with a 2.0 converter) and that's just part of the price you pay to get a longer lens. It's simple to overcome the loss of a stop if you need it by just doubling the ISO--from 200 to 400 for example--and that buys you back the lost stop. You might notice some slowness of focus with any teleconverter and I do notice that at times, but if you find a good edge to focus on, it's not much of an issue.

Finally, one of the best things about a teleconverter is that it will fit in your jeans pocket. If you're out hiking and you are carrying a 70-210mm or 80-300mm lens, you can double that range with something that fits in your pocket. Yes, you might lose a bit of sharpness and you will lose some light, but when you compare the weight, cost and convenience factors, it's hard to ignore the beauty of a good-quality converter.

Telephoto Lenses: Beware Compressed Background Clutter

The ability to cut through space and make distant subjects seem much closer is the reason most people want long-focal-length lenses and it's also why camera manufacturers work so hard at making good-quality and affordable zoom lenses. Long telephoto and zoom lenses are great for sports, wildlife or candid people photography or any situation where you want close shots of far-off subjects close. In a lot of situations (like sports) using a long lens is the only option you have.

One of the problems of using longer focal lengths though is that they compress the apparent distance between different areas of your compositions. While this can be a creative advantage at times (compressing a silhouette of a sailboat into a setting sun, for example), it can also create situations where it's hard to separate the main subject from the background--as is the case in the top photo. I shot this photo of a tugboat in New York harbor (from the New Jersey side of the Hudson River) using a Nikkor 70-300mm lens at 165mm (which is roughly 247mm in 35mm terms). While I like the idea of the Manhattan skyline behind the tug, from the vantage point that I had there is no separation between the boat and the buildings. Had I been able to find a better vantage point (perhaps a more head-on angle on the tug), the focal length might have been fine. But as it is, the background seems to clutter the shot too much.

As the boat came closer to me though, I zoomed out a bit to a focal length of 220mm (about 330 in 35mm terms) and waited until it cleared the clutter of the buildings and had just an open river (and in the distance the George Washington bridge) behind it. If I had had the time, I would have backed off on the zoom a bit and shot the entire boat, but because it was moving so fast and I wanted a closer shot, I had to shoot very quickly. By the time I got this shot the boat was almost right in front of me. And as I said, I really wanted a shot of the tug in front of the city buildings, but when you're shooting moving subjects you don't always get what you want.

Whenever you're using long telephoto lenses (anything that is longer than, say, 135mm in 35mm terms) be aware of what is behind your subject and make sure the compression isn't combining the near and far in an unattractive way. If it is, see if you can find a better angle so you can see some space between near and far and if not, you might have to alter your composition a bit or back off on the zoom. In this case I was lucky because the subject was moving and I was still able to use the longer focal length but choose an alternative background.

Compress Space with Telephoto Lenses

One of the interesting qualities that telephoto lenses have is that they compress space--and the longer the focal length is, the more the compressed space appears. We've all seen shots of a football player who is catching a pass and appears to be almost in the stands with the crowd. The reason they appear so close together is because the photographer used a very long lens and the space between the player and the spectators just evaporated.

In landscape photography compressing space can be a fun tool because it brings together distant elements in a very believable way. I photographed the sunset here outside of Tucson, Arizona using a 300mm lens (equivalent of 450mm on my Nikon D70s body because of the 1.5x cropping factor) and it appears that the saguaro cacti and the mountain range are relatively close. In reality the brushy hillside and the saguaro are about 100' from me but the mountain is probably 20 miles away (and the sun is millions of miles away!). But by using the power of the telephoto lens to shrink spaces, the three layers of the photo (hillside/mountains/sun) all appear incredibly compressed.

Next time you're out shooting landscapes, shoot a few frames of a scene with a normal lens and then either zoom in (using a built-in zoom lens) or, if you have a DSLR, switch to a long telephoto and compare the resulting images. It's great fun to see space compressed like this and the illusion is very convincing.

So if telephoto lenses compress space, what do wide-angle lenses do? Next time.