The Micro Four Thirds camera system is blessed with a multitude of lens adapters which allow for fun and versatility in using almost any lens ever made – either via contrast detect AF within the camera if the lens is compatible for this or via manual focus.
The 43rumors team have posted a link to a new patent by Panasonic which appears to add phase difference AF capability when using Four Thirds lenses not capable of contrast detect AF.
See this pdf for details.
Unlike Olympus Micro Four Thirds cameras, the Panasonic bodies currently will not AF with a Four Thirds lens which is not contrast detect AF capable. (ps. the newest Panasonic bodies will now AF slowly even with non-CDAF OLympus lenses).
This new adapter would appear to address this issue by adding phase difference AF capability (similar as to technology used in dSLRs) – and perhaps allow sports level AF with such combinations.
The adapter will presumably be a Micro Four Thirds to Four Thirds adapter and use a pellicle mirror to deflect some light from the lens to a phase difference AF detector which responds to the user’s selected AF point via lens mount connections from the camera body and focuses the lens.
For compatible Four Thirds lenses, the user can select either CD-AF or PD-AF method.
If the lens is contrast detect AF capable, then the mirror moves out of the way and the camera’s contrast detect AF mechanism is used.
If the lens is not compatible with CD-AF or phase difference AF, then the mirror is moved out of the way and the user resorts to manual focus.
I think this is quite an exciting development as many Micro Four Thirds users will have or want to have Four Thirds lenses with a sports-capable dSLR such as an Olympus E-3, and this will allow them to gain AF when these lenses are used on their GH-1 or the new pro Panasonic camcorder for instance.
Of course, it is only a patent which may never eventuate, but I hope it does as it will provide additional options for us.
The extremely detailed but generic text of the patent suggests that this adapter may also work with a 2nd adapter – presumably similar to the recent Olympus patent – an adapter which includes AF lenses which not only can AF ANY manual focus lens but has a 2x wide converter to bring native field of view to the 2x crop sensor cameras – now this would be exciting indeed!