Lens maker Zeiss has written a blog post about its relationships with other manufacturers - specifically its partnership with Sony. The post sheds some light on exactly what that little blue logo on your lens might mean. The blog post itself appears to have been written by the marketing department at Zeiss, but reading between the lines gives us a better idea of how the company's relationship with Sony works.

Lens makers' names appearing on lenses can mean a variety of things. It can mean anything from 'this lens has been designed and built by a respected manufacturer' through to 'the company selling the lens has paid a license fee to whoever holds the rights to a respected name'. This variety of meanings helps explain why Samsung's GX-mount Schneider Kreuznach-branded lenses looked identical to Pentax's range of K-mount lenses.

The Zeiss blog suggests a relationship with Sony somewhere between these two extremes. It makes clear that there are several distinct lines of lenses that carry the Zeiss name: the Cine range of lenses built in Germany, the manual focus rangefinder and DSLR lenses made in Japan*, the recent named Zeiss ranges (Loxia, Batis, etc.), and the jointly-branded Sony/Zeiss autofocus lenses. In addition, Microsoft, through its ownership of Nokia's mobile phone business, also makes some Zeiss-branded products.

Of the Sony/Zeiss lenses, the blog says: 'ZEISS supports Sony throughout the optical design and development process and then tests and approves the prototypes.' Which noticeably doesn't even say that Zeiss is particularly involved in the design process, just that it gets to approve whether the design is of a high-enough standard to bear its name.

...it works to ensure lenses carrying the Zeiss name are consistently built to a standard
that the company would be happy with.

The different Zeiss lenses are then built by a variety of manufacturers, with Sony making Sony/Zeiss optics in 'factories across Asia.' Zeiss says it supplies testing equipment to these factories, sets the technical and quality standards to which the factory must adhere, examines the production processes, management systems and measuring installations and regularly audits the production process. In other words, it works to ensure lenses carrying the Zeiss name are consistently built to a standard that the company would be happy with. This is a long way from simply letting a manufacturer pay to use the name.

This pattern is also consistent with what we've been told about Panasonic's relationship with Leica.

The final point we found interesting was the explanation that: 'Sony and ZEISS each follow their own product strategies depending on market and quality needs.' If nothing else, this helps explain the distinction between Sony/Zeiss-branded 'ZA' lenses, the Zeiss Touits and the Zeiss Batis lenses, and why they all co-exist for Sony's cameras. It also explains why the Sony-developed ZA lenses are not available for any other mounts.

* The manual focus Zeiss lenses for M-mount, ZE-mount (Canon EF) and ZF.2-mount (Nikon F) appear to be made by Cosina, though the nature of this relationship isn't touched upon in the blog post. It's interesting to note that Cosina does not promote the Touit, Batis or Loxia ranges of lenses, though all of these are also made in Japan. Japan has a number of third-party lens makers with experience of making autofocus lenses for other brands - our suspicions would point towards one of those.