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03-08-2015, 12:54 AM   #16
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Except this doesn't happen with the K-01.

03-08-2015, 09:42 AM   #17
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nuts

Maybe a squirrel thought you were looking as its food and wanted to change your focus ;').
03-08-2015, 09:54 AM   #18
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This may or not be relevant but what was the setting for your “Auto Power Off” setting. I know you said you were set for manual focus but if the camera was shutting off between shots maybe that had some sort of influence on the focus. Or does you setting the exposure to one every 5 minutes override that setting?
03-08-2015, 10:30 AM   #19
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QuoteOriginally posted by CWRailman Quote
This may or not be relevant but what was the setting for your “Auto Power Off” setting. I know you said you were set for manual focus but if the camera was shutting off between shots maybe that had some sort of influence on the focus. Or does you setting the exposure to one every 5 minutes override that setting?
that would be my question....if auto power off before the 5 minutes occurs it will turn off and then turn on I do not think the interval overrides the auto off time....if dust removal is checked on at start up then the sensor will shake and the Q will be trying to take the pic at the same time

03-08-2015, 12:54 PM   #20
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When my first test showed this shake at start up it also showed 'Dust removal' on-screen, so yes - I turned off this sensor cleaning on startup (mentioned in post#1).
Interval shooting always switches off the camera between shots with the exception of the timer. This saves battery power, though for indoor TL I have a Pentax ac adapter.
03-08-2015, 01:25 PM   #21
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so that eliminates auto power off having any effect on the Q then......................
04-15-2015, 09:53 AM   #22
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Simple test-use the same settings with the camera pointing forward, not down. This will eliminate any possible gravity-induced focus creep.
04-15-2015, 12:42 PM   #23
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Please read carefully: The lens was the 01 prime. There is no barrel to creep.

04-15-2015, 01:42 PM   #24
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QuoteOriginally posted by Steve.Ledger Quote
Please read carefully: The lens was the 01 prime. There is no barrel to creep.
No there isn't barrel creep like on a zoom but there are lens elements in there that are likely on some kind of helicoid that moves back and forth to achieve focus. If it's a focus-by-wire unit there is likely a small motor controlling the position of the moving elements.

Can you say with certainty that the moving lens elements did not move due to gravity?
04-15-2015, 02:07 PM   #25
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Thing is I did two short runs of a few hours each before the 25 hour marathon. Each time they were fine.
04-15-2015, 02:12 PM   #26
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QuoteOriginally posted by Steve.Ledger Quote
Thing is I did two short runs of a few hours each before the 25 hour marathon. Each time they were fine.
Maybe, but I'd imagine that there was a greater temperature differential in the 25 hour marathon than the short runs. Maybe the colder night caused a fraction of a millimeter change in the mating of two movable surfaces which then allowed gravity to play a role? Did the temperature change due to sunrise/sunset or some other factor during those first 14 shots?

Seems like the only way to rule out gravity completely is to conduct the same test in a manner where gravity cannot shift lens elements.
04-15-2015, 02:30 PM - 1 Like   #27
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I doubt the temperature had anything to do with it. This was shot inside the house where temps remain fairly constant. The earlier tests did not go out of focus after 14 shots and they were shot from mid afternoon to dark.
Thanks for your interest John, but I'm not going to bother wasting time in testing, if gravity is a factor then the Q can't be used to watch seeds sprout so I've just decided not to use the Q for time lapse again, the K-01 is far better.

---------- Post added 04-16-15 at 07:44 AM ----------

One of the tests:


This 11 second movie represents over 13 hours of shots (you can see how it get's darker due to the light from the window disappearing). If there was any temperature or gravity affecting focus, it would have done. It didn't, so this points to something random affecting the Q.

Last edited by Steve.Ledger; 04-15-2015 at 02:46 PM.
04-16-2015, 09:42 AM   #28
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Quite the mistery you have on your hands. Glad the K-01 could help. Watching grass grow has never looked better
09-15-2015, 03:04 AM   #29
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Hi,

I haven't read all the answers, but I've noticed something while doing some interval shootings. My K3 tries to autofocus between each frame. Maybe it's the same... Do not forget to switch to manual focus before you start your shoots ��
09-15-2015, 03:15 AM   #30
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You might want to read the first post ...
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