underwater Photo Course :: (2) Equipment Guide :: Underwater Camera Housings :: Lenses and optics :: Lens Types
Prime and Supplementary Lenses
U/W Photo Course
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Any lens attached directly to the camera body is known as a prime lens.
DSLRDigital Single Lens Reflex Camera. A camera that uses a mirror to redirect the image projected onto the film into the viewfinder. The mirror flips out of the way when the button is pressed to take the picture. camera lenses are prime lenses. Very few underwater cameras (notably the Nikonos) have prime lenses. Prime lenses are optically superior. The only
disadvantage of the prime lens is that once on the camera, whether in a housingA casing or box with waterproof seals designed to contain a camera or other equipment in such a way that it can be used underwater. or on an
amphibious camera, it cannot be removed during a dive (so you are stuck with looking for
subjects of the appropriate size).
a supplementary wide-angle lens
Supplementary lenses are additional elements that can be placed over a prime lens to alter focal length and angle of view.
They are optically inferior to prime lenses but have the advantage that they can be removed underwater
and you can therefore swap them during the dive to match the size of subject you
discover. This is the only way you can change the angle of view and focus distance on point and shoots (with their fixed lenses).
The Nikonos will take both prime lenses and supplementary lenses (over the 35mm standard lens usually bought with the camera body).
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