Focal length refers to the magnification of a camera lens. While discussion of focal length can get very technical, for the purposes of this article, we will keep it in simple!
There is a focal length that is considered “normal’ for each digital camera. Generally, normal is what is considered normal viewing when a photo is printed. For a 35mm camera, the normal focal length is about 50mm. Any focal length less than that is “wide angle,” and any focal length longer than 35mm is telephoto.
When speaking of point and shoot cameras, they come with a lens as part of the camera. The lens will have a set focal length, but in most cases, it will be a variable or zoom lens with more than one focal length available. The usual terminology of a point and shoot camera will indicate that the camera is 3x or 5x for example. This means that the focal length of the camera’s lens has a range that extends from it shortest focal length to its longest focal length.
An example of a point and shoot camera is a Canon PowerShot, which has a 4.2x zoom lens. The lowest, or wide-angle, focal length is equivalent to 28mm (in 35mm camera terms), and the longest focal length for the S95 is 106mm.
Point and shoot cameras come with lenses that are about 4x all the way up to 30x. The higher the zoom range, the more flexibility the photographer has with respect to the type of shots they can capture. However, something has to suffer to get that high super-zoom ability, and it is usually the image quality. It is quite hard to get image quality in a 30x camera that is equal to the quality of a 5x zoom camera, all other things being equal.
When it comes to focal length and digital SLR cameras, there is plenty of diversity and many choices. One of the beautiful things about digital SLRs is the fact that the photographer has such a wide range of choices when it comes to lens selections. Many pro photographers claim that using single, or prime, focal length lenses will give the very best quality. Others contend that zoom lenses are up to par with prime lenses.
Different types of photography lend themselves to different focal lengths, and, hence, different point and shoot cameras or lenses for DSLR cameras. For example, the photographer who wants to concentrate on landscape photos will probably choose a focal length that is wide-angle. Those who specialize in portrait photography will most likely go for a telephoto focal length between 50mm and 100mm. And sports and nature photographers go for the big guns, the super-telephoto focal length lenses of 300mm and higher.
It should be noted here that the stated focal length of a lens or camera is not always the actual focal length you will get in the photo. The most obvious situation is in digital SLR cameras that have something know as a “crop sensor.” A crop sensor is one that actually magnifies the photo by a factor of about 1.5x when compared to an actual 35mm camera. Therefore, a digital SLR camera equipped with a 100mm lens yields pictures equal in size to a full-frame camera equipped with a 150mm lens.
All things considered, you should really know what type of photos you want to specialize in before selecting the digital camera that you will be using to take those pictures. Focal length plays a major part in selecting the camera and the lenses.