Interval Shooting question(s)

Trig · 02-23-2012, 11:33 AM

So I set up my trusty K-5 to do some interval shooting to capture some star trails. I am close to the city so I kind of have to go with interval shooting to help with the city lights flooding a long exposure shot.

Here were my settings:

Manual exposure at shutter speed of 30s
Interval shooting set to: 00:00'31" (I set it to 31 seconds to give it 1 second to write to the card)

Over 115 minutes of shooting, I got about 112 shots. This equates to about 1 exposure per minute. When I tried this at home to sit and watch the camera during this, it takes a shot over 30 seconds, then waits 30 seconds, then takes another shot. Yes, I read the recently posted article here of Pentax Forums.

So, any clue what I could be doing wrong. The SD card is pretty darn fast and it sure doesn't look like it is stalling to write the image that could be throwing off the interval.

Here is what the image looked like. You can clearly see the 30 second pause between exposures as evident of this really wide angle shot at 8mm. I assume that even with a second gap between exposures the "gap" would be seem as less at a wide angle such as this.

Any suggestions out there?

demp10 · 02-23-2012, 12:02 PM - **1 Like**

You are not doing anything wrong. When you take a long exposure, the camera does some processing to remove noise. Essentially it takes the same exposure with the shutter closed and then subtracts the "black" frame that has sensor noise only. That way the resulting image has significantly less noise. So for your 30sec exposure, there is a 30sec "correction".

Trig · 02-23-2012, 12:05 PM

Hmmmm...that is what I thought but I made sure I had that correction turned off on the camera. I normally do noise reduction in PP.

Unless, it does the dark frame noise reduction when using interval timing and you cannot turn it off when using interval shooting?

Trig · 02-23-2012, 12:18 PM

Originally posted by demp10

You are not doing anything wrong. When you take a long exposure, the camera does some processing to remove noise. Essentially it takes the same exposure with the shutter closed and then subtracts the "black" frame that has sensor noise only. That way the resulting image has significantly less noise. So for your 30sec exposure, there is a 30sec "correction".

You are correct. When shooting using interval shooting, it seems the dark frame reduction (noise reduction) cannot be shut off (even if you have it selected to be off). When I shoot at 25s, it works perfectly at a interval time of 26s.

Thanks so much demp10!

ofer4 · 02-23-2012, 02:00 PM

Trig/demp10... I'm not sure that I follow this. Is this behavior specific to the K-5? I don't think I've seen it with my K-r. Also, Trig, is your last post saying that <30 sec exposures remove this behavior? Thanks!

demp10 · 02-23-2012, 02:47 PM

The K-7 manual states that even if the Slow Shutter Speed NR is off, it will still operate in B mode and when the shutter speed is more than 30 sec.

**Ex Finn.** · 02-23-2012, 04:50 PM

K5 is supposed to be a different animal as far as DFS. Even with the caps, that is a one cool shot.

imtheguy · 02-23-2012, 05:53 PM

Just to make sure I understand this back and forth.....The k-5 WILL shoot in interval mode WITHOUT DFS (if its turned off in the menu) if the shutter speed is less than 30s? I just tested and know for sure it allows DFS to be off at 25s. Since only Bulb can exceed 30s I thought I missed the point here. Did I?
Thanks folks.

**Ex Finn.** · 02-23-2012, 06:14 PM

Didn`t one of the latest FW updates take care of the DF subtraction issues while shooting in bulb?. I never shoot star-trails so not much first hand help here.

Trig · 02-23-2012, 06:40 PM

Originally posted by demp10

The K-7 manual states that even if the Slow Shutter Speed NR is off, it will still operate in B mode and when the shutter speed is more than 30 sec.

I am not shooting in bulb mode. I am shooting in Manual mode. If I take "continuos" shots of 30s, there is no delay as I see when shooting during interval at 30s exposures so it seems to me the DFS automatically gets turned on when shooting in interval.

Originally posted by Ex Finn.

K5 is supposed to be a different animal as far as DFS. Even with the caps, that is a one cool shot.

I am certain I have the DFS turned off.

Originally posted by imtheguy

Just to make sure I understand this back and forth.....The k-5 WILL shoot in interval mode WITHOUT DFS (if its turned off in the menu) if the shutter speed is less than 30s? I just tested and know for sure it allows DFS to be off at 25s. Since only Bulb can exceed 30s I thought I missed the point here. Did I?
Thanks folks.

My K-5 shooting in Interval with DFS off up to 25s in manual mode. When I get to 30s exposures, the DFS automatically activates in Interval Shooting. I am not shooting in Blub for all this, just manual.

Originally posted by Ex Finn.

Didn`t one of the latest FW updates take care of the DF subtraction issues while shooting in bulb?. I never shoot star-trails so not much first hand help here.

Yes, you can turn the DFS off and on, it just seems to come on (even with it selected to be off) when shooting in manual at a exposure of 30s.

