K20D low ISO noise...

Started Dec 18, 2008 | Discussions
nigbat Senior Member • Posts: 1,940
K20D low ISO noise...

Anyone else noticed this ?

I've been getting significant noise in plain areas (sky, or plain walls etc.) in decent light at relatively low ISO settings.

It shows up in either the red or blue channel, depending on the light source (daylight, tungsten etc) - whichever one is getting the least light
Surely at ISO 200, there shouldn't be much at all ?.

Here's an example. The red channel has significant noise, (and what seems to be a bit of VPN about a third of the way across, but might be a very faint vapour trail in the sky). Green and blue channels are fine.

Crops (unsharpened) are at 50%, not 100%, which suggests how visible the noise is.
Any ideas ?
Red channel:

Green:

Blue:

Dark Mist Contributing Member • Posts: 559
Are you taking jpegs or RAW?

If jpeg, what sort of in camera sharpening and contrast settings are you using?

Are you intending to convert to monochrome? If so are you intending to only use the red channel? If you mix the channels does the noise disappear or at least reduce to acceptable levels?

Is the noise chroma or luminance?

Regardless of the above, it is logical that the BLUE sky would be the area that would show the most noise in the RED channel.

OP nigbat Senior Member • Posts: 1,940
Re: Are you taking jpegs or RAW?

Good questions.

They were from a JPEG, as my current copy of Photoshop (CS2) won't open K20D RAW files, and the Pentax software is slooooow.
In camera sharpening and contrast were low.

The B&W question really isn't relevant. I'm wondering where all that noise comes from (it's quite visible in colour too). Sure the red photosites are getting less light , but it's not pitch black, and this is ISO 200.

Tried the RAW file in Pentax Photolab (zero contrast applied, zero sharpening). It's quite a bit better, but even so...

Scottie137 Regular Member • Posts: 259
Adobe DNG converter is Free

You should download Adobe's latest DNG converter. It is a free download and will convert all your PEFs to DNGs for use in CS2....

Sentas Forum Member • Posts: 59
Re: Adobe DNG converter is Free

Hi

when You use CS2 then You should be able to ACR (Adobe Camera Raw whits is free to download) and I prefer to use DNG format insted of PEF also because its bigger
Colourspace… Raw is so big inprovement, But it take a little longer
YES, I now I am a terribel speller, but my xcuse: I am old danish guy (:–P
Sentas

Andrew C Junior Member • Posts: 44
Re: Adobe DNG converter is Free

Yuck.

I can't think JPEG is the cause or this. If you have to use RAW to get rid of that kind of noise at ISO 200 there is a problem (either with the camera specifically or the K20 in general).

OP nigbat Senior Member • Posts: 1,940
Re: Adobe ACR

The more recent upgrades of ACR are only compatible with the latest version of Photoshop, not CS2.

I think this is a deliberate Adobe policy to obsolete previous versions fairly quickly. Given the cost of the program, it's a pretty obnoxious policy.

viking79
viking79 Forum Pro • Posts: 14,157
Re: Adobe ACR

Agreed, I have noticed this too. For the cost of these programs Adobe should support them for at least 4 years. Their policy is to stop releasing updates as soon as the new version is out. That is unacceptable to me.
--
See my Flickr Photostream: http://www.flickr.com/photos/28177041@N03/
See my PPG Shots: http://www.pentaxphotogallery.com/erictastad
See my Blog/Page: http://web.me.com/atastad/viking79/Welcome.html

 viking79's gear list:viking79's gear list
Sony a7R Samsung NX1 Samsung NX 30mm F2 Pancake Samsung NX 85mm F1.4 ED SSA Samsung NX 60mm F2.8 Macro ED OIS SSA +5 more
Tan68
Tan68 Veteran Member • Posts: 5,792
Re: K20D low ISO noise... halo
-- hide signature --

what is causing the halo around the chimney in the red channel pic ?

