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Teşekkürler
Konuyu gündeme getirdiğiniz için biz teşekkür ederiz. aslında fiziksel ve yapısal özellikler için uzağa gitmeye de gerek yokmuş. Ken Rockwell yazmış:
Augustin Jean Fresnel (1788 - 1827) invented the basis of this technology in 1822. He realized you could collapse a lens like a collapsible drinking cup, but unlike the cup, the lens would work the same but without all the glass and weight.
Canon perfected it for use in photographic optics, and if you look at reflections of objects around you in the front element (not shown above), you can see that Canon has created the equivalent of an extremely thick, heavily curved element whereas in fact there isn't one. This allow the use of extremely low dispersion glass, which also has a low refractive index. The low dispersion reduces color fringes, but the low refractive index also require thicker, more heavily curved elements.
Canon has done such a great job of bringing this technology to photography that it's almost impossible to see the rings. To see them in the photo above I had to shine the sun at just the right angle to highlight them. I saw no other effects in actual photography, just the benefits of getting the optical equivalent of a highly curved aspherical surface without the weight or former expense.

Bir de gözlemlediği olumsuzlukları sıralamış:
Bad News:1.) Image Stabilization not good enough to give consistently perfect hand-held shots at 300mm at ISO 100 in daylight. The similarly priced Canon 70-200mm f/4L IS and half-priced Canon 70-300mm ISare much better.2.) Balky, congested zoom ring. Needs a separate hand to zoom. Other lenses zoom more easily.3.) Zoom is sensitive to elevation angle.4.) Soft at close range at 300mm, wide open.5.) Expensive, about $1,150 US as of July 2007.6.) Corny 6-bladed diaphragm.7.) Slow aperture. In actual use it's closer to f/5.6 throughout most of the zoom range than it is to f/4.