| In return for their high price, specialist lenses can | | | | for serious wildlife photographers they are |
| make a huge difference to your photography. | | | | indispensable. An advantage of digital photography |
| With all these lenses, however, an SLR is essential. | | | | is that many digital SLR cameras effectively |
| Shift/tilt lenses | | | | increase focal length over their 35mm equivalents |
| The optical elements of a shift lens are mounted | | | | because of their small sensor size. Thus, a |
| on a mechanism that allows the lens to be raised | | | | 300mm lens can become a 450mm lens. Needless |
| or lowered from its normal shooting position. Tilt | | | | to say, a tripod is essential, even if you can |
| lenses contain a mechanism that allows the lens | | | | afford the top-grade lenses from Canon, which |
| to be rotated, to a limited degree at least, so that | | | | are equipped with image-stabilization technology. |
| it points upward or downward. A few lenses in | | | | Catadioptric lenses |
| this category combine both movements in one | | | | These lenses use a combination of curved mirrors |
| lens. | | | | (hence their common name of "mirror" lens) and |
| Shifting allows you to reduce or increase, say, | | | | glass lens elements in their optical construction, |
| foreground coverage without moving the camera. | | | | and are characterized by extreme compactness |
| Tilting the lens allows you to position the plane of | | | | in relation to their focal length - a 500mm focal |
| best focus, to give very deep or shallow depth of | | | | length, for example, can be folded into a barrel |
| field, without adjusting the aperture. These lenses | | | | barely 12cm (4% in) long. These optics usually |
| are ideal for architectural and landscape | | | | feature high correction for colour aberrations, |
| photography and are invaluable for still-life, | | | | irrespective of cost, and can focus at very close |
| tabletop work, and portraiture. | | | | subject distances. On the down side, all but one |
| Macro lenses | | | | model is manual focusing and they have only a |
| Turn to these lenses when peerless image quality | | | | single working aperture - the maximum - and that |
| is required. Available in focal lengths from 50 to | | | | is usually rather limited: a nominal aperture of f/5.6 |
| 200mm, these lenses focus very close and their | | | | or f/8 is usually the case. |
| level of image distortion is the lowest in general | | | | Steve J. Wilson is living in the United States and is |
| photography. Digital cameras do offer close | | | | a freelance writer since 2006, in digital |
| focusing, but usually at shorter focal lengths. This | | | | photography related topics. If you are interested |
| means that in order to obtain a magnified image, | | | | in some useful Digital Photography Class, than you |
| you have to work at close subject distances. | | | | are in the right place. |
| Super-telephotos | | | | Copyright © Steve J. Wilson, All Rights |
| Lenses with very long focal lengths are difficult to | | | | Reserved. All those who are interested in using |
| manufacture, so prices are usually high. However, | | | | this article, please make all the links active. |