turn off DFS with your K20D and K7

---All at your own risk---

Here is a little hack to turn off the DFS (dark frame Subtraction) with the camera's you aren't able to.

http://pentaxda.deviantart.com/blog/35052539/
if it's to complicated you can download the needed "hack" file here link

It's the same some of you have used to get the auto focus adjustment with the K10D but if you know the codes you can enable or disable other things like the DFS.

I've the K10D and you can just turn off the DFS there so didn't couldn't try it.

---All at your own risk---

Can't get this to work on my K20D yet.

be sure to press "enter" when you finish with the less line of codes and leave the battery door open.
Those where the problems most K10D user had when trying to get the AF adjustment to work.

Just see the typo
It must be: turn off DFS on your K20D and K7

Ahhhh, [enter] The text file I created proibably doesn't have a LF ( line feed )

I can get in the debug menu and enable debug mode OK. I can see teh same AF Afjustment as I can on my K10D. I'll edit the text sys parameter txt file and try again.

just tried again and it doesn't work. Took a 10 second exposure. Couldn't take another one for about 10 seconds.

Why don't you download the files and see if they work? link

For the K20D you need to copy these file to the SD card.
- MODSET.442
- SYSPARAM.TXT

Than
- open the SD card door
- press and hold delete when turning the camera on

Than you get a menu and you need to enable the debug menu by doing this:
- Press right key to change DIS to EN on the DEBUG MODE line.
Press OK

That should be it.

Done all that. several times. Don't work.

too bad
I can't help you further either.

I could see if someone on Deviantart wants to help you?

Thanks Stefan.

I can get into debug mode no problem whatsoever. I'm well versed with this now after my K10D AF calibrations. In fact teh K10D is always in debug mode on shoots now.

So the problem must be in trying to get the K20D to read the sysparam.txt file

I can't see the DisableNR parameter in the debug menu so it must only be accessed via a text file.

Yes you're right about that, it's quite strange it doesn't want to work

OK, I dunno what went wrong before but I got it to work this time.

I was able to get into the debug menu before and eable debug mode so it must have been a problem with the sysparam.txt I guess.

I took an 8" exposure and pic appeared immediately. I then turned off debug mode and took another 8" exposure. Had to wait another damn 8" before I could use the camera. As it dark I'll do some tests outside with long exposures of say 1 or 2 minutes and check the difference in IQ with the NR on or off.

Thank you Smeggy this great news!
Hopefully it also work for others.

I'm still unsure of why it didn't work before.

the only thing I can think of is this ...


1] put modset file into root. didn't work

2] copied modset file to DCIM folder it then worked. However it could have been the original root modset file that then worked.

3] put sysparam file into DCIM because I thought it was the working path because of step 2]


... or something like that anyway

I haven't managed to do a test yet. I'll try and remember tonight.

If there's an appreciable difference in IQ it's probably worth the extra wait for exposures upto around 10 seconds, if not then it's debug mode all the way

The DFS is there to get the fixed noise out.
I'm going to quote Cambridge in colour now link

Fixed pattern noise includes what are called "hot pixels," which are defined as such when a pixel's intensity far surpasses that of the ambient random noise fluctuations. Fixed pattern noise generally appears in very long exposures and is exacerbated by higher temperatures. Fixed pattern noise is unique in that it will show almost the same distribution of hot pixels if taken under the same conditions (temperature, length of exposure, ISO speed).

Most RAW programs of these days however already have algorithm in it to define hot pixels so they already get filtered out these days, DFS is not really needed any more.
However if you''re going to take photos of the night sky it will be better to make one Dark Frame to see where the fixed noise is and with a program you can get the noise out of all the exposures before you stack them.