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08-12-2013, 02:19 PM   #16
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QuoteOriginally posted by Just1MoreDave Quote
I am not sure they could ever decripple the mount and make it work as well as people expect.
The main advantage of decrippling the mount would be that non-A contact K-mount lenses could be used in Av mode in the manner they were designed for. Unfortunately, given that Pentax no longer sells non-A contact glass, there is no incentive for them to do so. After all, cameras sell lenses, and if what the user buys is not made by Pentax...


08-12-2013, 08:06 PM   #17
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QuoteOriginally posted by stevebrot Quote
Even simpler than that. It is a simple on/off based ....
Nice! Thanks!
08-13-2013, 05:38 PM   #18
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QuoteOriginally posted by stevebrot Quote
Even simpler than that. It is a simple on/off based on the position/pattern of the contacts. The logic is essentially the same as a bit array in computer programming. See the table 2/3 down at the linked page below:

Features and Operation of the Ka Mount

Thanks Steve, I was going to add a different link to the same table.
The above link is to some research I did regarding using P-TTL controlled flash with pre-A series lenses. Basically it uses a technique where you make the camera think an M series or K series lens is an A lens. However, I also used the same technique to use manual f/stops on an A series lens. In theory, it should have made no difference if the lens is in the A position or manually setting the same f/stop on the lens (body told which f/stop used); in practice the histograms say otherwise. The pdf in the above link makes for interesting viewing.

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