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11-20-2009, 05:05 AM   #1
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LOL, I'm loving my Pentax K7 coz its WIERD! :D

Hey everybody, newbie poster here! My first post, and I'm already raving about my brand new Pentax K7, an upgrade from my well-loved K110D. During the past few weeks, I did so much research into K7 that it now feels almost like I've long had it.

But what really gets me is the weirdness... What's the deal with all these hot pixels in "long exposures" already? I spent the best part of last evening and this morning conducting tests, comparing with K110D, updating firmware (to 1.01 and then 1.02), reading this and other forums... and instead of solutions arrived at a new relationship with the beast: "Pentax problems are not to be solved, they are to be loved"!

Try this: update your K7 firmware to 1.02, turn OFF noise reduction on long exposures, then do two shots at high ISO, say 1600, both for 10s, but one on Manual, the other on Bulb. If things work on your camera as they do on mine, what you will get is hot pixels on the Manual shot, but no hot pixels on the Bulb shot, even though there was no noise reduction going on after the Bulb exposure!

Unreal! And enough for me to forget the whole problem, since I discovered that my aged old version of ACR does indeed fight the little pixies very efficiently anyway.

Here's looking forward to the next firmware update and more loveable weirdness!

Long live Petax and all Pentaxonians!

11-20-2009, 11:01 AM   #2
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Bulb - Dark frame subtraction
manual - no Dark frame subtraction
11-20-2009, 11:08 AM   #3
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Yep, manual you can do no DFS for up to 30s.

On CCD cameras you can disable DFS totally. Advantage is if you take a lot of nighttime photos, you can just do Dark Frames at the end of the night instead of waiting inbetween each shot.
11-20-2009, 11:10 AM   #4
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I tried, you re right some 10 hot pixels in M mode comparerd to none Bulb. But, I think eigelb has the point.

11-20-2009, 12:15 PM   #5
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Friends, you seem unfazed, and that's a good thing. But where is the logic? Why must I count the seconds, holding a wire release, to obtain the benefit of DFS in camera? When I bought it, I expected I was paying for satisfying convenience, not arbitrary paradoxes.

Still, I can't hardly keep my hands off the little beauty! And it helps to know my peers love theirs too. But if anyone from Pentax reads this - give me DFS in Manual, I believe I paid for it already.
11-20-2009, 12:27 PM   #6
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Sorry if this is a n00b question, but what is "Dark Frame Subtraction" and why is it considered a bad thing?
11-20-2009, 01:11 PM   #7
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QuoteOriginally posted by jacksonpritt Quote
Sorry if this is a n00b question, but what is "Dark Frame Subtraction" and why is it considered a bad thing?
https://www.pentaxforums.com/forums/817656-post3.html
11-20-2009, 01:20 PM   #8
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QuoteOriginally posted by pentup007 Quote
Hey everybody, newbie poster here! My first post, and I'm already raving about my brand new Pentax K7, an upgrade from my well-loved K110D. During the past few weeks, I did so much research into K7 that it now feels almost like I've long had it.

But what really gets me is the weirdness... What's the deal with all these hot pixels in "long exposures" already? I spent the best part of last evening and this morning conducting tests, comparing with K110D, updating firmware (to 1.01 and then 1.02), reading this and other forums... and instead of solutions arrived at a new relationship with the beast: "Pentax problems are not to be solved, they are to be loved"!

Try this: update your K7 firmware to 1.02, turn OFF noise reduction on long exposures, then do two shots at high ISO, say 1600, both for 10s, but one on Manual, the other on Bulb. If things work on your camera as they do on mine, what you will get is hot pixels on the Manual shot, but no hot pixels on the Bulb shot, even though there was no noise reduction going on after the Bulb exposure!


Unreal! And enough for me to forget the whole problem, since I discovered that my aged old version of ACR does indeed fight the little pixies very efficiently anyway.

Here's looking forward to the next firmware update and more loveable weirdness!

Long live Petax and all Pentaxonians!

That is great!
Why don't you take a look into this thread I started and report your experience with the K7.
https://www.pentaxforums.com/forums/pentax-dslr-discussion/80718-k7-noise-again.html
I am very happy to see that you are having great results with your K7. My worry has been all about noise/K7.
JP

11-21-2009, 11:16 AM   #9
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What are Dark Frames and why would you need to do them?
11-21-2009, 11:23 AM   #10
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Basically, when you take a long exposure, in the K7 and K20, longer than 30 seconds, the camera takes another exposure of equal length with the mirror down and subtracts it from the first one. As mentioned above, it is to remove hot pixels and constant noise from the photo. The problem is just that it doubles the length of time it takes to get your exposure. The good thing is that it helps considerably with noise/hot pixels.
11-22-2009, 05:45 AM   #11
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Is it just me or has anyone else noticed that the DFS (Slow Shutter Speed Noise Reduction) setting on K7 has no effect? Bulb exposures always use it, while other exposure modes never use it - regardless of whether the feature is turned on or off.