 Tan68's gear list:Tan68's gear list
Phase One Capture One Pro +1 more
Scottie137 Regular Member • Posts: 259
Re: Adobe ACR

But DNG Converter has nothing to do with ACR? Not sure if you meant to respond to my post, but if you download the Adobe DNG Converter 5.2 update, you can convert the K20 files to DNG (even batch them) then the DNGs should open just fine in CS2....

Russ Houston
Russ Houston Veteran Member • Posts: 6,377
extended dynamic range?

Are you using the extended dynamic range option? I've noticed low ISO noise when I use that option.
--
Russ
http://www.flickr.com/photos/rfortson/
http://www.pentaxphotogallery.com/russfortson
Even bad photography can be fun

 Russ Houston's gear list:Russ Houston's gear list
Olympus OM-D E-M5 Olympus PEN E-P5 Olympus M.Zuiko Digital ED 9-18mm F4.0-5.6 Olympus M.Zuiko Digital ED 14-42mm 1:3.5-5.6 Olympus M.Zuiko Digital ED 14-150mm 1:4-5.6 +7 more
OP nigbat Senior Member • Posts: 1,940
Re: extended dynamic range?

In this case, yes.

That's interesting, thanks. When we get some more blue sky I'll do some tests with it turned off.

OP nigbat Senior Member • Posts: 1,940
Re: Adobe ACR

Thanks, I'll check out the DNG converter.

OP nigbat Senior Member • Posts: 1,940
Re: Adobe DNG

Just downloaded, and tried it on the same image.

Works great, and the resulting conversion lacks the noise artifacts produced by Pentax Photolab. Thanks again.

I never shot JPEGs with the K10D, and I'll be giving up on them with the K20D as well, I think.

Jon Schick Veteran Member • Posts: 5,042
Re: extended dynamic range?

I bet this is the issue - I have been surprised by the additional noise (in shadow areas in my case) when using the extended dynamic range option - even when ISO is set to 200, which is as low as you can go. I don't think Pentax is the only culprit here - tests of other cameras also comment on increased noise when the dynamic range options are used.

I've therefore decided to pretend the camera doesn't offer this, and leave it permanently off. I don't find this to be a big issue as it wasn't a major reason why I wanted the K20D - and have otherwise been very pleased with the camera even at quite high ISOs. I leave it on auto 100-400 normally, and would be happy to take it to 800 and possibly higher if necessary. I kept the K10D at ISO640 or below except in case of emergency.

Would be interested to hear whether this is the source of your problem.

-- hide signature --
 Jon Schick's gear list:Jon Schick's gear list
Fujifilm X100V Leica M10 Fujifilm X-T4 Carl Zeiss Biogon T* 2,8/25 ZM Carl Zeiss C Biogon T* 2,8/35 ZM +7 more
OP nigbat Senior Member • Posts: 1,940
Re: extended dynamic range?

It's clearly not the whole issue, as the RAW files still show some of this noise when processed using the Pentax software, whereas it's almost gone using ACR.

Russ Houston
Russ Houston Veteran Member • Posts: 6,377
Re: extended dynamic range?

nigbat wrote:

It's clearly not the whole issue, as the RAW files still show some of
this noise when processed using the Pentax software, whereas it's
almost gone using ACR.

I think you'll be surprised by how much noise the EDR introduces. I don't really use it much anymore because of this.
--
Russ
http://www.flickr.com/photos/rfortson/
http://www.pentaxphotogallery.com/russfortson
Even bad photography can be fun

 Russ Houston's gear list:Russ Houston's gear list
Olympus OM-D E-M5 Olympus PEN E-P5 Olympus M.Zuiko Digital ED 9-18mm F4.0-5.6 Olympus M.Zuiko Digital ED 14-42mm 1:3.5-5.6 Olympus M.Zuiko Digital ED 14-150mm 1:4-5.6 +7 more
senasnamas New Member • Posts: 1
what does it mean "extended dynamic range option"?

... and where this option could be found at K20D?

OP nigbat Senior Member • Posts: 1,940
Re: what does it mean "extended dynamic range option"?

Fn menu - select ISO - press Fn button.
That enables extended dynamic range. To deselect it, repeat the procedure.

Keyboard shortcuts:
FForum MMy threads