Field of view / Angle of view
The purpose of a lens or its focal length isn’t pyrotechnic experiments. Rather focal length determines the field of view (or angle of view), that is, the angle of subject area projected on the film.
A lens with a long focal length is usually called a telephoto lens and has similar qualities to those of a pair of binoculars. Telephoto lenses have a comparatively small angle of view and are quite useful when photographing distant objects since they enlarge the image on the film making the objects seem larger. Lenses with shorter focal lengths are commonly known as wide-angle lenses. Their angle of view is large but the objects, however, appear smaller and seem further away. The unit of length, which specifies a lens’s focal length, is the millimetre (mm). The most common format in photography is 35mm film. Most (digital) camera manufactures refer to this format when quoting focal lengths. When they refer to a wide-angle lens they usually mean focal lengths of 35mm or less. Lenses in the vicinity of 50mm are considered normal or ‘standard’ lenses and lenses with 70mm or more are considered telephoto lenses.
The focal length of the lens determines the image magnification of the photograph.
Each of the above-mentioned focal lengths has come to serve a different purpose. A standard lens has approximately the same angle of view as human vision. A moderately long lens (100mm) is a good alternative for portraiture because it allows you to photograph the subject at a distance while filling the frame, and it also avoids getting too close to the subject. Wildlife photography requires very long focal lengths (400mm or more). This is especially important because many animals are both small and far away. They might be somewhat shy when approached by humans or, in the worst of cases, be hungry and dangerous.
On the other side of the scale, wide-angle lenses are perfectly suited for snapshots and assignment photography where wide areas need to be captured. Wide-angle lenses provide a perspective not possible with the human eye. They are the best choice for photographing groups of people, architecture or landscapes while giving an increased feeling of depth.
Zoom lenses make you more versatile
Is it really necessary to carry various lenses with all kinds of different focal lengths in order to master every imaginable photographic situation? You’ll be surprised, but this used to be the case not too long ago. Nowadays, however, great improvements in optical engineering let us carry several focal lengths incorporated in only one lens, the zoom lens. It goes without saying that zoom lenses make life a lot easier, particularly if you think of the space you save and all the extra weight, which can now be left at home.
Another great advantage of zoom lenses is their swift focal length readjustment when an immediate comparison of different angles of view is required. This is especially important when composing an image if you have little time. Zoom lenses are available with different focal length ranges. Normal zoom lenses cover a zoom range from a moderate wide-angle to a short telephoto, e.g. 35mm to 70mm. Designing wide-angle zoom lenses with the widest zoom range below 35mm is no easy task if the required image quality needed in digital cameras is to be maintained.
Zoom lenses of the DiMAGE cameras cover a wide range of focal lengths, obviating the need to have several lenses.
As opposed to most digital cameras, Minolta’s DiMAGE 7 camera series is equipped with an exceptional 28mm at its widest angle. This is ideal for composing panoramic landscape shots or when photographing indoors. The optical zoom can be magnified 7x to a telescopic 200mm equivalent angle and the 2x digital zoom doubles the zoom range to 400mm.
The Digital Zoom
Many digital cameras fitted with an optical zoom offer an extra digital zoom. This non-optical zoom function simply reduces the field of view by cropping the image electronically and throwing in thousands of new pixels that were never there in the first place (interpolation). This function should be applied carefully because the final image’s resolution is reduced. The consequence is a loss of data. If you are not sure whether to activate the digital zoom or not wait until you get home and crop the image with the aid of a cropping tool included in your image editing software. The final results will practically look the same, without having lost any data.
* This content is taken from the konicaminoltaphotoworld.com website that was unfortunately taken offline. I take full responsibility for offering this here on dyxum but I honestly believe that this contests SHOULD be available to all Konica Minolta customers; this is the least they can do !