[Ray Somerfield]

Whoa. I'm glad I read this, I was seriously planning on getting the K7 based on the fact that dark frame subtraction could be turned off. If that's not the case, I don't see any reason to upgrade. It doesn't make sense. It would work just as well to manually take a few dark frames after you shoot a series of photos and apply them in post processing! This is incredibly disappointing

[Lowell Goudge]

Whoa. I'm glad I read this, I was seriously planning on getting the K7 based on the fact that dark frame subtraction could be turned off. If that's not the case, I don't see any reason to upgrade. It doesn't make sense. It would work just as well to manually take a few dark frames after you shoot a series of photos and apply them in post processing! This is incredibly disappointing

It might be worth posting a question to pentax, I don;t do much with Bulb mode so for me it is not an issue, but I did find it curious that it does not seem to be applied to Manual even with long exposures.

[Confused]

Hi Ray

I'm genuinely astonished to read your observation that:

I was seriously planning on getting the K7 based on the fact that dark frame subtraction could be turned off.

One of the main reasons why I initially decided not to upgrade from my current K10D's to the K20D was the infuriating limitation surrounding it's infamous dark-frame subtraction issue. To discover that the K7 is similarly blighted in this respect whilst employing Bulb mode almost beggars belief ! Have Pentax learned NOTHING whatsoever from their previous mistakes ? It's almost as if photographers are not to be trusted to think for themselves nowadays or make independent choices. Quite frankly, I find this sort of patronizing attitude from manufacturers incredibly irritating.
The automotive parallel to this type of idiocy is to be observed by the ever increasing appearance of so-called automatic "user-features" such as rain-sensing windscreen wipers or light-sensitive headlights on many new cars, the undeniable inference being that many of today's drivers are deemed either too lazy or stupid to use conventional controls. Maybe this is true, but thankfully I still have a few functioning grey cells left !

Best regards
Richard

[LeoTaylor]

You must have missed it. ...

I didn't miss it.

Oops, I'm a tad off topic because these were shot on July 8 at 1/250 sec and 2000mm.

The ISS is very bright, comparable to Venus in the morning. It is HARD to miss if you have the time right. Heavens-Above.com will guide you, just enter your latitude and longitude.

I do appreciate that my K110D can turn of NR when I want to take long astrophotos. I use my camera extensively almost every clear night but will never claim it is a good choice for astro. Oddly, I get better results using 2 minute exposures with in camera dark subtraction then subtracting dark frames afterward. Getting twice the throughput does not help if the target is lost in the noise. For 30 second exposures I do my own dark frames.

As soon as I read the Pentax CMOS cameras won't disable the dark subtraction I knew I would not upgrade. I'll stick with my 6 MP CCD cameras.

I've spoke with Pentax Reps at the NorthEast Astro Forum. Other then selling very good eyepieces they have no interest in promoting their cameras for astro. They seemed confused as to why I used one of their cameras in an observatory!

Attached Images

 

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Last edited by LeoTaylor; 07-13-2009 at 06:00 PM. Reason: added sentence

[Lowell Goudge]

I didn't miss it.

Oops, I'm a tad off topic because these were shot on July 8 at 1/250 sec and 2000mm.

The ISS is very bright, comparable to Venus in the morning. It is HARD to miss if you have the time right. Heavens-Above.com will guide you, just enter your latitude and longitude.

I do appreciate that my K110D can turn of NR when I want to take long astrophotos. I use my camera extensively almost every clear night but will never claim it is a good choice for astro. Oddly, I get better results using 2 minute exposures with in camera dark subtraction then subtracting dark frames afterward. Getting twice the throughput does not help if the target is lost in the noise. For 30 second exposures I do my own dark frames.

As soon as I read the Pentax CMOS cameras won't disable the dark subtraction I knew I would not upgrade. I'll stick with my 6 MP CCD cameras.

interesting, is this one image? does it go light and dark in the sky? if so, this might explain the blinking light that approximated a star trail in my shots.

Sorry for the image, shot with a 28-75, and some fool had to put a street light where I wanted to shoot I was hoping for a nice long sweeping arc, but I can't believe this is lens flair, in line perfectly with star trails.

[kittykat46]

....In the Bulb setting any time exposure will bring in ICNR wheather it is turned off or not.
.....

Yes, I missed that the first time.
I was using Manual with 20 secs shutter, NR turned off....and the DFS didn't kick in.
Tried the Bulb mode at 10 secs. last night.....DFS kicks in no matter what shutter time you use..

For what its worth, even with NR turned off, the noise is minimal at 20 secs on ISO 100 .
I haven't tried anything longer than 60 secs. yet.
1 minute at low ISO is still good, no avoiding the DFS, of course.

Doesn't seem to match what the manual says, Pg. 92

"NR Off Reduces noise only when the exposure mode is set to B and the
shutter remains open for 30 seconds or more."
(My emphasis)

Well, I'm keeping my K100D, partly for this reason...

