Understanding Camera Lens Specs: A Beginner's Guide

Understanding Camera Lens Specifications: A Beginner's GuideThis guide is for new camera users looking to increase their understanding of lens definitions and technical specifications, and how this applies to taking pictures. I do not make lens regemendations as each user may have different needs, but the info in this guide can help you make your decisions. It is primarily for 35mm SLR lenses, but does include info about Digital SLRs and Medium Format lenses. This guide is very basic and if you are experienced Italized sections show important points.Definitions:Focal Length: The distance between the optical centre of the lens (the diaphragm) and the film. The distance is usually given in millimetres (mm), but on some older lenses it will be in centimetres (cm). The longer the focal length, the larger your subject will appear, and the shorter the focal length, the smaller your subject will appear. Large focal length lenses have small angles of view, and small focal length lenses have large angles of view.Aperture: A ratio defining the width of the lens glass with respect to the focal length. In simplest terms, it is a number that tells you the width of the glass inside the lens at the narrowest point. The smaller the number, the wider and faster the lens. These numbers can range from about 1:1 to 1:8 (f/1 to f/8), but most lenses fall between 1:1.4 to 1:4.5 (f/1.4 to f/4.5). A wide (or large or fast) aperture allows more light to reach the film or digital sensor, which allows you to take pictures with a faster shutter speed.Most 35mm