S3Support: Scientific, Social, and Spiritual Support

Normal Lens | Zoom Lens | Wide Angle Lens | Telephoto Lens

Normal Lens

A normal lens is also a good choice for informal photos of people. It provides sharp pictures, sufficient depth of field, and little distortion. For more formal portraits, use a moderate telephoto lens.

The normal lens is the one that comes with most 35 mm SLR cameras. Because it gives such natural-looking pictures, you'll probably use it more than any other lens. The normal lens receives its name because it provides a natural perspective and an angle of view similar to the central vision of the eye.

The focal length of the normal lens for most 35 mm cameras falls between 45 to 55 mm.

The focal length of a camera lens is the distance from the film plane of the camera to the center of the lens when the lens is focused on infinity.

The normal lenses on 35 mm cameras are usually fast, having maximum apertures of f/2.8, f/2, or as large as f/1.2. With today's fast films, a normal lens with a maximum aperture of about f/1.8 will usually suffice. You will pay much more to get a lens with a maximum aperture of f/1.4 or f/1.2. A lens with a large maximum aperture lets you handhold the camera to take pictures in dim light. Using a large aperture, such as f/1.8, also enables you to use high shutter speeds to stop action. However, the depth of field is quite shallow at such maximum apertures. Focus carefully. Otherwise you risk out-of-focus blur with all but distant subjects.

Zoom Lens

If you're on the brink of Niagara Falls, you won't be able to move closer to get a larger image. Whenever changing viewpoint isn't practical, a zoom lens will prove vital. A 28 to 200 mm zoom lens was used for this series.

Certainly the most popular lenses in use today are zoom lenses. Though early zooms suffered from the reputation of being heavy, awkward to use, and less sharp than fixed-focal-length lenses, today's zoom lenses are compact, easy to use, and sharp. Zoom lenses are available for both manual-focus and auto-focus cameras.

Zoom lenses offer you the flexibility of many different focal lengths along with the convenience of having to carry only one lens. For example, instead of carrying a wide-angle, a normal, and a telephoto lens, you could take along a single zoom lens with a range of 35 to 135 mm. Such a zoom not only replaces several fixed-focal-length lenses, but also offers you all the focal lengths that fall within that particular zoom range. Instead of having to decide between a normal and a telephoto lens, for instance, you could use a focal length anywhere between the two.

The convenience and versatility of zoom lenses has made them popular with photographers. This 28 to 200 mm zoom lens could replace all the single-focal length lenses behind it.

Equally enticing is that a zoom lens lets you fine-tune your compositions without having to change your shooting position. Instead of walking closer to or farther from your subject, you can remain in place and adjust the focal length to fit the composition you have in mind. With a wide-angle-to-telephoto zoom, for instance, you could take a group shot around the picnic table at a wide-angle setting and then zoom in close to take a full-frame portrait without taking a step.

Zoom lenses are available in a variety of focal-length ranges. Among the most common are those that cover a wide-angle-to-normal range (28 to 50 mm or 21 to 50 mm), a wide-angle-to-medium telephoto range (35 to 105 mm or 35 to 135 mm), and a medium-telephoto-full- telephoto range (80 to 200 mm). The zoom lenses with the greatest ranges - 28 to 210 mm and 50 to 300 mm, for example - tend to be heavier and less sharp than those with more moderate ranges. They're also more expensive. Their close-focusing distances may be as far as 10 feet.

If you are thinking of buying your first zoom, those in the wide-angle-to-medium-telephoto group (35 to 135 mm, for example) make a good choice; they offer a great range of focal lengths in a lightweight package and have relatively fast maximum apertures. Also very useful are the medium-to-long-telephoto zooms (around 70 to 210 mm). They provide you with substantial telephoto capability, but still allow you to broaden the composition when necessary. Many zooms in this range also have macro capability, which lets you take close-ups of small objects.

Most zooms in use today are called "one touch" lenses. You focus the lens and change focal lengths by pushing or pulling on the focusing collar. A few zoom lenses are "two touch;" they have separate controls for focusing and zooming. Auto-focus zooms are available too, and they're even easier to use; they do the focusing and leave you to concentrate on adjusting the focal length.

