The K7 and long exposures

ambienthousewife · 11-16-2009, 06:13 AM

Originally posted by simico

Without the (forced) DFS, you would be very annoyed by the high amount of noise.

Actually, having seen 30 minute exposures from a D90 without DFS or any noise reduction, I am not sure I would.

simico · 11-17-2009, 05:48 AM

Originally posted by ambienthousewife

Actually, having seen 30 minute exposures from a D90 without DFS or any noise reduction, I am not sure I would.

Nice try. D90 makes DFS for exposures longer than 8 sec.

ambienthousewife · 11-17-2009, 10:29 AM

Originally posted by simico

Nice try. D90 makes DFS for exposures longer than 8 sec.

But you can turn it off on other camera systems. And it provides a useful improvement in the usability of the camera for sequences of exposures. Heck, I can turn it off on my K100, I know it is awful after a couple of minutes (after all, the K100 is pretty old now), but I would like the option with my next Pentax upgrade. It *is* possible, which is why previous posters in this thread (who I presume have also come across it) were asking for it to be added as an option in firmware for the K7.

pentaxmz · 11-17-2009, 05:30 PM

Originally posted by ambienthousewife

But you can turn it off on other camera systems. And it provides a useful improvement in the usability of the camera for sequences of exposures. Heck, I can turn it off on my K100, I know it is awful after a couple of minutes (after all, the K100 is pretty old now), but I would like the option with my next Pentax upgrade. It *is* possible, which is why previous posters in this thread (who I presume have also come across it) were asking for it to be added as an option in firmware for the K7.

Forget trying to explain this logically. There are folks in this forum who believe if it doesn't affect them, the problem is non-existent.

The inability to shut off auto-DFS on both the K20D and the K7 is a joke, and a cover up of the serious inadequacies of the sensor and firmware in these cameras. Little to no improvements were made in regards to this on either camera.

In the same class or better, all other DSLR manufacturers are light years ahead of Pentax for low light, longer exposure photography. Don't believe me? Go try out a Canon 30D or better, you might be shocked into reality.

Hey, before you flame me...

just remember that this is one of my very few issues with Pentax. Most everything else with my K20D is near excellent!

simico · 11-18-2009, 02:28 AM

Originally posted by ambienthousewife

Heck, I can turn it off on my K100,

Your K100 has a CCD sensor, not CMOS. You can disable DFS on all Pentax DSLRs havong a CCD sensor. K20D, K-7 and K-x has CMOS sensor. CMOS sensors have higher circuitry thermal noise than CCD sensors.

Demanding things from Pentax and making bold statements with zero technical knowledge is laughable.

**Ash** · 11-18-2009, 12:32 PM

I hear you PentaxMZ.

I've found it frustrating that exposures longer than even 15 secs at low ISO on my K20D produce noticeable and image-deteriorating noise.

I expected the opposite given the CMOS sensor hype when it was coming out - low heat generated by the more energy-efficient sensor means less noise. I believed that with would be translated to low long-exposure noise. Obviously not so.

I'm at least fortunate that I kept my K10D, which performs remarkably well in long exposures. But I do believe it's an indictment on Pentax's sensor technology that long exposures are no longer an acceptable on the newer, supposedly better sensors and begs the question - why bother with CMOS at all, when it's obvious the CCD sensors (like in the K-x) can be made with high quality, almost at the same resolution, and manage with low noise in all circumstances...

I too would wish Pentax got their act together on this issue, particularly for their flagship models, but would have to concede that it's unlikely Pentax would do anything about it at this stage for their CMOS cameras.

**Ex Finn.** · 11-18-2009, 03:54 PM

Forced DFS was a deal killer for me, had 2k saved up for K7, grip and some other things.
Went to best buy and came home with 52" bravia. I will have to wait and see what happens with the next model.

Cheers, Mike.

pentaxmz · 11-20-2009, 05:01 AM

Originally posted by simico

Your K100 has a CCD sensor, not CMOS. You can disable DFS on all Pentax DSLRs havong a CCD sensor. K20D, K-7 and K-x has CMOS sensor. CMOS sensors have higher circuitry thermal noise than CCD sensors.

