Issue 5: Choosing & Using Lenses

Shallow Depth Of Field
Shallow depth of field is sometimes your friend and sometimes your foe. It depends on the subject matter and what you want out of the picture. Sometimes telephotos are used specifically because the depth of field is so limited it makes the background completely out of focus. This is usually complimentary to the subject, and it forces all of our attention exactly where you want it—on the subject. The blue grosbeak in photo (#9) is an example. The completely blurred foliage behind the bird is a great way to isolate it and make it the center of attention. I did the same thing with the lioness stretching (#10). The background is soft because of the long lens I used.

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To make this point very clear, compare photos (#11 and #12). Both of these images are similar in that I filled the frame with a tack sharp heron and the lighting is attractive. It is true that the direction of light is different—one of them is backlit and the other front lit—but the main difference that makes one of these images successful and the other one annoying to look at is the background. Photo (#11) has a background that is out of focus, but it’s not out of focus enough. It’s too defined because the bird was so close to the leaves that even with a 500mm lens at f/4, I couldn’t blur it as much as I wanted. The background, therefore, is busy and distracting. Photo (#12) is exactly what I wanted. In this case, the heron was much further away from the trees in the background, and the shallow depth of field from the same 500mm lens and the same f/4 aperture made a much cleaner and graphically pleasing picture.

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When the depth of field is so shallow that foreground elements are soft, the photograph usually doesn’t look good. There are always exceptions, but this is a general rule you should keep in mind. For example, in the photo of the chimpanzee baby (#13), I had a problem. I was shooting through an electrified fence into a compound in Kenya established by Jane Goodall. The chimps were just a few feet away and the depth of field was so shallow that I could focus on the eyes of the baby but the mother’s hand was out of focus. I think this is very unattractive and distracting. I had to shoot with the lens wide open (f/2.8) because the light level was low, so that left me with few options. I was using 320 ISO and didn’t want to go much higher, so I solved the problem by shooting two pictures. In the first image I focused on the eyes of the baby, and in the other I focused on the mother’s hand. A couple of weeks later at home I put the two shots together in Photoshop to produce (#14). Both the hand and the baby’s face are now correctly in focus.

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Out of focus foregrounds can, at times, work very well. When you shoot a person or animal through tall grass, it’s like we are getting an intimate look into their private lives. I felt that way when I was able to take a picture of a hunting leopard in the Maasai Mara in Kenya (#15). Note that the foreground grasses are completely out of focus such that they look like a soft green blur. The young Himba girl from Namibia (#16), was also photographed with a telephoto lens specifically to blur both the foreground and background.

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If you are constantly aware of this issue of shallow depth of field and telephoto lenses, you can prevent problems. In the picture of two black tailed deer fawns in British Columbia, Canada (#17), I knew that because of the long lens and the large aperture I was using, the depth of field would be extremely shallow. It might be just a few inches in depth. Therefore, if one of the animals were a foot or two closer to the camera than the other one, the picture would be a failure because only one of the deer would be sharp. Therefore, I waited until both animals were exactly equidistant to the lens before I took the picture. I got lucky in this instance because for one brief moment the two young animals posed for me abreast of each other.

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Rear Mount Filters
Many of the long telephoto lenses that have large maximum lens apertures have front glass elements that are quite large. This means that if you wanted to put a filter on the front of the lens, it would have to be huge and, consequently, it would be very expensive. No one wants to pay hundreds of dollars for a filter, so manufacturers make drop-in filter slots in the rear of these lenses (figure A). This allows you to use a variety of filters at an affordable price.

Figure A

Special Lens Supports
Large telephoto lenses are unwieldy and heavy. They don’t work well on normal tripod ball heads because as soon as you loosen the head to change the angle of the lens, a super telephoto typically flops over and for a moment you think the lens is going to fall off the tripod. In addition, you’ve missed the shot.

Figure B

The specialized tripod head I use to solve this problem is the Wimberly Head (www.tripodhead.com/index.cfm). In (figure B) you can see that it is beautifully engineered, and it balances the lens such that it feels almost weightless. It gives you complete freedom of movement for panning and follow focusing as I did in (#18). It is essential for wildlife, bird, and sports photography, but even if you are shooting people, festivals, an air show, fireworks, landscapes, and many other subjects, you’ll need to use this kind of support. Otherwise, you won’t have the confidence that your normal ball head will be able to support your large lenses to give you sharp pictures. If you regularly use lenses 400mm and longer (or the 300mm f/2.8), you will love the ease with which you can swing the lens into any position and get the shot. Instead of fighting the weight and bulk of the lens, you’ll be able to handle it effortlessly.

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The Wimberly Head replaces the ball head on the tripod. After removing the head, you screw the new piece of equipment onto the tripod screw and the lens fits into it. The controls for movement are convenient and easy to use.

Wimberly also makes the Sidekick. This is smaller, lighter, and less expensive, and it is tightened into your existing ball head but works in a similar fashion.