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08-30-2010, 05:17 PM   #1
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Pentax MX metering issue

Hey guys,

Just got my MX back from Eric after a CLA. When it went in, the meter wasn't working at all. I got it back and now the top red LED in the viewfinder lights up no matter the aperture/shutter speed settings (indicating overexposure). For example, it does this at f/22 and 1/1000sec. Any ideas what the issue might be?

I've emailed Eric about it, but I figured I'd ask here as well.

Thanks!

08-30-2010, 05:23 PM   #2
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Found this thread, but no solution there: https://www.pentaxforums.com/forums/pentax-film-slr-discussion/39568-mx-lightmeter.html
08-30-2010, 05:52 PM   #3
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Try it in stop-down mode with one of your M42 lenses. That will give you an idea whether the meter is responding to different light levels and whether it is accurate if it responds.

If stop-down metering works, you might want to try using one of your other K-mount lenses. Remember that the MX requires a mechanical coupling between the aperture ring and the body and does not support the crippled Kaf mount.


Steve
08-30-2010, 05:59 PM   #4
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QuoteOriginally posted by stevebrot Quote
Try it in stop-down mode with one of your M42 lenses. That will give you an idea whether the meter is responding to different light levels and whether it is accurate if it responds.

If stop-down metering works, you might want to try using one of your other K-mount lenses. Remember that the MX requires a mechanical coupling between the aperture ring and the body and does not support the crippled Kaf mount.


Steve
I tried it with both my 43Lim and my A50/1.2, but I'll try with a M42 as well.

edit: no change with a Super-Tak 50/1.4

08-30-2010, 11:27 PM   #5
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QuoteOriginally posted by deadwolfbones Quote
I tried it with both my 43Lim and my A50/1.2, but I'll try with a M42 as well.

edit: no change with a Super-Tak 50/1.4
Back to Eric...
08-31-2010, 07:15 AM   #6
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Yep, that's what he said too.

Off it goes...
08-31-2010, 07:35 AM   #7
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Though I'll bet you already checked this stuff, and it may be nonsense, but just make sure the batteries are facing the right way and that ISO is isn't at 1600. Also check it in normal daylight. In low light on MX it's actually easy to go below the allowable meter coupling range and I think the meter does tend to indicate faulty readings either +1 or -1 (forgot which but found it kind of disturbing since most of my other cameras have wider coupling ranges).

For example, note that in the MX manual on page 22 the lowest coupled shutter speed at ISO 400 is 1/4 second. Meter behaves strangely if you exceed that...most newer cameras will continue to guess lower shutter speeds but probably with reduced accuracy...but MX won't even try to guess outside the range.

08-31-2010, 07:59 AM   #8
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QuoteOriginally posted by AndrewG NY Quote
Though I'll bet you already checked this stuff, and it may be nonsense, but just make sure the batteries are facing the right way and that ISO is isn't at 1600. Also check it in normal daylight. In low light on MX it's actually easy to go below the allowable meter coupling range and I think the meter does tend to indicate faulty readings either +1 or -1 (forgot which but found it kind of disturbing since most of my other cameras have wider coupling ranges).

For example, note that in the MX manual on page 22 the lowest coupled shutter speed at ISO 400 is 1/4 second. Meter behaves strangely if you exceed that...most newer cameras will continue to guess lower shutter speeds but probably with reduced accuracy...but MX won't even try to guess outside the range.
ISO/ASA are set at 200. I've tried it looking into a clear blue sky. I'll double-check the batteries, but wouldn't they just not light up at all if they were in the wrong way?

edit: switching the battery orientation indeed results in no lights at all.
08-31-2010, 05:43 PM   #9
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Sounds like something went wrong en route to you.
It happens. Send it back to Eric.

Chris
09-07-2010, 10:39 AM   #10
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I thought the MX meter failure had hit New Mexico twice this weekend, when my MX (also with Eric's CLA) stopped metering. It turned out to be the battery contact, which needed to be pried out a bit to make contact.

We'll see how well the Legacy Pro 100 did using variations on "sunny 16."
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