Demanding things from Pentax and making bold statements with zero technical knowledge is laughable.

Making comments with limited knowledge is also laughable. Sorry, I couldn't resist.

Yes, it is a well known fact that thermal noise is a problem in all sensors, and especially CMOS sensors. Great, you got that right... quick look up on Wikipedia.

But you obviously forgot that many other cameras (such as the hugely successful Canon xxD series) also employ CMOS imagers, and take low noise long exposures WITHOUT forced DFS. Why? Because their sensors have better thermal dissipation, better designed overall, and a better/faster imaging computer.

slowdive101 · 11-20-2009, 02:15 PM

I emailed Pentax to let them know how unimpressed I was with the forced DFS. Here's the response:
-----
Hello:

At preseent you cannot turn off the DFS on exposures over 30 sec.

We will be sending an email to Japan requesting they add this ability to their next firmware update.

Best Regards

CSR2
The Pentax CSR Team
-----

Who knows if it'll happen, but at least the reply seems to be an acknowledgement that forced DFS is a problem.

simico · 11-25-2009, 02:39 AM

Originally posted by pentaxmz

Why? Because their sensors have better thermal dissipation, better designed overall, and a better/faster imaging computer.

Great, you've just got back to the point of my first post in this thread: without the forced DFS in K20/K7 you would complain about the noise, because the Samsung sensor doesn't shine when it comes to noise. It's irrelevant that other systems allows you to disable DFS - they don't use the same sensor as K20 and K7.

By the way, long exposures without DFS or noise reduction ain't look that great on canikon either...

pentaxmz · 11-26-2009, 04:51 PM

Originally posted by slowdive101

I emailed Pentax to let them know how unimpressed I was with the forced DFS. Here's the response:
-----
Hello:

At preseent you cannot turn off the DFS on exposures over 30 sec.

We will be sending an email to Japan requesting they add this ability to their next firmware update.

Best Regards

CSR2
The Pentax CSR Team
-----

Who knows if it'll happen, but at least the reply seems to be an acknowledgement that forced DFS is a problem.

Not a chance! Don't hold your breath. I received a similar (almost exact) reply about two years ago (in regards to DFS on K20D).

pentaxmz · 11-26-2009, 05:03 PM

Originally posted by simico

Great, you've just got back to the point of my first post in this thread: without the forced DFS in K20/K7 you would complain about the noise, because the Samsung sensor doesn't shine when it comes to noise. It's irrelevant that other systems allows you to disable DFS - they don't use the same sensor as K20 and K7.

No, you got this all wrong.

The point is that I (we) want to control DFS OFF CAMERA. I already know and expect noise and it won't be nearly as bad as the thermal noise in cameras I used years ago.

Originally posted by simico

By the way, long exposures without DFS or noise reduction ain't look that great on canikon either...

Since you used that term canikon.... and your blanket erroneous statement, I can only surmise that you have no experience with canikon. With all due respect some of the Canon cameras are 'light years' ahead of Pentax's best camera. I have no DSLR experience with Nikon so I will reserve further comment.

Nass · 12-17-2009, 08:53 AM

FWIW, I just lodged this same request with Pentax.

It's a real shame. And those guys telling us it's a non-issue can go piss up a rope as far as I'm concerned. When you spend $2k on a body and some lenses you expect those sort of options.

Originally posted by falconeye

Can somebody please do the following experiment:

1. one long exposure at 4:30 min (ISO 1600) in bulb mode
2. a multi exposure, 9 images, auto-EV compensation, 30s each, no bulb mode(consecutive exposures using a remote).

And provide the two respective RAW files.

I am really curious to see how much impact DFS (the only difference between #1 and #2) really has.

Maybe, if the impact is marginal, we can convince Pentax to make DFS optional for at least up to 5 minutes.

