03-30-2015, 04:19 PM
Regarding Sony / Sony-Zeiss / Zeiss-
Zeiss is partnered with Sony. They exchange resources. A zeiss-badged sony lens has had some level of Zeiss involvement in the design but most likely was not designed entirely by a Zeiss lens designer or lens design team. Zeiss may be concerned about rep, but also maybe not - consumers are incredibly "easy" on camera optics in that typically most anything looks/performs just fine to them. Zeiss has a greater goal of brand recognition than namesaving right now.
Regarding astigmatism and the like - A typical but arbitrary number is that light from over 200 focal lengths away is effectively at infinity to a very good approximation. The test chart is probably closer than 14m for the 70mm test, so it is within the failure range of this approximation. As a lens is refocused, performance often changes significantly. I do believe astigmatism and CAs are the chief problems in the images here, as the images do not reflect a high level of spherical aberration, oblique spherical, or coma. This leaves only astigmatism and polychromatics to be the big problem.
Zeiss is partnered with Sony. They exchange resources. A zeiss-badged sony lens has had some level of Zeiss involvement in the design but most likely was not designed entirely by a Zeiss lens designer or lens design team. Zeiss may be concerned about rep, but also maybe not - consumers are incredibly "easy" on camera optics in that typically most anything looks/performs just fine to them. Zeiss has a greater goal of brand recognition than namesaving right now.
Regarding astigmatism and the like - A typical but arbitrary number is that light from over 200 focal lengths away is effectively at infinity to a very good approximation. The test chart is probably closer than 14m for the 70mm test, so it is within the failure range of this approximation. As a lens is refocused, performance often changes significantly. I do believe astigmatism and CAs are the chief problems in the images here, as the images do not reflect a high level of spherical aberration, oblique spherical, or coma. This leaves only astigmatism and polychromatics to be the big problem.