Thanks for all the input everyone. Sincerely appreciate it! At least all I need to do it set the exposure down to 25s and I should have very minimal gaps in the trails with a wide angel. Thanks!

walter · 02-23-2012, 11:09 PM

Have you tried setting the interval to 32 seconds? That seems to work for my K-5, without skipping shots. With these settings, it sounds like the next photo triggers almost immediately, I don't hear a 2 second pause between shots.

Trig · 02-24-2012, 06:17 AM

Originally posted by walter

Have you tried setting the interval to 32 seconds? That seems to work for my K-5, without skipping shots. With these settings, it sounds like the next photo triggers almost immediately, I don't hear a 2 second pause between shots.

I tried that too. At first I thought it was working as I expected at the 31 and 32 interval but it was just the K-5 taking the DFS image.

Gimbal · 02-24-2012, 08:55 AM

Originally posted by Trig

I tried that too. At first I thought it was working as I expected at the 31 and 32 interval but it was just the K-5 taking the DFS image.

If that is the case I would say that you still haven't turned off DFS. If I set the interval to 32s It works, it does sound like it fires instantly after the previous shoot, and it does record a new image (it is not the DFS). 31sec though is to tight and it will skip every other shot.

Trig · 02-24-2012, 09:23 AM

Originally posted by Gimbal

If that is the case I would say that you still haven't turned off DFS. If I set the interval to 32s It works, it does sound like it fires instantly after the previous shoot, and it does record a new image (it is not the DFS). 31sec though is to tight and it will skip every other shot.

Interesting! I will double check and try it again and check back. I am certain that I did have the DFS off but I have been known to make mistakes before

02-23-2012, 11:33 AM	#1
Trig Senior Member Join Date: Aug 2009 Location: Acushnet, MA Photos: Gallery Posts: 211	Interval Shooting question(s) So I set up my trusty K-5 to do some interval shooting to capture some star trails. I am close to the city so I kind of have to go with interval shooting to help with the city lights flooding a long exposure shot. Here were my settings: Manual exposure at shutter speed of 30s Interval shooting set to: 00:00'31" (I set it to 31 seconds to give it 1 second to write to the card) Over 115 minutes of shooting, I got about 112 shots. This equates to about 1 exposure per minute. When I tried this at home to sit and watch the camera during this, it takes a shot over 30 seconds, then waits 30 seconds, then takes another shot. Yes, I read the recently posted article here of Pentax Forums. So, any clue what I could be doing wrong. The SD card is pretty darn fast and it sure doesn't look like it is stalling to write the image that could be throwing off the interval. Here is what the image looked like. You can clearly see the 30 second pause between exposures as evident of this really wide angle shot at 8mm. I assume that even with a second gap between exposures the "gap" would be seem as less at a wide angle such as this. Any suggestions out there?

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02-23-2012, 12:02 PM - 1 Like	#2
demp10 Veteran Member Join Date: Jun 2011 Location: Atlanta Photos: Albums Posts: 602	You are not doing anything wrong. When you take a long exposure, the camera does some processing to remove noise. Essentially it takes the same exposure with the shutter closed and then subtracts the "black" frame that has sensor noise only. That way the resulting image has significantly less noise. So for your 30sec exposure, there is a 30sec "correction".

02-23-2012, 12:05 PM	#3
Trig Senior Member Join Date: Aug 2009 Location: Acushnet, MA Photos: Gallery Posts: 211 Original Poster	Hmmmm...that is what I thought but I made sure I had that correction turned off on the camera. I normally do noise reduction in PP. Unless, it does the dark frame noise reduction when using interval timing and you cannot turn it off when using interval shooting?

02-23-2012, 12:18 PM	#4
Trig Senior Member Join Date: Aug 2009 Location: Acushnet, MA Photos: Gallery Posts: 211 Original Poster	Originally posted by demp10 You are not doing anything wrong. When you take a long exposure, the camera does some processing to remove noise. Essentially it takes the same exposure with the shutter closed and then subtracts the "black" frame that has sensor noise only. That way the resulting image has significantly less noise. So for your 30sec exposure, there is a 30sec "correction". You are correct. When shooting using interval shooting, it seems the dark frame reduction (noise reduction) cannot be shut off (even if you have it selected to be off). When I shoot at 25s, it works perfectly at a interval time of 26s. Thanks so much demp10!

02-23-2012, 02:00 PM	#5
ofer4 Veteran Member Join Date: Jun 2011 Location: Utah Posts: 428	Trig/demp10... I'm not sure that I follow this. Is this behavior specific to the K-5? I don't think I've seen it with my K-r. Also, Trig, is your last post saying that <30 sec exposures remove this behavior? Thanks!

02-23-2012, 02:47 PM	#6
demp10 Veteran Member Join Date: Jun 2011 Location: Atlanta Photos: Albums Posts: 602	The K-7 manual states that even if the Slow Shutter Speed NR is off, it will still operate in B mode and when the shutter speed is more than 30 sec.

