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Old 18th March 2009
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Re: Live view AF firmware upgrade for ZD 70-300

Quote:
Originally Posted by AndyElliott View Post
Agreed - most welcome - this ties in with recent comments about making sure all of the lens line-up will be imager-AF compatible.

Is there any technical reason why a lens wouldn't be able to use imager-AF? I assume the firmware update is about getting the correct set of parameters for a given lens to the body so that imager AF can work reliably (hence it isn't just a case of turning on a switch saying 'enable imager AF'!).

Andy
When the 70-300 was being designed, Olympus was already working on Imager AF, so it seems logical that the lens was equipped to work in this mode, but for some reason the fine tuning has only now been realised throught the firmware update.

The problem with earlier lenses and SWD lenses is that the gearing of the AF system was optimised for very fast and loong range changes in focus setting. This is how traditional phase detect AF works. When used with imager AF the focus mechanism can only move relatively slowly. If Olympus can make the AF optimisation of all their lenses switchable between Imager AF and Phase detect AF, that would be really cool!

Ian
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