Tips for Purchasing a Digital Camera Lens
By: David Peterson

Your lens is an essential element to good photographs. It's not just your camera. People spend thousands of dollars on a good camera and neglect the lens.

Change that around! Make sure you buy a good camera lens when purchasing a camera. Buy a good camera as well, but don't neglect a good camera lens.

Why? Your camera is just the 'holder' for the photograph. The lens is what your camera sees all your shots through. A good lens is essential to clear and sharp photos.

With most compact digital cameras, you can't change the lens. So in that case, don't just buy a good camera, ensure it also has a good lens.

Avoid a plastic digital camera lens because it doesn't have the clarity of a glass lens.

What model of lens?

Stick with camera lenses from well known manufacturers like Nikon, Canon and Pentax. Ensure you purchase a lens that works with your camera too. A Nikon camera lens usually won't work well with a Canon camera.

There are specialty lens manufacturers like Carl Zeiss, Leica and Leupold. If you're a beginner, don't worry about these lenses until you are more advanced as they come with very high prices and it's hard to justify the price for the small increase in quality.

Types of Camera Lens

The most common lenses are : Wide Angle, Normal and Telephoto. The type of lens is determined by the Focal Length of the lens. See below. A Zoom Lens is simply a lens that can change Focal Length from a Wide Angle to a Telephoto (or somewhere inbetween).

There are a number of things to look for when purchasing a camera lens.

Lens Focal Length

The Focal Length of a lens determines the amount of magnification and angle of vuew the lens can see. The Focal Length is measured in mm. It's the Focal Length that determines if the lens is a:

- Wide Angle; small magnification, wide angle of view. 20mm to 35mm

- Traditional, or Normal; 50mm

- Telephoto; high magnification, narrow angle of view; 105mm to 300mm.

- Zoom; A Zoom lens can change it's focal length to zoom in. A Zoom lens might have a Focal Length of between 50mm and 150mm.

Some lenses are interchangeable between film cameras and digital cameras, but you need to be aware that the effective focal length CHANGES between film and digital. The focal lengths I describe above are for FILM cameras and need to be multiplied by 1.6 to get the effective focal length on a digital camera. So using a film 35mm lens on a digital camera has an effective focal length of 56mm.

What does this mean for you? It means that you won't get as wide angle on a digital camera as you would on a film camera using the same lens. A 35mm lens which gives a medium wide angle on a film camera acts as a traditional lens on a digital camera

This is a complex subject, so I can't go into too much detail here. If you need more help, the best person to speak to would be your local camera store's resident expert.

Lens Speed

The 'speed' of a digital camera lens also defines a lens. The speed is determined in f-stops and is similar to the f-stop aperture setting on your camera. Faster lenses are more expensive and usually heavier.

Focusing Distance

This is the minimum distance from the camera lens that a subject must be to be in focus. Don't worry about getting a camera with a close focusing distance. Concentrate on a telephoto instead.

More Advanced Features

More expensive lenses have more advanced features.

- Vibration Reduction. A feature called 'vibration reduction' keeps images sharper when shooting in low light. They help to counter any vibration in the camera. Try to find a digital camera lens with this feature.

- USM USM stands for Ultrasonic Motor. This feature of Canon lenses gives you a high speed auto focus but the main benefit is the 'motor' is almost silent, so you don't disturb people around you when your camera is focussing.

- Filter Thread. When purchasing a half-decent lens, it should have a filter thread. This is a thread that allows you to screw on a filter (such as a polariser) to help when photographing difficult situations. Even if you don't need filters right now. it's handy to purchase a lens with a thread so you can add a filter later.

You get what you pay for

Generally the more expensive the lens, the better it is. More expensive lenses usually have a higher number of glass elements in the lens, which also makes them heavier.

Final Notes

While it is important to choose good quality camera lens, for beginners it isn't as important as good composition. Don't fall into the trap of thinking you can only take a great picture with an expensive top-of-the-line lens. A badly composed picture won't look great with a great camera lens.

I don't mean to discount the importance of a good quality lens. A good rule is to only add to your lens collection only when you have a specific need for a particular digital camera lens.

Do your research and your homework first, and find the lens that suits both you and your camera.

David Peterson has a great love of photography and has created a series of free tips at http://www.digital-photo-secrets.com/ to help digital photography users everywhere take better photos.