Lens what is focal length

FX format approx. A macro lens, used for close-up photography of small subjects like flowers and insects, lets the photographer get physically close to the subject and show it as larger than life within the frame.

Macro lenses can have a focal length ranging from 60mm to mm. The best focal length is the one that lets you maintain an appropriate distance from the subject. You can photograph unmoving objects like rocks, shells, and plants more easily with a shorter focal length, while moving subjects or living creatures are easier to capture with longer focal lengths.

The focal length of the lens impacts three key areas:. How much of the scene a lens shows to the camera sensor. Shorter lens focal lengths have wide angles of view, while long focal lengths have narrower angles of view.

Mid-length, around 50mm, have a similar angle of view to the human eye. The distance between the photographer and the subject, objects will appear smaller in images taken with short focal length lenses, and larger in those with longer focal lengths.

Is the distance between subjects in a scene. Longer focal lengths compress the distance, making it appear as if the foreground, middle, and background are closer together. Shorter focal lengths increase the appearance of distance between planes. Because cameras feature a variety of sensor sizes, not all models will tell you the true focal length of a lens. Lens focal length is based on a 35mm sensor size, based on 35mm film.

Most full frame camera sensors are the equivalent of 35mm, so a mm lens will actually have a mm focal length. This is an advantage when shooting in low light conditions as it will increase the possibility of hand holding the camera and freezing the subject without shake or blur caused by the longer exposures. Photographing using prime lenses with large apertures also means you can get a shallow depth of field which is useful for portraiture where you might want a softer or blurred background also known as bokeh.

Wide angle lenses are popular lenses for landscape photography , interiors, large group photos and when working in confined situations. Standard lenses are popular as they are closest to the angle of view we humans see. These lenses have minimal distortion, which can be flattering to the subject.

They tend to use large apertures and allow a lot of light to enter the lens which makes them fast in low light conditions. Standard lenses are the popular choice for a wide range of photography including portraiture, nature and low light situations where the photographer can not use a flash or is looking to capture the scene with available light.

Telephoto lenses between 70 — mm are very popular lenses for portraiture and product photography as well as nature and wildlife imagery. They allow the photographer to produce close crops on the subject. In the case of portraiture a telephoto allows the photographer to take the photo at a distance that does not intrude upon the subject.

These lenses provide a good range for wildlife and sports photography where the photographer is limited as to how close they can get to the subject. Lenses with shorter focal lengths also provide less magnification than those with larger focal lengths.

In addition to influencing the angle of view and magnification, focal length can also impact camera shake. Longer focal lengths are more susceptible to camera shake due to greater magnification — the tiniest movements become magnified and can result in blurred photos.

Generally, I recommend shooting with a shutter speed equal to or greater than the focal length as this can help prevent this from happening. Although not specifically a type of lens, aperture is another important feature of lenses. This is indicated in the format Some lenses will feature two maximum apertures shown as What this means is that as you zoom, the aperture capability changes.

Generally lenses with wider apertures are favourable due to their increased light capturing capabilities. There is also a category of lenses that feature a fixed aperture. Catadioptric, or mirror lenses, which used to be fairly common, usually feature a longer focal length, such as mm at a fixed aperture of f6. Most telescopes are catadioptric. However, at this point, it is important to mention that this could in fact be five.

This is because images can be recorded without a lens. Lens Focal Length and Picture Angle. Maximum Aperture Minimum f-number. Minimum Focus Distance. Depth of Field. Lens with a short focal length wide angle of view To view this content, JavaScript must be enabled, and you need the latest version of the Adobe Flash Player. Lens with a long focal length small picture angle To view this content, JavaScript must be enabled, and you need the latest version of the Adobe Flash Player.

Picture angle Focal length: 12 mm. Focal length: 24 mm.