02-23-2012, 04:50 PM	#7
Ex Finn. Site Supporter Join Date: Nov 2007 Location: Southern Maryland. Espoo. Kouvola. Photos: Gallery \| Albums Posts: 7,975	K5 is supposed to be a different animal as far as DFS. Even with the caps, that is a one cool shot.

02-23-2012, 05:53 PM	#8
imtheguy Site Supporter Join Date: Mar 2009 Location: Virginia Beach Photos: Gallery \| Albums Posts: 2,950	Just to make sure I understand this back and forth.....The k-5 WILL shoot in interval mode WITHOUT DFS (if its turned off in the menu) if the shutter speed is less than 30s? I just tested and know for sure it allows DFS to be off at 25s. Since only Bulb can exceed 30s I thought I missed the point here. Did I? Thanks folks.

02-23-2012, 06:14 PM	#9
Ex Finn. Site Supporter Join Date: Nov 2007 Location: Southern Maryland. Espoo. Kouvola. Photos: Gallery \| Albums Posts: 7,975	Didn`t one of the latest FW updates take care of the DF subtraction issues while shooting in bulb?. I never shoot star-trails so not much first hand help here.

02-23-2012, 06:40 PM	#10
Trig Senior Member Join Date: Aug 2009 Location: Acushnet, MA Photos: Gallery Posts: 211 Original Poster	Originally posted by demp10 The K-7 manual states that even if the Slow Shutter Speed NR is off, it will still operate in B mode and when the shutter speed is more than 30 sec. I am not shooting in bulb mode. I am shooting in Manual mode. If I take "continuos" shots of 30s, there is no delay as I see when shooting during interval at 30s exposures so it seems to me the DFS automatically gets turned on when shooting in interval. Originally posted by Ex Finn. K5 is supposed to be a different animal as far as DFS. Even with the caps, that is a one cool shot. I am certain I have the DFS turned off. Originally posted by imtheguy Just to make sure I understand this back and forth.....The k-5 WILL shoot in interval mode WITHOUT DFS (if its turned off in the menu) if the shutter speed is less than 30s? I just tested and know for sure it allows DFS to be off at 25s. Since only Bulb can exceed 30s I thought I missed the point here. Did I? Thanks folks. My K-5 shooting in Interval with DFS off up to 25s in manual mode. When I get to 30s exposures, the DFS automatically activates in Interval Shooting. I am not shooting in Blub for all this, just manual. Originally posted by Ex Finn. Didn`t one of the latest FW updates take care of the DF subtraction issues while shooting in bulb?. I never shoot star-trails so not much first hand help here. Yes, you can turn the DFS off and on, it just seems to come on (even with it selected to be off) when shooting in manual at a exposure of 30s. Thanks for all the input everyone. Sincerely appreciate it! At least all I need to do it set the exposure down to 25s and I should have very minimal gaps in the trails with a wide angel. Thanks!

02-23-2012, 11:09 PM	#11
walter Senior Member Join Date: Mar 2007 Location: California Photos: Gallery Posts: 239	Have you tried setting the interval to 32 seconds? That seems to work for my K-5, without skipping shots. With these settings, it sounds like the next photo triggers almost immediately, I don't hear a 2 second pause between shots.

02-24-2012, 06:17 AM	#12
Trig Senior Member Join Date: Aug 2009 Location: Acushnet, MA Photos: Gallery Posts: 211 Original Poster	Originally posted by walter Have you tried setting the interval to 32 seconds? That seems to work for my K-5, without skipping shots. With these settings, it sounds like the next photo triggers almost immediately, I don't hear a 2 second pause between shots. I tried that too. At first I thought it was working as I expected at the 31 and 32 interval but it was just the K-5 taking the DFS image.

02-24-2012, 08:55 AM	#13
Gimbal Pentaxian Join Date: Apr 2007 Location: Sweden Posts: 2,106	Originally posted by Trig I tried that too. At first I thought it was working as I expected at the 31 and 32 interval but it was just the K-5 taking the DFS image. If that is the case I would say that you still haven't turned off DFS. If I set the interval to 32s It works, it does sound like it fires instantly after the previous shoot, and it does record a new image (it is not the DFS). 31sec though is to tight and it will skip every other shot.

02-24-2012, 09:23 AM	#14
Trig Senior Member Join Date: Aug 2009 Location: Acushnet, MA Photos: Gallery Posts: 211 Original Poster	Originally posted by Gimbal If that is the case I would say that you still haven't turned off DFS. If I set the interval to 32s It works, it does sound like it fires instantly after the previous shoot, and it does record a new image (it is not the DFS). 31sec though is to tight and it will skip every other shot. Interesting! I will double check and try it again and check back. I am certain that I did have the DFS off but I have been known to make mistakes before