Photo Tip – Camera Lenses
Written by Mike Cheliak on July 13, 2009 – 9:56 am -WHAT YOU SEE IS WHAT YOU GET…
Much of your success in your photography pursuits will depend on the quality of the lens you have. The optical quality of the lens whether on a point and shoot fixed lens camera or on a DSLR will give you results 
that vary greatly. What your sensor sees is truly what it gets.
Most consumer digital cameras are sold with a fixed zoom lens that can’t be removed or replaced. One big advantage is that the camera is sealed so no dust can get on the image sensor. Digital SLR cameras have removable lenses so you can change them when circumstances dictate. While most of your initial budget with a DSLR will be on the camera; it is always a good idea to really research your lens needs in advance and provide a higher price budget to get a better quality lens. Your lens will be with your through your first, second, third and fourth camera and beyond if you take care of it.
Commando Fact
Although it may sound like a SCI-FI movie, there are a number of liquid lenses now being used in some camera phones! They focus by changing shape when controlled by electrical impulse controls.
THE EYES OF THE BEHOLDER…
Many lenses display information that is useful in your photography. Be sure to consider this information when choosing a lens and take the time to read any printed information that comes with a lens. You camera lens is truly what gives you the photos you are looking at. Your photos are only as good as the lens that sees them.
FOCAL LENGTH
The focal length of a lens has a huge impact on your images and is one of the most important tools in your creative tool box. On fixed lens cameras you change the focal length by using your zoom lens. On DSLR’s you can do the same or change lenses. T he various focal lengths you can use are referred to by terms that can be confusing at first.
- Wide-angle, short focal length, short lens and zoom out refer to the same thing lenses that capture a wide expanse of a scene.
- Telephoto, long focal length, long lens and zoom in refer to the same thing lenses that bring distant subjects closer.
The focal length you choose is a creative choice because it has two effects on your images:
Angle of view refers to how much of a scene the lens covers. Fisheye lenses, the widest available, can capture up to 180-degrees. As you zoom in or change lenses to increase the focal length, the field of view narrows and you can isolate small portions of the scene without moving closer to the subject.
Magnification is related to the lens’ angle of view. Since using a short focal length lens or zooming out includes a wide sweep of the scene, all of the objects in the scene are reduced to fit into the image. Zooming in or using a longer focal length lens gives a much narrower angle of view, so objects in a scene appear larger.
Your choice of lens depends in part on what you plan to do with the camera. Wide-angle lenses are best for photographing buildings, landscapes, interiors, and street photography. Telephoto lenses are best for portraits and many nature scenes. Normal lenses are a compromise.
ZOOM…ZOOM
Most fixed lens cameras have a built-in zoom lens. Zooms are also the popular choice with most DSLR users. These lenses are popular because they let you choose any focal length within the range the lens is designed for. A zoom lens for a DSLR’s can range greatly in price based on a number of factors. Optics quality, features such as IS (image stabilization) or VR (Vibration Reduction), the range of the zoom, a floating or fixed f/stop and more can bring your lens anywhere from a couple hundred to several thousand dollars. You have to take into consideration where the lens will be used, what you are willing to budget and truly ask yourself, “Do I need this feature?”
IT’S THE NORM…
A “normal lens” for a 35mm camera usually refers to a fixed focal length lens of 50mm or a zoom lens zoomed in a little from its widest angle. When using a lens of this focal length, the scene looks about the same as it does to the unaided eye. With a longer focal length, everything appears closer than it actually is. With a shorter focal length, everything looks farther away.
THE SHORT OF IT…
Using a short focal length lens or zooming out gives you a wide-angle of view that lets you capture a wide expanse of a scene. This view is ideal for use in tight spaces, such as when photographing landscapes and in small rooms where you can’t position the camera a great distance from the subject.
A short lens also has great depth of field so it’s good for street or action photographs. When responding to quickly unfolding scenes this depth of field lets you respond quickly without worrying about focus.
