- Focus free lens
A focus free lens is a
photographic lens whose focal point is fixed at itshyperfocal distance . Rather than having a method of determining the correct focusing distance and setting the lens to that focal point, a focus free lens relies ondepth of field to produce acceptably sharpimages . Most cameras with focus free lenses also have a relatively small aperture which increases the depth of field.Camera s with these lenses generally use aviewfinder for composition.The advantage of this design is that it can be produced very inexpensively, more so than automatic or manual systems. The system is also effectively automatic; the photographer need not worry about focusing. It can also be more predictable than automatic systems.
Some disadvantages are that this type produces images that are less sharp than a lens that has been set to the best focal point for a given scene, and they are unable to produce sharp images of objects close to the camera, usually within 8-12 feet. The latter limitation makes them unsuitable for portraits, as they cannot fill the frame of an image with a person's face and render it sharp at the same time. This limitation is likely to confuse inexperienced photographers.
Focus free lenses are used in the lowest-end and cheapest cameras; disposable and low-end
point and shoot camera s. They are usually wide angle with fixedaperture .
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