Falk did anyone ever do this for you? Need me to do it?

fisheye freak · 12-19-2009, 12:28 AM

My K10d drives me nuts with its automatic dark subtraction.It is a problem with all digital cameras.Top end astrophotography cameras are supercooled to minimise the hot pixels and dark subtraction frames are still often used, although it is possible to cheat and have them saved to reuse again, as long as they are appropriate for the temperature conditions. The astrophotography guys need as much time to gather photons as they can.Some of the astro rigs go for $60,000 plus. Raw image capture for one shot often takes months , requiring driving for hours to a dark sky site, aligning exactly for the celestial pole, keeping aligned (there are guiding programs to help, reqiuring a second telescope mounted to the rig to follow the guide star), hoping the clouds, wind or turbulence do not affect the capture, cursing dew on the telescope mirror/corrector plate/front element. The astro stuff makes conventional photography look easy.

Gimbal · 12-19-2009, 04:47 AM

Originally posted by fisheye freak

My K10d drives me nuts with its automatic dark subtraction.It is a problem with all digital cameras.

Well, shut it off then. On the k10d you have the option.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Nature Long exposures at the beach	ismaelg	Post Your Photos!	8	04-20-2010 10:39 PM
Cityscape Long Exposures	attack11	Post Your Photos!	6	01-20-2010 01:49 PM
K20d - long exposures	Luke_	Pentax DSLR Discussion	5	07-28-2009 05:30 AM
Long Exposures Dancing	metroeloise	Post Your Photos!	3	01-07-2009 04:35 PM
Long exposures.	blwnhr	Post Your Photos!	12	08-05-2008 03:36 AM

11-16-2009, 06:13 AM	#121
ambienthousewife Junior Member Join Date: Jan 2008 Location: West Sussex, UK Photos: Gallery Posts: 38	Originally posted by simico Without the (forced) DFS, you would be very annoyed by the high amount of noise. Actually, having seen 30 minute exposures from a D90 without DFS or any noise reduction, I am not sure I would.

11-17-2009, 05:48 AM	#122
simico Veteran Member Join Date: Jan 2009 Location: Budapest Posts: 821	Originally posted by ambienthousewife Actually, having seen 30 minute exposures from a D90 without DFS or any noise reduction, I am not sure I would. Nice try. D90 makes DFS for exposures longer than 8 sec.

11-17-2009, 10:29 AM	#123
ambienthousewife Junior Member Join Date: Jan 2008 Location: West Sussex, UK Photos: Gallery Posts: 38	Originally posted by simico Nice try. D90 makes DFS for exposures longer than 8 sec. But you can turn it off on other camera systems. And it provides a useful improvement in the usability of the camera for sequences of exposures. Heck, I can turn it off on my K100, I know it is awful after a couple of minutes (after all, the K100 is pretty old now), but I would like the option with my next Pentax upgrade. It is possible, which is why previous posters in this thread (who I presume have also come across it) were asking for it to be added as an option in firmware for the K7.

11-17-2009, 05:30 PM	#124
pentaxmz Veteran Member Join Date: Dec 2008 Location: Seattle Posts: 659 Original Poster	Originally posted by ambienthousewife But you can turn it off on other camera systems. And it provides a useful improvement in the usability of the camera for sequences of exposures. Heck, I can turn it off on my K100, I know it is awful after a couple of minutes (after all, the K100 is pretty old now), but I would like the option with my next Pentax upgrade. It is possible, which is why previous posters in this thread (who I presume have also come across it) were asking for it to be added as an option in firmware for the K7. Forget trying to explain this logically. There are folks in this forum who believe if it doesn't affect them, the problem is non-existent. The inability to shut off auto-DFS on both the K20D and the K7 is a joke, and a cover up of the serious inadequacies of the sensor and firmware in these cameras. Little to no improvements were made in regards to this on either camera. In the same class or better, all other DSLR manufacturers are light years ahead of Pentax for low light, longer exposure photography. Don't believe me? Go try out a Canon 30D or better, you might be shocked into reality. Hey, before you flame me... just remember that this is one of my very few issues with Pentax. Most everything else with my K20D is near excellent!

