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10-15-2021, 02:21 AM   #1
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Pentax 645N not reading correct f-number

Hi all, I am new here.

Just got a second-hand 645N with FA45mm-85mm F4.5. However, when I tried using the aperture priority mode, no matter what f-number the aperture ring is set to, the viewfinder consistently shows only F4.5 and stays the same. The metered shutter speed also shows that based on F4.5

I read the manual of 645N which states: "The approximate aperture indication appears in the viewfinder. It may not the same indication as you select the lens aperture ring especially when the A645 150mm F3.5 or A645 45-85mm zoom F4.5 is attached "

Does it mean that
1. Aperture priority for this lens and camera is not possible?
2. Camera does not read the current aperture number?

PS. I tried dry firing in shutter speed priority with aperture ring set to 'A', it works fine, the aperture changes automatically with different lighting condition.

Helppp pls!


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45-85mm, 645n, a645, aperture, camera, f-number, f4.5, lens, mismatch aperture, pentax 645n, pentax help, photography, priority, troubleshooting, viewfinder
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