What are the disadvantages of zooms? Weight is one disadvantage (especially among longer telephoto zooms); zooms are heavier and bigger lenses. Flare is another; especially in backlit situations, zoom lenses may flare noticeably, scattering light throughout the picture. But when you compare carrying one zoom lens to carrying several fixed-focal-length lenses, the zoom ends up being the lighter choice. Zooms also cost a bit more than fixed-focal-length lens of similar focal lengths, but again, one zoom is cheaper than several fixed-focus lenses and considerably more flexible.

A more serious drawback of zoom lenses is that they are generally slower, i.e., they have smaller maximum apertures, than equivalent fixed-focal-length lenses. Also, most zooms have a variable maximum aperture that gets smaller (letting in less light) as you move toward the longer focal lengths of the lens. A 70 to 210 mm f/4.5-5.6 lens has a maximum aperture of f/4.5 at 70 mm, for example, but a maximum aperture of only f/5.6 at its longer focal lengths. The smaller aperture means slower shutter speeds, which can increase the likelihood of blur from camera shake or from moving subjects. Because it lets in less light, a smaller aperture makes focusing more difficult, too, particularly in low light levels.

Finally, remember that all of the information we're about to discuss for wide-angle and telephoto lenses also applies to zoom lenses that have wide-angle or telephoto focal lengths.

Wide Angle Lens

With a wide-angle lens, you can more easily include foreground subjects and emphasize the distance to the background. Here the photographer used a wide angle with a small aperture to make both the foreground and background sharp.

A wide-angle lens has a shorter focal length than the normal lens for the camera. A wide-angle lens takes in a greater angle of view than the normal lens. From any given spot a picture made with a wide-angle lens includes more than a picture made with the normal lens.

When do you use a wide-angle lens? Some of its uses are rather obvious. A wide-angle lens is helpful for taking pictures in places where space is limited. Without enough space, you just can't move back far enough to include everything you want with the normal lens. When you're photographing such subjects as all the in-laws around the Christmas tree at home or a brand-new sports car on display at a crowded auto show, a wide-angle lens is a very handy item to have.

A wide-angle lens is often a good friend to have outdoors, too. When you take pictures in narrow city streets or crowded public markets or photograph sweeping scenic vistas, a wide-angle lens will let you get it all in when this isn't possible with the normal lens.

Another situation where a wide-angle lens may help you is in public places when people or other objects are between you and your subject. You may be able to eliminate them from the picture by using a wide-angle lens which allows you to move closer to your subject and frame the picture the way you want it.

Telephoto Lens

A telephoto lens is required for wildlife photography. In this image, the photographer created a frame around the Bald Eagle by using a large aperture, throwing the tree leaves out of focus.

A telephoto lens has a longer focal length than the normal camera lens. Technically, the term telephoto refers to a particular kind of optical arrangement that has a positive front element and a negative rear element. This allows the physical length of some telephoto lenses to be shorter than the focal length. However, it has become common practice to call any lens with a focal length that is longer than normal a telephoto lens, so that's what we do.

Telephoto lenses do just the opposite of what wide-angle lenses do. They include a narrower angle of view than the normal lens, so they take in a smaller area of the scene. Consequently distant subjects photographed through a telephoto lens appear closer than they do when photographed through a normal lens. A telephoto lens magnifies the image similarly to the view you see through binoculars or a telescope.

When do you use a telephoto lens? As a rule, you use a telephoto lens when you can't get as close to your subject as you'd like-for example, when you're photographing a baseball game, an alligator in Okefenokee Swamp, or a chalet perched on a distant hillside. You can't climb into a cage at the zoo to get a close-up of a lion or stand in the middle of the Hudson River to get a close-up of a luxury yacht, but a telephoto lens can produce a big image of such subjects by bringing them closer to you optically.

Information as published by Kodak.

For further information contact: information@brandaport.com
Phone: 954-974-5818 Fax: 954-974-5720