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Canon continues to submit patent applications for an improved EF-M 15-45mm f/3.5-5.6 IS STM. The current version is inconsistent at best, some people get a great copy, but more often than not, one gets a poor copy.
This new design seems to use 12 elements instead of the 10 in the current design. The patent also touches on improved AF performance from the EOS M kit lens.
Japan Patent Application 2018169618:
The zoom lens used for an imaging device is a wide field angle, and the whole lens system's being small and a focus lens group can perform focusing at high speed by a small light weight, and, moreover, it is strongly requested on the occasion of focusing that there are few aberration variations etc. In order to make a focus lens group into a small light weight, it is necessary to lessen the composed lens number of sheets of a focus lens group. However, when the composed lens number of sheets of a focus lens group is lessened, the residual aberration of a focus lens group enlarges. For this reason, an aberration variation enlarges on the occasion of focusing, and it becomes difficult to obtain optical performance with a good rear spring supporter from a long distance to the object distance at large [ to a short distance ]
