The first reaction of some of the readers who are familiar with the common sense of photography is that of the “red circle”, which is, indeed, the high-end series in the good lens product, which always represents a higher optical quality and a better mirror. However, another high-end series in the jia energy lens is far less well known than the red circle, which is the green circle lens — a series of lenses with the gian do lens technology. I'm going to ask you today what's so great about the technology of the canon do lens and the green circle。
The role of solving problems such as colour dispersion
Let's start with cane do lens technology. Do lenses are called "diffraactive optics" meaning "multilayered distillation optical lenses". This technology has more excellent dispersive properties than previous spectroscopes and ud lenses, and the dual-layer do lens theory that can be developed on its own is the precision of the glass lens surface to create a distillation lens, creating a high-precision layered structure, thereby eliminating dissemble。
The dissemble of the do lens
Can't you see
In its history, the first camera to use the do lens is the ef 400mm f/4 do is usm, which can also be described as a sign of real market access for the ekdo lens technology; in addition to the ef 70-300mm f/4. 5-5. 6 do is usm; and the ef 400mm f/4 do is ii usm, which was updated in 2014, the ef 400mm f/4 do ii usm, which brought together three green circles. So what's the advantage of the do lens? Don't worry, we'll keep looking down。
• advantage to achieve small and light quantification of remote lenses
We know that when the light is refractioned in the lens, it produces color differentials and lowers the paint, and that, in order to compensate for it, multiple cones and dents need to be offset. As a result, a general remote or focal lens requires multiple lenses, which make the lens very large and difficult to carry。
Do lenses achieve small, light quantification of remote lenses
Unlike the technique normally used for calibration of colour differentials, do technology is based only on optical distillation and therefore requires only the use of cavity lenses, which not only simplify the various lens groups in the lens, but also effectively correct other imaging deficiencies other than colour differences. For example, while the ef 400mm f/4 do is usm lens (big green) is the same focal length and optical circle as the ef 400mm f/4 lens, “big green” is about 27% shorter in length and about 30% smaller in weight, achieving a small quantification of remote lenses。
The great green is much smaller in size and weight than the size lens
Small green also achieves small, light quantification as a remote-fired focal lens
Can't you see
Can't you see
Can't you see
In short, the energy-rich do lens technology can significantly reduce the size of the lens while eliminating the problems of dissembleding, imitation, etc., so that the heavy ultra-focused lenses can be small and compact. So, both large green and small green, the size and weight of which have a clear advantage in the lens of the same size, and it is for that reason that yoshinaga alone gave the do lens “green circle” a sense of visibility. If you have strict requirements for the quality and size of the lens, then a good green lens will be your first choice。
