Friday, January 12, 2007
Wide-Angle Lenses For Digital
Yes, you can do wide-angle photography with a D-SLR!
Next, consider lens speed, special elements and focusing mechanism. Faster lenses are easier to focus manually in dim light and autofocus more quickly. They also provide a brighter viewfinder image for easier composing. But they cost considerably more than slower lenses of equivalent focal length. If you do a lot of low-light shooting, a faster lens will be worth the extra cost; otherwise, probably not.
Low-dispersion elements (identified by designations such as ED, LD, ELD, HLD, SLD, UD and SUD in the lens name) minimize chromatic aberrations and thus provide sharper images. Aspherical elements reduce spherical aberrations and edge distortion and provide more even illumination across the image area, providing better resolution and contrast, minimizing the curving of straight lines at the edges of the image and reducing darkened image corners and edges.
Internal- and rear-focusing systems move elements inside the lens instead of extending the front elements away from the camera body. In wide-angle lenses, internal focusing offers several advantages: The front element doesn't rotate during focusing, handy when using orientation-sensitive lens attachments such as polarizers and graduated filters; moving smaller internal elements rather than heavier front ones makes for quicker autofocusing; and minimum focusing distances can be reduced. Aspherical elements and internal/rear focusing also allow for more compact lens designs.
Getting the Most from Wide-Angle Lenses
A wide-angle lens will take in a large slice of the scene before the camera. The biggest faults in wide-angle shots are lack of a center of interest and clutter. A wide vista with no visual center lacks impact, and the viewer's eye tends not to know where to go. A landscape shot with interesting cloud formations or reflections in a lake can be lovely. But since it's all at a great distance, the resulting image will have a flat perspective. After you shoot such a scene, look for an angle that includes a foreground subject that can add depth to the image-a tree or a rock formation. You can even position a travel companion strategically in the shot to add depth. Try to keep your wide-angle compositions as simple as possible. Too many elements in the picture just confuses the viewer.
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