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09-21-2010, 08:39 AM   #1
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K5: DFS can be switched off?

One user on a German forum, who was at the Photokina today, saw it in the menu and could turn it off, he tested it in Bulb.
He wrote it has Auto, OFF and ON.
Kr has only OFF and ON.

09-21-2010, 05:36 PM   #2
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I believe the K-7 has the same options, but "off" is overridden in bulb mode in exposures longer than 30 seconds. I hope off really means off this time. Come on Pentax.
09-21-2010, 05:51 PM   #3
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QuoteOriginally posted by blende8 Quote
One user on a German forum, who was at the Photokina today, saw it in the menu and could turn it off, he tested it in Bulb.
He wrote it has Auto, OFF and ON.
Kr has only OFF and ON.
What is DFS? just curious!
09-21-2010, 06:00 PM   #4
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Dark Frame Subtraction, for noise reduction.
See Dark frame subtraction - Wikipedia, the free encyclopedia

DFS is incredibly annoying on long exposures because for every second of exposure there is another one added where the camera is busy working on DFS. I turn it off in my K10D and do noise reduction in post-processing... because when I'm taking a 5-7 minute exposure, I don't want to stand around for another 5-7 minutes after the shot until the camera is available again.

People also turn it off when they want to stack multiple shots of star trails together to get a continuous rotation of the stars in the sky. You need DFS off to eliminate gaps between consecutive shots.

I will upgrade from the K10D to the K5 in a few months, once the price starts coming down. The K5 is a huge advance over the K10D and I expect it will be a real pleasure to use. But I really really hope DFS can be turned off. It seems to me that is something that could be accomplished with some firmware programming.


Last edited by bats; 09-21-2010 at 06:11 PM.
09-21-2010, 07:49 PM   #5
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Saw this quote on Falk Lumo's blog:
QuoteQuote:
Hello

I dont want to create a new pentaxforums account.

I have been on PK today and it looks like DFS can be disabled completly, you have the "Auto, Yes, No" Modus (non final Firmware)

I switched it of and used bulb for more then 30seconds, next picture in <1sec

I talked to a staff member who confirmed that thethering will be delivered later by firmware (final or later)
Check the comments on his first impressions post. Falk Lumo
09-21-2010, 09:51 PM   #6
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Thanks, Jeff. I hope this turns out to be true. I'm aching to upgrade to the K5 :-)
09-21-2010, 11:17 PM   #7
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I hope it's true, but until someone takes a one minute exposure without DFS I remain skeptical.

Edit: didn't see the comment on Lumos blogg until now, sounds good so far. Maybe....
09-22-2010, 12:26 AM   #8
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K20D, why I don't see anything name DFS but Slow Shutter Speed NR and it only has Auto & On. There is no way it have Off.

I have one time get trouble with slow shutter, I set 30s shutter speed and after a shot, I have to wait 30s before the K20D can have a next shot. Is that DFS effect?

09-22-2010, 12:36 AM   #9
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QuoteOriginally posted by Gimbal Quote
I hope it's true, but until someone takes a one minute exposure without DFS I remain skeptical.

Edit: didn't see the comment on Lumos blogg until now, sounds good so far. Maybe....
On Sunday, I'm going to try myself if I can get to the Pentax stand early enough to hold the K-5 long enough...

But... same as add features through firmware upgrade, the final firmware may also remove certain things if they are considered not mature enough. Only the final firmware will tell...

Wim
09-22-2010, 01:26 AM   #10
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QuoteOriginally posted by Terzof Quote
I have one time get trouble with slow shutter, I set 30s shutter speed and after a shot, I have to wait 30s before the K20D can have a next shot. Is that DFS effect?
Yes.
It cannot be turned off on the K20 and K7.
09-22-2010, 02:39 AM   #11
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Well if, despite initial reports that it couldn't, if it CAN be turned off, then I take back everything I whined about
09-23-2010, 09:57 AM   #12
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QuoteOriginally posted by Terzof Quote
K20D, why I don't see anything name DFS but Slow Shutter Speed NR and it only has Auto & On. There is no way it have Off.

I have one time get trouble with slow shutter, I set 30s shutter speed and after a shot, I have to wait 30s before the K20D can have a next shot. Is that DFS effect?
Yes. Slow Shutter Speed NR is what Pentax calls their implementation of automatic dark frame subtraction.

The idea is that some aspects of sensor noise in a long exposure are fixed and nonrandom for a given sensor at a given temperature and exposure time. So you can remove this noise by taking a "dark frame" sample and subtracting it.

The problem with the K20D and K-7 is that this is forced for bulb exposures greater than 30 seconds and non-bulb exposures longer than somewhere around 2-4 seconds. This is massively annoying to fireworks photographers (If I'm happy with the noise levels at 25 seconds, do you really think I'll be unhappy at 35?), and to people doing nighttime panorama work. (Dark frame noise, as stated before, is a mostly fixed function of temperature and exposure time. So if you have a "warmed up" sensor at thermal equilibrium, you only need to take one dark frame before taking the constituent individual photos of a panorama. Pentax forces you to take a dark frame for each constituent photo in the K20D and K-7.
09-23-2010, 10:11 AM   #13
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I'm pretty sure I had Slow Shutter Speed NR OFF on my K-7 and did a bulb less than 30 seconds and it still did a DFS.
09-23-2010, 10:48 AM   #14
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As far as i know the DFS is called" noise reduktion on long exposures"(maybe wrong translation from my german menu)

I switched it off on Photokina and (as i already said) and used "Bulb" for more then 30 secs, the next picture was taken <1sec later...

So it seems that DFS in Firmware 0.1 can be switched off.
09-23-2010, 11:04 AM   #15
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QuoteOriginally posted by Mehlsack Quote
As far as i know the DFS is called" noise reduktion on long exposures"(maybe wrong translation from my german menu)

I switched it off on Photokina and (as i already said) and used "Bulb" for more then 30 secs, the next picture was taken <1sec later...

So it seems that DFS in Firmware 0.1 can be switched off.
That's fantastic
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