Its a pity, because I love almost everything else about the K-7. Its like driving a sleek sports-car

[pentaxmz]

Hi Ray

I'm genuinely astonished to read your observation that:



One of the main reasons why I initially decided not to upgrade from my current K10D's to the K20D was the infuriating limitation surrounding it's infamous dark-frame subtraction issue. To discover that the K7 is similarly blighted in this respect whilst employing Bulb mode almost beggars belief ! Have Pentax learned NOTHING whatsoever from their previous mistakes ? It's almost as if photographers are not to be trusted to think for themselves nowadays or make independent choices. Quite frankly, I find this sort of patronizing attitude from manufacturers incredibly irritating.
The automotive parallel to this type of idiocy is to be observed by the ever increasing appearance of so-called automatic "user-features" such as rain-sensing windscreen wipers or light-sensitive headlights on many new cars, the undeniable inference being that many of today's drivers are deemed either too lazy or stupid to use conventional controls. Maybe this is true, but thankfully I still have a few functioning grey cells left !

Best regards
Richard

While I don't necessarily agree with your parallels , I do find it heartening that I am not alone with this significantly disappointing news.

My need to control DFS include and go beyond astrophotography. My work also requires long exposures.

Unfortunately, I suspect the reason why DFS is not controllable on the K7 are the same reasons why it isn't controllable on the K20D. If it is true that the K7 uses the same damn Samsung CMOS imager.... then don't ever expect a firmware update to fix this. The K20D's sensor runs hot and noisy and without the DFS, the images would be unacceptable.

I will go further to speculate that the K7 is simply a redressed K20D with a few extra bells and whistles.

I realize the major crime I have committed by making the above statement and I'll fully repent if I am wrong... actually I hope I am wrong! Please, someone tell me this is a nightmare and I will wake up and find that all is good with the K7. All I wish for is the ability to turn off DFS! Is that too much to ask for from Pentax?

For all those who care, please inundate Pentax with enquires about this issue! And please post the replies you receive back from Pentax.

[pentaxmz]

I didn't miss it.

Oops, I'm a tad off topic because these were shot on July 8 at 1/250 sec and 2000mm.

The ISS is very bright, comparable to Venus in the morning. It is HARD to miss if you have the time right. Heavens-Above.com will guide you, just enter your latitude and longitude.

I do appreciate that my K110D can turn of NR when I want to take long astrophotos. I use my camera extensively almost every clear night but will never claim it is a good choice for astro. Oddly, I get better results using 2 minute exposures with in camera dark subtraction then subtracting dark frames afterward. Getting twice the throughput does not help if the target is lost in the noise. For 30 second exposures I do my own dark frames.

As soon as I read the Pentax CMOS cameras won't disable the dark subtraction I knew I would not upgrade. I'll stick with my 6 MP CCD cameras.

I've spoke with Pentax Reps at the NorthEast Astro Forum. Other then selling very good eyepieces they have no interest in promoting their cameras for astro. They seemed confused as to why I used one of their cameras in an observatory!

Ah, now there you have it. I had several similar responses from Pentax when I dared to BOTHER them about this issue on the K20D.

The cultural difference between Pentax and Canon (and even Nikon) is markedly different! Canon (and I think Nikon) actually have hobbyist divisions that are actually operated by astronomers and their job is to provide support to the astronomy/scientific community. It is very clear that Pentax has ZERO interest in such a small community.

The emails I received back offered no further support, no telephone number, not even a email signature. And yes, I was very polite in all my emails.
The email address used was: photo_end_US@pentax.com and the names were: Dorian B, Rob S., Michele R. - I suspect these are fake names.

Does Pentax even care? I have heard a number of times how Pentax support sucks compared to the big two.

[nostatic]

You can't please all of the people all of the time. If there are only a handful of users on this forum for whom this is an issue, do you really think that Pentax would devote engineering dollars to solving this? My guess is that in fact this is a hardware limitation and there isn't an easy way around it.

Pentax has made it clear that they are going after a niche of small/tough/weatherproof. They will focus their engineering efforts there. They do not have the size of Canikon to chase every market. So if this really is a make or break issue, then you should buy another camera. No histrionics or rants really needed. Tilting at windmills gets tiring.

Everyone makes compromises with their camera. It is up to the individual to decide where the lines are drawn. It is not reasonable to expect the manufacturer to address everyone's issues.

[pentaxmz]

interesting, is this one image? does it go light and dark in the sky? if so, this might explain the blinking light that approximated a star trail in my shots.

Sorry for the image, shot with a 28-75, and some fool had to put a street light where I wanted to shoot I was hoping for a nice long sweeping arc, but I can't believe this is lens flair, in line perfectly with star trails.

Definitely lens flair, sorry .... but you do have star trails (about a 5 min. exposure?).

