Here are a couple of paragraphs taken from a Zeiss article that explains the Sony / Zeiss partnership arrangement regarding lenses.
Sony and ZEISS have had a very successful partnership for nearly 20 years. Photographers regularly ask us about our collaboration and the products that have been the fruit of our partnership. So in this article we answer the most frequently-asked questions and provide deeper insight into our cooperation.
In total, more than 185 million products carrying a common Sony/ZEISS brand have been sold since the partnership began nearly 20 years ago. Having “ZEISS” in the brand is one of the top five sales arguments for purchasing Sony/ZEISS products, and therefore an important distinguishing feature compared to competitors. According to Shigeki Ishizuka, Executive Vice President and Head of Imaging Products and Solution Sector at Sony, it is only natural that Sony will continue this close partnership. “We’ve learned a lot during 19 years of joint development with ZEISS. The knowledge we’ve gained has contributed significantly to developing Sony’s know-how in optical design and lens manufacturing. Together with ZEISS, we want to give our customers the ultimate photography experience, both now and in the future.”
Are lenses from ZEISS or Sony/ZEISS identical?
The lenses of the two lines are different, but optimized for the corresponding system. Because ZEISS’s know-how goes into every lens, both versions are highly sophisticated from a technical standpoint. Differences can be found in the focusing mechanism: for example, whereas Sony/ZEISS lenses always have autofocus, ZEISS offers a mix of autofocus lenses (e.g. ZEISS Batis) and manual focusing lenses (e.g. ZEISS Loxia). For the lenses of camera systems from other manufacturers, ZEISS relies mainly on manual focusing (ZE, ZF.2). Lenses that have the same focal length differ in their internal construction.
Where are the lenses manufactured?
ZEISS still picture lenses are manufactured in Japan and ZEISS cine lenses in ZEISS’s factory in Oberkochen/Germany. It is still economical for ZEISS to produce its cine lenses in Germany due to the more sophisticated skills required to manufacture these special lenses for the film industry. In order to satisfy the much higher global demand for still picture lenses, ZEISS has established a partner network in the optics industry. During the entire development and production processes, ZEISS experts ensure that the high quality standards for which ZEISS has been famous for over 165 years are met.
Sony/ZEISS lenses are manufactured by Sony in factories across Asia. In these factories Sony uses lens testing equipment that has been developed and manufactured by ZEISS. An example is the MTF-tester K8, a versatile and compact instrument used to measure the modulation transfer function of photographic lenses, or similar systems, at an infinite object distance.
For the complete write up please see Zeiss.