Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
08-20-2013, 06:53 AM   #1
Site Supporter
ebahle's Avatar

Join Date: Oct 2011
Location: Northern Michigan
Photos: Albums
Posts: 180
bulb mode random shutter times

Sorry guys if I am repeating another thread. I couldn't find one like this.

So i was out trying to capture the meteor shower and my k7 started acting very strange. I was trying to leave the shutter open for 150 to 200 seconds. But when the shutter would supposedly close the camera would lock up and not let me take another photo until i power cycled it twice. Yes I have slow shutter noise reduction turned OFF. Additionally when i would look at the photos they would have completely random shutter lengths on them. i.e. 1/5th, 46sec, 30sec but never the full time i had programed into my remote.

Side note, I ditched the programable remote and tried the IR remote, same result, ditched IR remote and just tried using shutter button, same result.

Am I not understanding something here? Broken or bad equipment?

08-20-2013, 07:07 AM   #2
Site Supporter




Join Date: Jul 2009
Location: Mount Joy, PA
Photos: Gallery | Albums
Posts: 528
Was your battery running low at the time, by any chance? Low batteries have caused a myriad of strange camera behavior for me, even though the cells weren't on their "last gasp", so to speak.
08-20-2013, 07:14 AM   #3
Site Supporter
ebahle's Avatar

Join Date: Oct 2011
Location: Northern Michigan
Photos: Albums
Posts: 180
Original Poster
I had a grip (genuine) with one fully charged and a partial charge in the other. With a grip will it fully drain one battery before moving onto the second?
08-20-2013, 07:15 AM   #4
Pentaxian




Join Date: Mar 2010
Location: Frankfurt am Main
Posts: 1,044
As LowVoltage states, power supply may be the culprit.

Even if batteries are freshly loaded and still good enough for standard shooting, they may not deliver anymore when constantly draining for minutes, without any short pauses for recovering.

For extensive use of long bulb times, you probably need batteries in the first half of their life time.

EDIT:
With a K200D, you can select in the settings whether using both grip and built-in simultaniously, or let the camera switch automatically only after one of them is really empty. About other Pentax bodies, I don't know.
The function to use both at the same time needs additional circuits to prevent one package draining the other, and this system may still not work perfectly if load and/or health of the two are very different.


Last edited by RKKS08; 08-20-2013 at 07:22 AM. Reason: Information added
08-20-2013, 07:16 AM   #5
Site Supporter
ebahle's Avatar

Join Date: Oct 2011
Location: Northern Michigan
Photos: Albums
Posts: 180
Original Poster
hmm, ill have to play with it a little, but i seem to remember this happening before on fresh batteries
08-20-2013, 07:46 AM   #6
Pentaxian
calsan's Avatar

Join Date: Nov 2008
Location: Perth, Australia
Photos: Gallery
Posts: 1,367
Slow speed shutter noise reduction cannot be turned off on the K7 when the shutter speed is longer than 30 seconds. So that's the problem. See manual page 92!
08-20-2013, 07:54 AM   #7
Pentaxian
emalvick's Avatar

Join Date: Feb 2008
Location: Davis, CA
Photos: Gallery
Posts: 1,466
I have had similar problems on occasion and remember the problems being a combination of battery and temperature. If the temperature is getting quite cold (around freezing or lower), the batteries will behave as if they have a low charge even when freshly charged. I used to have this problem all the time with the K10d. The problem does not occur as much with my K5, but I did find that I needed to remove the grip because the camera would want to change batteries back and forth due to detecting a low setting. However, the images and times would work out ok with that camera.