11-18-2009, 02:28 AM	#125
simico Veteran Member Join Date: Jan 2009 Location: Budapest Posts: 821	Originally posted by ambienthousewife Heck, I can turn it off on my K100, Your K100 has a CCD sensor, not CMOS. You can disable DFS on all Pentax DSLRs havong a CCD sensor. K20D, K-7 and K-x has CMOS sensor. CMOS sensors have higher circuitry thermal noise than CCD sensors. Demanding things from Pentax and making bold statements with zero technical knowledge is laughable.

11-18-2009, 12:32 PM	#126
Ash Loyal Site Supporter Join Date: Mar 2007 Location: Toowoomba, Queensland Photos: Gallery \| Albums Posts: 23,920	I hear you PentaxMZ. I've found it frustrating that exposures longer than even 15 secs at low ISO on my K20D produce noticeable and image-deteriorating noise. I expected the opposite given the CMOS sensor hype when it was coming out - low heat generated by the more energy-efficient sensor means less noise. I believed that with would be translated to low long-exposure noise. Obviously not so. I'm at least fortunate that I kept my K10D, which performs remarkably well in long exposures. But I do believe it's an indictment on Pentax's sensor technology that long exposures are no longer an acceptable on the newer, supposedly better sensors and begs the question - why bother with CMOS at all, when it's obvious the CCD sensors (like in the K-x) can be made with high quality, almost at the same resolution, and manage with low noise in all circumstances... I too would wish Pentax got their act together on this issue, particularly for their flagship models, but would have to concede that it's unlikely Pentax would do anything about it at this stage for their CMOS cameras.

11-18-2009, 03:54 PM	#127
Ex Finn. Site Supporter Join Date: Nov 2007 Location: Southern Maryland. Espoo. Kouvola. Photos: Gallery \| Albums Posts: 7,975	Forced DFS was a deal killer for me, had 2k saved up for K7, grip and some other things. Went to best buy and came home with 52" bravia. I will have to wait and see what happens with the next model. Cheers, Mike.

11-20-2009, 05:01 AM	#128
pentaxmz Veteran Member Join Date: Dec 2008 Location: Seattle Posts: 659 Original Poster	Originally posted by simico Your K100 has a CCD sensor, not CMOS. You can disable DFS on all Pentax DSLRs havong a CCD sensor. K20D, K-7 and K-x has CMOS sensor. CMOS sensors have higher circuitry thermal noise than CCD sensors. Demanding things from Pentax and making bold statements with zero technical knowledge is laughable. Making comments with limited knowledge is also laughable. Sorry, I couldn't resist. Yes, it is a well known fact that thermal noise is a problem in all sensors, and especially CMOS sensors. Great, you got that right... quick look up on Wikipedia. But you obviously forgot that many other cameras (such as the hugely successful Canon xxD series) also employ CMOS imagers, and take low noise long exposures WITHOUT forced DFS. Why? Because their sensors have better thermal dissipation, better designed overall, and a better/faster imaging computer.

11-20-2009, 02:15 PM	#129
slowdive101 Junior Member Join Date: Nov 2009 Location: winnipeg, mb Photos: Albums Posts: 48	I emailed Pentax to let them know how unimpressed I was with the forced DFS. Here's the response: ----- Hello: At preseent you cannot turn off the DFS on exposures over 30 sec. We will be sending an email to Japan requesting they add this ability to their next firmware update. Best Regards CSR2 The Pentax CSR Team ----- Who knows if it'll happen, but at least the reply seems to be an acknowledgement that forced DFS is a problem.

11-25-2009, 02:39 AM	#130
simico Veteran Member Join Date: Jan 2009 Location: Budapest Posts: 821	Originally posted by pentaxmz Why? Because their sensors have better thermal dissipation, better designed overall, and a better/faster imaging computer. Great, you've just got back to the point of my first post in this thread: without the forced DFS in K20/K7 you would complain about the noise, because the Samsung sensor doesn't shine when it comes to noise. It's irrelevant that other systems allows you to disable DFS - they don't use the same sensor as K20 and K7. By the way, long exposures without DFS or noise reduction ain't look that great on canikon either...

