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05-24-2022, 03:25 PM   #1
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Pentax 6x7 with later model TTL prism inaccurate metering

I recently bought a Pentax 6x7 and separately bought a TTL "Pentax" metering prism. I very much prefer to meter through the camera than externally. I've found that #1: the meter doesn't move and is stuck on the bottom on MANUAL mode and #2: is working but inaccurate on AUTO. It seems to be pretty much always two stops under the correct reading. Do I need to get the camera serviced?

Edit: link to closed thread removed by moderator.

Last edited by Not a Number; 05-24-2022 at 04:08 PM.
05-25-2022, 09:41 PM   #2
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The meter doesn't work properly with the lens set at manual. At two stops off, hopefully the meter can be calibrated.
05-26-2022, 07:20 AM   #3
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You can get the TTL meter repaired, but I would return it if it's not working. Unfortunately these old TTL metered prisms are getting on in years and are prone to having issues.

Also have you checked the cameras linkage chain to the TTL meter, this can be a source of problems as well.


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645d, 645z, 6x7, camera, medium format, meter, model, pentax, pentax 6x7, prism, ttl, ttl metering
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