Just an observation

Liney · 10-11-2014, 11:18 PM

Just thought I would share this with the forum and see if anyone has any insights.

I took some shots of the eclipse of the moon during the week in RAW format, and uploaded them to my PC. I opened them using RAW Therapee which is my usual RAW viewer, and they were so noisy it was hard to see the moon at all! The noise on the image was like you used to get from an analogue tv with a wire coat hanger for an aerial, and any attempt to cancel it out was useless.

I had a look around for another RAW viewer to get a second opinion, and ended up downloating a plug-in for GIMP called UFRaw. Once I'd installed it and got it working, opening the same images in the new viewer and hey presto all the noise is gone.

So I'm a little confused, how can two different applications which are both opening the same image have such different results?

Anyone seen a similar effect?

**Kerrowdown** · 10-12-2014, 02:46 AM - **1 Like**

Out of interest if you delete the original image in RAW Therapee and open a new uploaded version of the same image, is it still the same?.

I'm just wondering if it was to do with upload to the PC/Raw Therapee that's the culprit in this case.

jimr-pdx · 10-12-2014, 10:36 AM - **1 Like**

I know that Picasa often shows my DNG files as a psychadelic noisy mess next to the jpeg, but opening in Elements resets the base points so the image looks like a raw file should look. Picasa also uses a common conversion tool, dcraw or one of those.

Adam · 10-12-2014, 12:09 PM - **1 Like**

Originally posted by Liney

Just thought I would share this with the forum and see if anyone has any insights.

I took some shots of the eclipse of the moon during the week in RAW format, and uploaded them to my PC. I opened them using RAW Therapee which is my usual RAW viewer, and they were so noisy it was hard to see the moon at all! The noise on the image was like you used to get from an analogue tv with a wire coat hanger for an aerial, and any attempt to cancel it out was useless.

I had a look around for another RAW viewer to get a second opinion, and ended up downloating a plug-in for GIMP called UFRaw. Once I'd installed it and got it working, opening the same images in the new viewer and hey presto all the noise is gone.

So I'm a little confused, how can two different applications which are both opening the same image have such different results?

Anyone seen a similar effect?

There generally will be a lot of visible noise if no color noise reduction is applied to a high-iso raw file; many (most?) raw converters do this by default. So my guess would be that this might be the culprit.

Adam
PentaxForums.com Webmaster (Site Usage Guide | Site Help | My Photography)

PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

Liney · 10-13-2014, 04:01 AM

Thanks folks, some useful ideas. I'll have a try with some similar shots in the next week or so and see if I can nail it down. Or maybe not...

10-11-2014, 11:18 PM	#1
Liney Veteran Member Join Date: Apr 2013 Posts: 1,237	Just an observation Just thought I would share this with the forum and see if anyone has any insights. I took some shots of the eclipse of the moon during the week in RAW format, and uploaded them to my PC. I opened them using RAW Therapee which is my usual RAW viewer, and they were so noisy it was hard to see the moon at all! The noise on the image was like you used to get from an analogue tv with a wire coat hanger for an aerial, and any attempt to cancel it out was useless. I had a look around for another RAW viewer to get a second opinion, and ended up downloating a plug-in for GIMP called UFRaw. Once I'd installed it and got it working, opening the same images in the new viewer and hey presto all the noise is gone. So I'm a little confused, how can two different applications which are both opening the same image have such different results? Anyone seen a similar effect?

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Corporate Profits Just Hit An All-Time High, Wages Just Hit An All-Time Low Read mor	jeffkrol	General Talk	7	06-26-2012 02:56 PM
An observation, or am I just biased?	amc654	Pentax DSLR Discussion	25	01-12-2012 11:38 AM
Just a positive anecdotal observation on Pentax popularity	mattdm	Photographic Industry and Professionals	23	10-25-2011 07:17 AM
An observation regarding minimum aperture.	atyab	Pentax DSLR Discussion	6	12-31-2008 02:08 PM
SMC and Takumars: an observation.	JonPB	Pentax SLR Lens Discussion	23	11-20-2008 03:37 AM

10-12-2014, 02:46 AM - 1 Like	#2
Kerrowdown PEG Moderator Join Date: Aug 2008 Location: Highlands of Scotland... "Hold Infinity in the palm of your hand" - William Blake Photos: Gallery Posts: 57,819	Out of interest if you delete the original image in RAW Therapee and open a new uploaded version of the same image, is it still the same?. I'm just wondering if it was to do with upload to the PC/Raw Therapee that's the culprit in this case.

10-12-2014, 10:36 AM - 1 Like	#3
jimr-pdx Pentaxian Join Date: May 2010 Location: now 1 hour north of PDX Photos: Gallery \| Albums Posts: 3,897	I know that Picasa often shows my DNG files as a psychadelic noisy mess next to the jpeg, but opening in Elements resets the base points so the image looks like a raw file should look. Picasa also uses a common conversion tool, dcraw or one of those.

10-12-2014, 12:09 PM - 1 Like	#4
Adam Administrator Site Webmaster Join Date: Sep 2006 Location: Arizona Photos: Gallery \| Albums Posts: 51,595	Originally posted by Liney Just thought I would share this with the forum and see if anyone has any insights. I took some shots of the eclipse of the moon during the week in RAW format, and uploaded them to my PC. I opened them using RAW Therapee which is my usual RAW viewer, and they were so noisy it was hard to see the moon at all! The noise on the image was like you used to get from an analogue tv with a wire coat hanger for an aerial, and any attempt to cancel it out was useless. I had a look around for another RAW viewer to get a second opinion, and ended up downloating a plug-in for GIMP called UFRaw. Once I'd installed it and got it working, opening the same images in the new viewer and hey presto all the noise is gone. So I'm a little confused, how can two different applications which are both opening the same image have such different results? Anyone seen a similar effect? There generally will be a lot of visible noise if no color noise reduction is applied to a high-iso raw file; many (most?) raw converters do this by default. So my guess would be that this might be the culprit. Adam PentaxForums.com Webmaster (Site Usage Guide \| Site Help \| My Photography) PentaxForums.com server and development costs are user-supported. You can help cover these costs by donating or purchasing one of our Pentax eBooks. Or, buy your photo gear from our affiliates, Adorama, B&H Photo, KEH, or Topaz Labs, and get FREE Marketplace access - click here to see how! Trusted Pentax retailers:

10-13-2014, 04:01 AM	#5
Liney Veteran Member Join Date: Apr 2013 Posts: 1,237 Original Poster	Thanks folks, some useful ideas. I'll have a try with some similar shots in the next week or so and see if I can nail it down. Or maybe not...