ISS is unmistakable when it crosses over. Generally it is fast, usually much less than 2 minutes to cross the visible sky (or until it enters Earth's shadow). And it is usually as bright as Venus and appears sharp like a 'moving star'. The object you 'captured' is quite diffuse and can only be lens flair.

For schedules of ISS and other objects over your sky, check out this page: Human Space Flight (HSF) - Realtime Data

[pentaxmz]

You can't please all of the people all of the time. If there are only a handful of users on this forum for whom this is an issue, do you really think that Pentax would devote engineering dollars to solving this? My guess is that in fact this is a hardware limitation and there isn't an easy way around it.

Your attitude toward this issue is astounding and you completely miss the big picture.

This is not about some small group of astronomers!

It is about a real and fundamental problem that only affects some Pentax cameras. It's this sort of problem that a reputation emerges that Pentax products are flawed. Whether is a difficult problem to fix or not is irrelevant, what is relevant is that the other DSLRs don't have this problem.

Pentax has made it clear that they are going after a niche of small/tough/weatherproof. They will focus their engineering efforts there. They do not have the size of Canikon to chase every market. So if this really is a make or break issue, then you should buy another camera.

As I have previously stated, this NOT about astronomy. It is about a basic camera functionality that one should expect as a bare minimum. You will not find this problem on any other non-Pentax DSLR.

Currently the Pentax K20D (and possibly the K7) is not convenient to use for anything where your bulb exposures are measured in the minutes, such as:

- city night life (vehicle light trails)
- night time lightning storms (you're going to miss a lot waiting for DFS)
- astronomy (that's a given)
- artistic long exposure work
- high speed strobe photography (i.e. such as Edgerton's work where a high speed strobe is trigger by some form a sensor - the camera needs to be open in bulb mode for this)
- etc.

There is nothing weird or unusual about the above types of photography. Heck, I was doing all the above in high school on Pentax K1000's!

I'm not claiming the K20D can't be used....but trust me, after the amount of time you will spend waiting for the completely unnecessary DFS to finish, you will wish you had a different camera!

[Lowell Goudge]

While I don't necessarily agree with your parallels , I do find it heartening that I am not alone with this significantly disappointing news.

My need to control DFS include and go beyond astrophotography. My work also requires long exposures.

Unfortunately, I suspect the reason why DFS is not controllable on the K7 are the same reasons why it isn't controllable on the K20D. If it is true that the K7 uses the same damn Samsung CMOS imager.... then don't ever expect a firmware update to fix this. The K20D's sensor runs hot and noisy and without the DFS, the images would be unacceptable.

I will go further to speculate that the K7 is simply a redressed K20D with a few extra bells and whistles.

I realize the major crime I have committed by making the above statement and I'll fully repent if I am wrong... actually I hope I am wrong! Please, someone tell me this is a nightmare and I will wake up and find that all is good with the K7. All I wish for is the ability to turn off DFS! Is that too much to ask for from Pentax?

For all those who care, please inundate Pentax with enquires about this issue! And please post the replies you receive back from Pentax.

yes indeed quitre a crime, since the K7 is reported to have a new sensor, optimized for video, which to me implies better thermal management.

[Lowell Goudge]

Definitely lens flair, sorry .... but you do have star trails (about a 5 min. exposure?).

ISS is unmistakable when it crosses over. Generally it is fast, usually much less than 2 minutes to cross the visible sky (or until it enters Earth's shadow). And it is usually as bright as Venus and appears sharp like a 'moving star'. The object you 'captured' is quite diffuse and can only be lens flair.

For schedules of ISS and other objects over your sky, check out this page: Human Space Flight (HSF) - Realtime Data

actually 6 minutes and change, the scheduled time from the internet should have had the station trace a nice arc, it reported rising in the wsw sky and setting in the nw sky with a 50 degree maximum height. never saw a thing

thsnks for the link but that's where my data came from. still dont know what went wrong on that front..

[pentaxmz]

actually 6 minutes and change, the scheduled time from the internet should have had the station trace a nice arc, it reported rising in the wsw sky and setting in the nw sky with a 50 degree maximum height. never saw a thing

thsnks for the link but that's where my data came from. still dont know what went wrong on that front..

I am going to prepare four days of print outs (for ISS and other stuff) before my trip to Pacific Rim National Park. It's going to be amazing being under such dark skies. I haven't experienced anything like this in over ten years. The World Atlas of the Artificial Night Sky Brightness

[nostatic]

I'm not claiming the K20D can't be used....but trust me, after the amount of time you will spend waiting for the completely unnecessary DFS to finish, you will wish you had a different camera!

Then buy a different camera.

The vast majority of users find this a non-issue and Pentax has chosen not to address it. If it is that important you should move along and stop trying to tell Pentax how to design their cameras. Hint - they apparently don't care. When I find a company that doesn't care I do business with another one. And I don't necessarily feel it is my place to repeatedly announce to the world how right I am and how wrong they are.