ibcrewin
Ah looky looky
I tried googling and yahooing this stuff to find an explanation with very poor results. Does anybody know of a resource that explains all this?
Thanks!
Thanks!
Xmas
Veteran
Wipedia should help
and if you exhaust all the hits
http://www.opticsinfobase.org/abstract.cfm?URI=josa-38-12-1032
Noel
and if you exhaust all the hits
http://www.opticsinfobase.org/abstract.cfm?URI=josa-38-12-1032
Noel
oftheherd
Veteran
Each peice of glass in a lens is called an element. When two or more elements are stuck together (usually glued) that is called a group. A lens with 4 elements, where for example, the 1st and 2nd are together, and the 3rd and 4th are together, would be a lens of 4 elements in 2 groups. If there were 3, with the 1st and 2nd together and the 3rd by itself, it would be a lens with 3 elements in 2 groups.
Googling aspherical gets:
An aspheric lens or asphere is a lens whose surfaces have a profile that is neither a portion of a sphere nor of a circular cylinder. In photography, a lens assembly that includes an aspheric element is often called an aspherical lens.
The asphere's more complex surface profile can eliminate spherical aberration and reduce other optical aberrations compared to a simple lens. A single aspheric lens can often replace a much more complex multi-lens system. The resulting device is smaller and lighter, and possibly cheaper than the multi-lens design.
Aspheric lenses are also sometimes used for eyeglasses. These provide clearer vision and a wider unaberrated field of view than conventional eyeglass lenses, and also distort the viewer's eyes less as seen by other people, producing better aesthetic appearance. The complex front surface curves from the center of the lens to the edge. With a prescription for the farsighted, the lens curve flattens toward the edge of the glass, and in the nearsighted, the surface becomes steeper to the lens edge, which offers vision superior to a conventional lens.
hope this simple explanation helps.
Googling aspherical gets:
An aspheric lens or asphere is a lens whose surfaces have a profile that is neither a portion of a sphere nor of a circular cylinder. In photography, a lens assembly that includes an aspheric element is often called an aspherical lens.
The asphere's more complex surface profile can eliminate spherical aberration and reduce other optical aberrations compared to a simple lens. A single aspheric lens can often replace a much more complex multi-lens system. The resulting device is smaller and lighter, and possibly cheaper than the multi-lens design.
Aspheric lenses are also sometimes used for eyeglasses. These provide clearer vision and a wider unaberrated field of view than conventional eyeglass lenses, and also distort the viewer's eyes less as seen by other people, producing better aesthetic appearance. The complex front surface curves from the center of the lens to the edge. With a prescription for the farsighted, the lens curve flattens toward the edge of the glass, and in the nearsighted, the surface becomes steeper to the lens edge, which offers vision superior to a conventional lens.
hope this simple explanation helps.
Film dino
David Chong
You may also find Erwin Puts' article useful:
http://www.imx.nl/photosite/leica/technics/optics01/lensdesign01.html
David
http://www.imx.nl/photosite/leica/technics/optics01/lensdesign01.html
David
ibcrewin
Ah looky looky
This is a great article. It's all begining to come together now. Great info. Noel, thank link needs a password but from the abstract it looks pretty interesting. OTH, that's what I thought it was but wasn't 100% sure.Film dino said:
Thanks everybody.