11-26-2009, 04:51 PM	#131
pentaxmz Veteran Member Join Date: Dec 2008 Location: Seattle Posts: 659 Original Poster	Originally posted by slowdive101 I emailed Pentax to let them know how unimpressed I was with the forced DFS. Here's the response: ----- Hello: At preseent you cannot turn off the DFS on exposures over 30 sec. We will be sending an email to Japan requesting they add this ability to their next firmware update. Best Regards CSR2 The Pentax CSR Team ----- Who knows if it'll happen, but at least the reply seems to be an acknowledgement that forced DFS is a problem. Not a chance! Don't hold your breath. I received a similar (almost exact) reply about two years ago (in regards to DFS on K20D).

11-26-2009, 05:03 PM	#132
pentaxmz Veteran Member Join Date: Dec 2008 Location: Seattle Posts: 659 Original Poster	Originally posted by simico Great, you've just got back to the point of my first post in this thread: without the forced DFS in K20/K7 you would complain about the noise, because the Samsung sensor doesn't shine when it comes to noise. It's irrelevant that other systems allows you to disable DFS - they don't use the same sensor as K20 and K7. No, you got this all wrong. The point is that I (we) want to control DFS OFF CAMERA. I already know and expect noise and it won't be nearly as bad as the thermal noise in cameras I used years ago. Originally posted by simico By the way, long exposures without DFS or noise reduction ain't look that great on canikon either... Since you used that term canikon.... and your blanket erroneous statement, I can only surmise that you have no experience with canikon. With all due respect some of the Canon cameras are 'light years' ahead of Pentax's best camera. I have no DSLR experience with Nikon so I will reserve further comment.

12-17-2009, 08:53 AM	#133
Nass Veteran Member Join Date: Aug 2009 Location: The British Isles Photos: Gallery Posts: 2,402	FWIW, I just lodged this same request with Pentax. It's a real shame. And those guys telling us it's a non-issue can go piss up a rope as far as I'm concerned. When you spend $2k on a body and some lenses you expect those sort of options. Originally posted by falconeye Can somebody please do the following experiment: 1. one long exposure at 4:30 min (ISO 1600) in bulb mode 2. a multi exposure, 9 images, auto-EV compensation, 30s each, no bulb mode(consecutive exposures using a remote). And provide the two respective RAW files. I am really curious to see how much impact DFS (the only difference between #1 and #2) really has. Maybe, if the impact is marginal, we can convince Pentax to make DFS optional for at least up to 5 minutes. Falk did anyone ever do this for you? Need me to do it?

12-19-2009, 12:28 AM	#134
fisheye freak Senior Member Join Date: Jan 2008 Location: Bondi, Australia Posts: 206	My K10d drives me nuts with its automatic dark subtraction.It is a problem with all digital cameras.Top end astrophotography cameras are supercooled to minimise the hot pixels and dark subtraction frames are still often used, although it is possible to cheat and have them saved to reuse again, as long as they are appropriate for the temperature conditions. The astrophotography guys need as much time to gather photons as they can.Some of the astro rigs go for $60,000 plus. Raw image capture for one shot often takes months , requiring driving for hours to a dark sky site, aligning exactly for the celestial pole, keeping aligned (there are guiding programs to help, reqiuring a second telescope mounted to the rig to follow the guide star), hoping the clouds, wind or turbulence do not affect the capture, cursing dew on the telescope mirror/corrector plate/front element. The astro stuff makes conventional photography look easy.

12-19-2009, 04:47 AM	#135
Gimbal Pentaxian Join Date: Apr 2007 Location: Sweden Posts: 2,106	Originally posted by fisheye freak My K10d drives me nuts with its automatic dark subtraction.It is a problem with all digital cameras. Well, shut it off then. On the k10d you have the option.