where h is the height of microlens, r is the radius of microlens, R is the radius of curvature of microlens, n is the refractive index for microlens material, and [Florin] is the focal length
For instance, a 50mm reducing lens placed at half the focal length
of the primary will have an effective aperture of 100mm for the whole system.
A higher focal length
, such as 200mm, is known as telephoto.
Sensitivity (f-number), or the eye's ability to admit light, was calculated using values for focal length
(F) and the diameter of the retina (d), measured from the extremities of the rhabdomeres in each species (Opell & Ware 1987).
Olympus also tackled the problem of eventually producing wide-angle lenses for digital cameras, since designs could be created without focal length
2mm focal length
, the lens provides an impressive 75.
One might now ask--if Digges had had access to optics similar in size and focal length
to those that I used, would he have produced a viable terrestrial telescope?
The 12 PTZ cameras have a variable focal length
of 5-550mm and have an additional pan and tilt option with a zoom capability that allows magnification of the image by 30 times (30x optical zoom).
Using a 1/4-inch interline transfer CCD, the camera features optical zoom focal length
As the water climbed the walls under various voltages, the curvature of its upper surface changed, modifying the lens' focal length
5B lens boasts a 24x zoom ratio with the highest magnification and longest focal length
in its class.
This produces a rounded lens with a small focal length
, so the drop can focus light only to a point near itself.