Also, in my tests, DFS does not double Bulb exposures. On exposures of a few seconds, up to about 6, the subtraction is instant (although it might only be instant if the feature is OFF, I need to check again). On longer exposures, the delay doesn't match the exposure time, it's shorter.

Further, there is a funny noise I can hear during DFS if I put my ear to the camera, as if the sensor is being shaken. I only hear this noise during DFS, so I don't think it's a physical malfunction.

All in all, this feature of the otherwise lovely K7 is an embarrassing mess. This is mean't to be a semi-pro camera!
11-22-2009, 06:30 AM   #12
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I've just run some more tests, and indeed, up to 29 seconds exposure in Bulb, if DFS is turned off, DFS actually does happen, but instantly! A different algorithm seems to be used, not real DFS but noise reduction (even if High ISO Noise Reduction is also turned off!). I say this because the overall noise is lower on Bulb exposures in comparison with shots of the same duration done on Manual.
11-22-2009, 06:37 AM   #13
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QuoteOriginally posted by pentup007 Quote
Is it just me or has anyone else noticed that the DFS (Slow Shutter Speed Noise Reduction) setting on K7 has no effect? Bulb exposures always use it, while other exposure modes never use it - regardless of whether the feature is turned on or off.
Have you upgraded to Firmware 1.02 ?
It definitely has an effect. If you turn it OFF, either Bulb or Manual Mode, it will not kick in below 30 secs. Manual mode can't exceed 30s anyway. But on Bulb mode, it will force DFS above 30 secs.
If you turn it ON, it may or may not kick in for exposure less than 6 secs - the camera has its own logic.

QuoteOriginally posted by pentup007 Quote
Also, in my tests, DFS does not double Bulb exposures. On exposures of a few seconds, up to about 6, the subtraction is instant (although it might only be instant if the feature is OFF, I need to check again).
You have obviously got it off, or possibly on Low ISO (may not kick in on relatively short exposures) - page 94 of the K-7 manual


QuoteOriginally posted by pentup007 Quote
On longer exposures, the delay doesn't match the exposure time, it's shorter.
The exact DFS time may not exactly match the exposure time. I'm not sure what the logic is.

QuoteOriginally posted by pentup007 Quote
Further, there is a funny noise I can hear during DFS if I put my ear to the camera, as if the sensor is being shaken. I only hear this noise during DFS, so I don't think it's a physical malfunction.

All in all, this feature of the otherwise lovely K7 is an embarrassing mess. This is mean't to be a semi-pro camera!
The sensor is active during DFS. Its definitely doing "Something" even though the LCD screen and everything else seems to be shut down.

Don't know why you think its an embarrassing mess.

Read the manual, please, or get help like on this forum, before you pass judgement.
11-22-2009, 07:31 AM   #14
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Dearest Kittykat - that's a lovely name, by the way - I'm glad to hear your standards and expectations of semi-pro gear are lower than mine, it obviously works for you. But you do seem deficient in reading skills, so you're not really positioned to lecture anyone. Because if you had read my original post you'd know that I've indeed updated to Firmware 1.02.

But why argue with friends, when you can repeat the experiment that I've conducted and see if your results match mine. Try this: turn off ALL Noise Reduction features. Take two exposures of 10 seconds at 1600 ISO, one on Bulb, the other on Manual. What difference between the images do you see? If your camera works like mine, you'll see no hot pixels on the Bulb picture, while plenty of them on the Manual one. In addition, the Bulb image will have softer noise than Manual.

Now if you do this and report back, we can talk. But if you want to continue lecturing about reading the manual and my judgement - all the very best to you!

QuoteOriginally posted by kittykat46 Quote
Have you upgraded to Firmware 1.02 ?
It definitely has an effect. If you turn it OFF, either Bulb or Manual Mode, it will not kick in below 30 secs. Manual mode can't exceed 30s anyway. But on Bulb mode, it will force DFS above 30 secs.
If you turn it ON, it may or may not kick in for exposure less than 6 secs - the camera has its own logic.



You have obviously got it off, or possibly on Low ISO (may not kick in on relatively short exposures) - page 94 of the K-7 manual




The exact DFS time may not exactly match the exposure time. I'm not sure what the logic is.



The sensor is active during DFS. Its definitely doing "Something" even though the LCD screen and everything else seems to be shut down.

Don't know why you think its an embarrassing mess.

Read the manual, please, or get help like on this forum, before you pass judgement.
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