Unrelated: I once had problems with my remote because I would have to hold it down or the remote itself would detect things oddly. It would read a press even if I hadn't pressed and other related "malfunctions". I ended up purchasing a small wired remote with a small clamp that let the trigger be pressed and held. I usually just let the remote hang while I time the shot and unclamp the button when I'm happy with the timing. This remote allowed the problems to go away. The remote I got was something like $2 from ebay (one of those Hong Kong made products). It has held up pretty well, and for $2 I was willing to take the risk. I've liked it better than all other remotes I've had, and it saves me from the wobble of using the shutter itself.
08-20-2013, 07:57 AM   #8
Pentaxian
maxfield_photo's Avatar

Join Date: Mar 2011
Location: Cincinnati, OH
Posts: 1,216
QuoteOriginally posted by calsan Quote
Slow speed shutter noise reduction cannot be turned off on the K7 when the shutter speed is longer than 30 seconds. So that's the problem. See manual page 92!
I think it can be, but you have to do it from the debug menu, or maybe that's just on the K20d. Perhaps someone can post the procedure.

08-20-2013, 10:42 AM   #9
Veteran Member
Kendigitize's Avatar

Join Date: Apr 2013
Photos: Gallery
Posts: 316
What is the advantage to having the Slow Shutter noise reduction turned off? Is that why my 5min exposures take 5min to process? (I have a k-30 and a shoot raw)
08-20-2013, 10:48 AM   #10
Site Supporter
JimJohnson's Avatar

Join Date: Jan 2012
Location: Lake Superior - Michigan
Photos: Gallery
Posts: 2,164
QuoteOriginally posted by Kendigitize Quote
What is the advantage to having the Slow Shutter noise reduction turned off? Is that why my 5min exposures take 5min to process? (I have a k-30 and a shoot raw)
Yep. dark field subtraction. Intended exposure followed by equally long exposure with the shutter closed; processor subtracts whatever the sensor sees in the second exposure from the intended exposure.
08-20-2013, 12:57 PM   #11
Veteran Member
Kendigitize's Avatar

Join Date: Apr 2013
Photos: Gallery
Posts: 316
QuoteOriginally posted by JimJohnson Quote
Yep. dark field subtraction. Intended exposure followed by equally long exposure with the shutter closed; processor subtracts whatever the sensor sees in the second exposure from the intended exposure.
Thanks! I knew I was doing something wrong. Is it best to leave the setting on auto most of the time and just turn it off for long exposures?
08-20-2013, 10:47 PM   #12
Pentaxian
calsan's Avatar

Join Date: Nov 2008
Location: Perth, Australia
Photos: Gallery
Posts: 1,367
The solution to very long exposures on the K7 is:
Do multiple 25 second exposures (Slow Shutter noise reduction turned off) and then use software to stack them.
08-21-2013, 04:21 PM   #13
Pentaxian




Join Date: Mar 2010
Location: Frankfurt am Main
Posts: 1,044
Just in case you don't know what may happen if you turn Slow Shutter Noise Reduction off:

The discrete cells of a sensor should only react on light. But Physic says this is impossible (except at temperatures near absolute zero). So occasionally a pixel will be activated even without any light. With higher temperatures the numbers of such pixels will increase, and with long exposures the sensor gets much hotter than it usually is. Which of the pixels will act this way is not completely randomly - some will act always earlier than others. If the sensor is now activated for an equally long time with closed shutter, it will have roughly the same temperature, and most of the pixels "lighted" will be the same as with the exposure done before. The processor will replace these values by subtraction or interpolation from neighbouring pixels (I am not sure which strategy Pentax uses).

If you switch off this special noise reduction, you may see hundreds of tiny coloured points all over the frame. There are functions to remove them in post, but for astro shooting these functions could well also eliminate some existing real stars.
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
bulb mode, ir, pentax help, result, shutter
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Bulb mode question Smilesy Pentax K-r 9 08-19-2012 08:22 PM
Bulb mode acting strange 123jippo Pentax K-5 8 08-06-2012 02:55 AM
*ist DL2 Bulb Mode fraank Troubleshooting and Beginner Help 4 05-14-2012 04:53 PM
Bulb mode MrK5 Pentax K-5 11 01-25-2012 05:52 AM
Time Exposure - Bulb setting - Read write times Vatis Pentax DSLR Discussion 7 09-05-2007 07:38 AM



All times are GMT -7. The time now is 12:11 AM. | See also: NikonForums.com, part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top