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11-01-2015, 02:12 AM   #1
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Join Date: May 2013
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K3II & Astrotracer 'odd' behaviour

Two countdowns with Astrotracer

Recently got a K3II and loving it. I have never don any astro photography before, but last night was lovely and clear so thought I would give it a go.

Followed the brief instruction in the manual and get odd behaviour. After firing the shutter (remote or 3s delay) the timer counts down the correct dialled in amount and the immediately starts another countdown with a 'nr' in the lcd display and a unrelated number of seconds countdown. only after this second countdown completes does the camera become responsive.

Anyone any thoughts?

---------- Post added 11-01-15 at 02:26 AM ----------

Seems i am able to answer my own question!
wasn't googling the right words.
I have 'Slow shutter speed NR' turned on and this is what is causing it.
So not a Astrotracer problem, just a general Bulb option

11-01-2015, 06:37 AM   #2
Sagitta's Avatar

Join Date: Feb 2011
Location: Maine
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"nr" is noise reduction.

The camera is nuking noise caused by the long duration of the shot. You can disable this in your settings if you wish - sometimes its actually a good thing to leave it off with astro shots because the camera can't distinguish between a star and a blip of noise.

EDIT: This is also why a 20 second shot in reality takes 40 seconds, or a 1 minute shot takes 2 minutes - the noise reduction is running a virtual dark frame of sorts internally in the camera so is processing that along with the actual shot.

EDIT: Posted before I saw you figured it out yourself.

In my experience shutting down NR is actually a good thing - sometimes. It depends on the conditions, your camera settings, etc...
11-01-2015, 07:35 AM   #3
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Join Date: Apr 2013
Posts: 244
If you got enough time and battery charge I would suggest leaving it on. It really helps to remove a bunch of noise. As this feature actually does a second exposure with closed shutter it should be able to distinguish between stars and noise. Test it and decide for yourself what results you prefer.

This feature really got me when I was unaware of it while doing lightpainting for the first time. My K-30 didn't show a message at all but only the "busy" light. I thought my camera was damn slow as others had their results way faster. But the results were worth it IMO.
11-01-2015, 08:10 AM   #4
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Join Date: May 2013
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Original Poster
cheers for the comments,
as it looks to b e a clear night tonight i may try again with and without to see how the results compare.

When i was doing this last night i couldn't see either screen so was perplexed why a 2 min exposure was taking 3+ with what seemed a 'pause' half way through.

I rarely read the Pentax manuals (started off with a k1000) , but the new features (at least to me) i would have like a bit more in the manual.

thanks again

11-01-2015, 09:35 AM   #5

Join Date: Dec 2011
Location: Nevada
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For night landscape and Milky Way images I turn on the noise reduction, otherwise I leave it off. For meteor showers you'll want the NR turned off and then do dark frame subtraction in post processing. Just do a web search for the term "dark frame subtraction."

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