Short lenses also let you focus very close to your subject, and the effect this can have on the perspective in your images can be dramatic. Objects very close to the camera loom much larger than those farther in the background. This distortion in the apparent size of objects can deliberately give emphasis and when carried to an extreme, give an unrealistic appearance to a scene.
LONG, LONG AGO…
A long focal length lens acts somewhat like a telescope in that it magnifies the image of your subject. This is especially useful when you can’t get close to your subject— or don’t want to. Long lenses are ideal for wildlife, portrait, and candid photography, whenever getting close to a subject might disturb it. The long focal length lets you keep your distance and still fill the viewfinder frame with the subject. Keeping at a distance eliminates the exaggerated perspective caused by working very close to a subject with a shorter focal length lens. It also helps relax your subjects if they get uneasy, as many people do, when a camera comes close.
As the focal length of a lens increases, the depth of field gets shallower so you must focus more carefully. Also, a long lens visually compresses space, making objects in the scene appear closer together than they actually are. The primary drawback of a long lens is that most (but not all) such lenses have a smaller maximum aperture. This may force you to use a slower shutter speed. Also, since a long lens magnifies movement, just as it magnifies the subject, you may also have to use a tripod instead of hand-holding the camera. Fast lenses, shutter speed and the advent of image stabilized lenses have reduced the need for a tripod, however if you have a monster 400m f/2.8 lens attached to your pro DSLR camera, you are going to need a monopod, tripod or extremely strong arms!
THE SAME…BUT DIFFERENT
Canon and Nikon, with their vast arrays of lenses, have a real advantage over other camera companies that make DSLRs. Since developing a lens line-up is hugely expensive, there are only two ways companies can overcome this disadvantage:
The easiest way is for the company to license the lens mount from one of the leaders so their lenses work with your camera. Fuji has done this with Nikon so you can buy a Fuji camera and use it with Nikon lenses. Sony has also acquired Minolta and is using their lens mount in a range of new cameras and lenses.
A more expensive way is to join with other companies to share the costs of development. Olympus (along with Kodak, Fuji Photo Film, Panasonic, Sanyo and Sigma) are doing this with the Four Thirds System.
There are also independent third-party companies that make lenses for cameras. To reduce costs, their lenses can be used with more than one camera make just by changing the mount, sometimes using an adapter. Many of these lenses are quite good and usually less expensive than those from camera companies.
SOMETHING OLD, SOMETHING NEW…
Digital SLR cameras use electrical connections to set the lens aperture and adjust focus. When you upgrade to digital you can’t assume that your older lenses will work with your new camera. It depends on how old they are. Lenses with mechanical mounts definitely won’t work, but even some older lenses that have electrical connections may not work or lose some of their features.
Many camera companies that use smaller image sensors in their digital SLRs are introducing lenses designed specifically for these sensors. Because they create a smaller image circle, these lenses can be lighter and less expensive. However, if you ever upgrade to a model that has a full-frame sensor you won’t be able to use these lenses because the image circle will be too small to cover the sensor. Camera companies make this obvious by designing the lens mount so it won’t attach to a full-frame camera.
ADD SOME PUNCH!
If your camera has a fixed lens, you may be able to use lens converters to decrease or increase its focal length. There are two popular accessories for cameras with interchangeable lenses. Both fit between the lens and the camera body. Extenders extend the range of the lens. For example, a 2x lens converter will make a 100mm lens into a 200mm lens. Most interchangeable lenses also can be fitted with a teleconvertor. This will increase your focal length but will also move your f/stop up by two or three stops making your lens a little less functional for shooting action sports.
Commando Fact
A Macro lens is a specialty lens that allows you to get very close to a subject. Floral, insect and small item photography is its primary use. The catch is that macro lenses have a very shallow depth of field and therefore your focus has to be exact!
This post is an exerpt from Mike’s Commando Guide Cameras and Equipment. Sign up for our Newsletter and you get a complete free copy of the Commando Guide!
In happiness and health as always…
Mike C.
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