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A lens with a short focal length used to capture a wider angle of view.
A zoom lens offers a continuously variable focal length, normally without the need to refocus. A wide-angle zoom covers a range of focal lengths that include a wide angle setting. A standard zoom goes from a slight wide angle to telephoto and a telezoom covers a range of telephoto focal lengths. Some zoom lenses are called super zooms because they cover a larger range of focal lengths from wide angle to longer telephoto.
An electronic flashgun feature that allows the flash coverage to be adjusted. Flashguns are usually designed to cover the same angle as a standard lens, so when a wide angle lens is used you may find the edges of the frame are darker. A zoom head pulls closer to the flashtube to widen the angle and extends to throw the flash light out at a more concentrated angle.
Extreme wide-angle lens that gives 180 degrees coverage and is uncorrected for curvilinear distortion so you produce a heavily distorted photograph. If the photo turns out to be rectangular or circular, and how distorted it looks, depends on the lens and the camera. There are basically two kinds of fish-eye lenses for photography: 1. Lenses that produce a circular image, typically 8 or 10mm lenses, used on 35mm cameras or full-frame digital cameras. They produce a circular image with dark corners (due to most photos being rectangular). A similar lens is available for digital cameras with a so-called "cropped sensor". To achieve the same circular effect, it's a 4.5mm lens. 2. Lenses that produce a rectangular image. These lenses enlarge the image to cover the whole rectangular frame of a photograph. They are typically 15 or 16mm lenses. On a 35mm or digital full-frame camera they produce rectangular but still heavily distorted images without dark corners. The same lenses on a digital camera with a cropped sensor will still have a distorting effect, but less so. Fish-eye lenses used to be prime lenses only, but one company has gone so far as to produce a 10-17mm fish-eye zoom lens. This lens still produces distorted, curvy images, but zooming in lessens the distortion.
Also known as a reverse or inverted telephoto, this lens design has a diverging lens element positioned in front of the aperture and a converging element positioned at the rear. This makes the distance from the rear of the lens to the focal plane longer than the lens focal length. Retrofocus design has been adopted in wide-angle lenses so the rear of the lens does not impede the movement of an SLR camera's reflex mirror.
Bag-shaped bellows that are used to allow unrestricted camera movements with a wide-angle lens attached to a large-format view camera.
A camera designed for achitectural photography that has a wide angle lens mounted on a panel that moves up, down or sideways to correct perspective.
A lens that can be adjusted from one focal length to another. Wide zooms cover a range of wide-angle focal lengths while tele zooms cover telephoto ranges and superzooms go from wide angle to a long telephoto.
Indicates the magnification and angle-of-view of a lens. The human eye sees things roughly the same as a 43mm focal length of a lens for a 35mm camera. Anything shorter is classed as a wide-angle, while longer focal lengths are telephoto. Because of the comparatively small size of the CCD in a compact digital camera it has a standard focal length of between 6mm and 8mm while a medium-format camera is around 80mm.
This is the widest aperture that can be selected on the camera and is an indication of the speed of the lens. On zoom lenses two figures are often given. One is for the lens at the wide-angle setting and the other is for the telephoto setting.
Chromatic aberration, also called "colour fringing" or "purple fringing", is caused by a lens not focusing different wavelengths of light onto the precise same focal plane and/or by a lens rendering a different magnification each of different wavelengths. These two different types of chromatic aberration can both occur in one and the same image. Chromatic aberration can be seen as colour fringing around the boundaries that separate dark and bright parts of the image. It most frequently occurs around the edges of the image, especially in wide angle shots. Despite begin called "colour fringing" or "purple fringing", chromatic aberration can also affect black and white photography. Although a black and white image obviously has no colours in it, chromatic aberration can blur the image.
A technique where several pictures are exposed on one frame of film. This can be used for special effects such as shooting the same person so they appear twice in the same photo. Its also useful for shooting, say, a photo of the moon using a long lens and taking a second shot of a landscape with a wide angle. The two combined will look surreal. You normally have to do this manually and on cameras with automatic film advance it can be very tricky to achieve. Fortunately some cameras have an automatic multiple exposure mode.
A parafocal lens, after having achieved focus at a telephoto focal length, offers the possibility of zooming back to a wide angle length, meanwhile maintaining focus on the subject. Non-parafocal lenses have to be re-focused after zooming back.