If you buy an average camera (by this I mean a lower end DSLR or a Point-And-Shoot), it will usually come equipped with a zoom lens. For some, this lens is great because they can just carry the camera with the attached lens and use the zoom ability to shoot either distant subjects or scenes.
For many professionals, zoom lenses are less than ideal. Yes, they eliminate the need to change lenses, but they introduce a couple of negatives:
• Zoom lenses have a number of movable pieces of glass to let it focus on subjects both near and distant. Thus, they are not as sharp as fixed focal length lenses.
• Zoom lenses don’t always carry the lens’ speed (largest aperture) throughout the zoom range.
This often means that if you use the camera on its AUTOMATIC setting, it will automatically pick a slower shutter speed if there isn’t enough light. This could result in pictures that are not sharp. An example: a zoom lens that comes with the camera might often have stamped on it the following (f/3.5 – 4.5 Zoom). This means that when the lens is used in its widest angle mode, its largest aperture is f/3.5, but when it’s zoomed out to its most telephoto mode, its largest aperture will only be f/4.5. Because f/4.5 is often not enough to shoot something in low light say, the camera will try to compensate by slowing down the shutter speed, thus giving you blurry images.
So, you need to pay attention to the cameras and lenses you buy. If you are just taking pictures as a hobby on vacation or of the kids or grandkids, a camera with a zoom lens might just be the thing. But if your tastes are a bit more discerning and you are looking for sharp images under most conditions, you might consider getting a DSLR with fixed focal length lenses, or a point-and-shoot with a good, fast zoom lens. A zoom lens that has only one f/ # indicates that it will carry that aperture throughout its zoom settings. A “kit” lens (one that is sold with the camera), is usually not as good as a separate zoom lens.
Also, when you use your zoom lens on its most telephoto setting, it’s always a good idea to use a tripod or some other means of support.
How To Get Great Results
From Your Camera’s Zoom Lens
by William Lulow