LYCOS RETRIEVER 
Lens: Systems
built 605 days ago
A common Gaussian form of the lens equation is shown below. This is the form used in most introductory textbooks. A form using the Cartesian sign convention is often used in more advanced texts because of advantages with multiple-lens systems and more complex optical instruments. Either form can be used with positive or negative lenses and predicts the formation of both real and virtual images. Does not apply to thick lenses.
Source:
PENTAX ... announced five new lens models all developed specifically for PENTAX digital SLRs bringing the complete line of lenses to 22 current models. Each new lens features a Quick-shift Focus System for instant switching from auto focus to manual and the PENTAX SP coating that protects the exposed lens elements from grease and dust.
Source:
Radio astronomy and radar systems often use dielectric lenses, commonly called a lens antenna to refract electromagnetic radiation into a collector antenna. The Square Kilometre Array radio telescope, scheduled to be operational by 2020[1], will employ such lenses to get a collection area nearly 30 times greater than any previous antenna.
Source:
MORE ABOUT
Systems