Am Wed, 24 May 2017 19:16:15 +0300 schrieb Roman Lebedev <lebedev...@gmail.com>:
> On Wed, May 24, 2017 at 7:05 PM, Аl Воgnеr <darktable...@corr.eu.org> > wrote: > > Am Wed, 24 May 2017 16:04:25 +0300 > > schrieb Roman Lebedev <lebedev...@gmail.com>: > > > >> On Wed, May 24, 2017 at 3:49 PM, Аl Воgnеr > >> <darktable...@corr.eu.org> wrote: > >> > I read > >> > http://www.darktable.org/2012/12/profiling-sensor-and-photon-noise/ > >> > and want to create noise profile images with a Pentax KP. > >> > > >> >> take one shot per iso. > >> > > >> > 1 step ISO, 1/2 steps or 1/3 steps? Smaller steps will produce a > >> > lot of photos, the Pentax KP supports 819200 ISO. > >> Basically, all the ISO that can be set in camera. So certainly 1/3. > >> And if with 1/2, different values can be set, maybe those too. > >> > >> If the profile for a given iso does not exist, it will be linearly > >> interpolated from the nearest samples on the each side. > > > > Ok, so I will produce tons of RAWs > > > > Does it matter if they are in DNG or PEF, or do you want both? > It does not matter. If some camera can produce DNG, it is pretty much > always better to use DNG. > > >> >> it has to be out-of-focus and have a widespread histogram, i.e. > >> >> be over- and underexposed at the same time (see example image > >> >> below). if you want to be thorough, take 2-3 to verify the > >> >> numbers. > >> > > >> > So it should not be a normal sharp nightshot, but something out > >> > of focus, eg a street lamp in the night? > >> I'd try to search for raws used for noiseprofile generation for > >> some other camera and examining them. But yes, something like > >> bright lamp illuminating half of the shot, and total darkness on > >> the other half, with gradient change from one to the other one. > > > > Is indoor preferred? I remember very noisy pictures in winter, which > > were not noisy actually. It was warm wet air / fog in certain areas > > only. Especially blue at dawn looked very noisy. > Can't say, experiment. In-doors should work fine. > > >> >> this image looks very green, because the `raw linear' style has > >> >> been applied to it (find it in darktable/tools/noise). this > >> >> makes sure we get linear camera raw rgb with no basecurves, no > >> >> whitebalance, etc in the way. it is essential that you apply > >> >> this style. > >> > > >> > So I have to change the camera to RGB? Are sRGB *and* RGB photos > >> > wanted? > >> That is talking about the dt processing. > >> Unless the manufacturer is *really* *really* dumb the in-camera > >> color space selection only matters for the JPEG's, and the embedded > >> thumbnails. > > > > Ok, there are so much setting at Pentax cameras, which seem to > > influence noise, but should work only with jpeg. Probaby it is best > > to turn them off anyway. > Probably, yeah, but should not really matter. > > > Should these files be uploaded to https://raw.pixls.us ? > Hell no. Here is 1 sample with 10000ISO: https://www.file-upload.net/download-12516482/pentax.kp.dng.noise.sa_1.8_2.41_10000i.dng.html Can this be used for noise calibration? Please note: [EXIF] 0xc62b Baseline Noise : 1 [MakerNotes] 0x0049 Noise Reduction : Off [MakerNotes] 0x0071 High ISO Noise Reduction : Off; Inactive Default is "High ISO Noise Reduction" on, which is probably used by everyone. I don't know if this influences the raw-file I have these samples from 100ISO - 819200ISO in 1/3 steps. (1.4GB) Please let me know how to go on. Al ____________________________________________________________________________ darktable user mailing list to unsubscribe send a mail to darktable-user+unsubscr...@lists.darktable.org
