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12-12-2012, 06:51 AM - 3 Likes   #1
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Darktable is getting profiled noise reduction

I saw this and had to try it for myself:
profiling sensor and photon noise | darktable

It is still under development and of course the K-5 wasn't already profiled. I figured I'd have a go at it, it wasn't an easy process, but I have profiled the K-5.

Here is a 100% crop I did at 6400 ISO, absolutely no noise reduction on the left and the right was done by just enabling the profiled NR for 6400 ISO, just one click.
http://i.imgur.com/lugD7.jpg

I've submitted the profile to the developers so K-5 users in the future can have it working out of the box. If I get around to it I'll do the K100D too.

12-13-2012, 08:11 PM   #2
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Yes, I knew johannes was working on this but had not seen it in action. Pretty impressive!. Thanks for doing the profile.

Jack
12-13-2012, 08:23 PM - 1 Like   #3
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Doing the profiling the first time was the hard part, doing it again is significantly easier because I know the process and have the bugs worked out. I did the K100D in about 20 minutes including taking the pictures and recompiling to add the profile and test it.

If anyone wants a camera profiled and doesn't want to go through the technical stuff, just take the pictures needed and upload them, I'll make the profile. Just follow his directions on the blog post for taking the picture, a good thing to use is a bright window on a dark wall, that gives you the under and overexposure. Keeping it out of focus gives the gradients in between. I just did the full stops and didn't bother with 1/2 or 1/3 stops, those can be calculated well enough that it wouldn't do much good. Sv mode is pretty handy for this, lock the exposure, shoot, turn the dial, shoot, turn, shoot.

I know someone was talking about doing a K-7, I've done the K100D and K-5. It would be interesting to see the difference between the original K-5 and the others with the same sensor.
12-29-2012, 05:25 PM   #4
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I'd be interested in getting a profile done of the K-x. I can upload the photos if you'd like.


Second thought, how do I make the overexposed and underexposed photos first?

12-29-2012, 05:40 PM   #5
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QuoteOriginally posted by DanCar Quote
Second thought, how do I make the overexposed and underexposed photos first?
I used a bright window beside a dark wall. It needs to be mostly white light, so all channels are showing something similar. It also must be totally out of focus, no sharp details.
12-30-2012, 10:14 AM   #6
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http://db.tt/9D0Pr4H5

Here's a dropbox folder with my first attempts across all ISOs 400-6400. Are these a good start or should I try again?
12-30-2012, 11:04 AM   #7
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The histogram has to show peaks at both sides, it will be a U shape, I didn't see that in the 5 I checked. What I did was meter for the wall, then underexpose it by 2 stops, the overexposure took care of itself.
12-30-2012, 12:50 PM   #8
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Just updated the photos in the file. Not sure if any are better.

12-30-2012, 04:15 PM   #9
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This one of 6400 was a good one, a lot of them had too much detail, you can't have any hard edges, it has to be all out of focus to get the gradients between under and overexposure. A lot of the others didn't have enough on the underexposure end.

The base ISO needs to be represented too, it doesn't hurt to do the extended ones like 100 and 12800 either.

Also, to save me time, no spaces in the file names, took me a few minutes to figure out why the script kept freaking out.

EDIT: Just saw in the tracker that the K-x has been added by someone.
Attached Images
View Picture EXIF
PENTAX K-x  Photo 

Last edited by elliott; 12-31-2012 at 04:13 PM.
01-01-2013, 02:59 AM   #10
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I tried to do the k-7 last night, but I didn't seem to have the tools in my install (1.1.1 on ubuntu)

I then followed the instructions to install fron GIT (no real idea what that means!) but then I couldn't run darktable at all.

I will upload my images when I get chance - may have to create a dropbox account too. Thanks!
01-01-2013, 04:04 AM   #11
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Here is a zip of images taken with the k-7 at all ISOs (in 1/3 steps)

It's 250MB though - let me know if that's too big and you'd rather a better solution. Thanks again.

http://ubuntuone.com/7Xnm3X3cIONrK6yoDVtaIa
01-01-2013, 08:53 AM   #12
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The link doesn't seem to be working.
01-01-2013, 04:57 PM   #13
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Sorry about that - I closed my laptop before it had finished uploading - d'oh!

It works for me now.

Thanks again.
01-01-2013, 06:05 PM   #14
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I do see that there wasn't enough blue from your light, I don't think it currently matters, since it just uses green and interpolates the rest. If he does some major changes in the future it might need to be re-profiled though.

It seems to be working fine, send me a test shot if you'd like to see it in action.
01-02-2013, 07:59 PM   #15
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great, good to see so many people using darktable here.
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