Sigma patent shows Micro Four Thirds 25mm f/1.2 lens; could we see it some day from Olympus?
posted Sunday, April 26, 2015 at 4:35 PM EDT
A recently published patent from Sigma lays out the framework for two Micro Four Third lenses, one of which is already in production and one that may very well see the light of day.
Discovered by Egami, the patent details a single underlying lens design, with a total of six different embodiments, including f/1.8 lenses at 24.5, 25, 30, 17, and a second one at 24.5 with a slightly narrower field of view, plus a 24.5mm f/1.2. All use the same basic optical formula, comprised of 9 elements in 7 groups.
The essentially identical-looking optical formula used in Olympus’s M.Zuiko 25mm f/1.8 MFT lens suggests it's based on the design set out in Sigma's patent. The illustrations below show a diagram from the Sigma patent application on the left, and the M.Zuiko's optical formula taken from Olympus marketing materials on the right. (One possible difference; Specs for the Olympus 25/1.8 specify two aspherical lenses, while the Sigma patent seems to call for a total of five aspheric surfaces.)
Further support for the idea of a partnership or licensing arrangement between Sigma and Olympus comes from the similiarity between diagrams in Sigma patent application 2013-161076 and the published formula of the Olympus M.Zuiko 75mm f/1.8 lens.
Of course, the patent application discloses six different lens designs, and simply observing similarities between one of the embodiments and an Olympus lens is no indication whatever of Olympus' or Sigma's plans. It's still enticing to think about; regardless of whose brand the 25mm f/1.2 appears under, it would be a welcomed addition to any MFT users' lineup. On a full-frame sensor, the 25mm f/1.2 would be a 50mm f/1.2 equivalent; depth of field would be the same as a ~35mm f/1.6 on an APS-C body or a 50mm f/2.4 on a full-frame body. The current M.Zuiko 25/1.8 did very well in our testing; we look forward to a 25/1.2 based on the same design!