Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
04-01-2016, 11:34 PM   #1
Pentaxian
mgvh's Avatar

Join Date: Sep 2010
Location: MD
Photos: Gallery | Albums
Posts: 833
Help me understand RAW / DNG processing

I have a K-30 and a K-x. I shoot DNG with both. I was trying to compare how the same lens renders differently on the two cameras by shooting the same scene.
(Some interesting differences, especially in metering, but that's not the point here.)
To make quick comparisons, I usually compare shots using FastStone Image Viewer.
Since the metering was different, I brought them into Lightroom, but before I applied an Auto adjust to every pic, I used the compare feature there, and here is where my question emerges.
Is there some underlying engine that controls how a program renders DNG files? Should DNG files look the same regardless of program, or will they be different?
Especially with regard to noise, the images looked rather different in FastStone as compared to Lightroom. (The K-30 ones looked better in FastStone; the K-x in Lightroom.)
If it is the case that each program renders differently, then how do you determine what's the best way to do post-processing?

04-01-2016, 11:55 PM   #2
Loyal Site Supporter
clackers's Avatar

Join Date: Jul 2013
Location: Melbourne
Photos: Albums
Posts: 8,042
It doesn't matter how the software begins its RAW development process, Mgvh, only how you finish it then export to final JPG or whatever.

They each start with different assumptions, so did the camera when it made the preview embedded in the DNG file.
04-02-2016, 12:55 AM   #3
Pentaxian




Join Date: Jan 2012
Location: Slovenia
Posts: 2,162
QuoteOriginally posted by mgvh Quote
If it is the case that each program renders differently, then how do you determine what's the best way to do post-processing?
That is the case (raw files have to be "developed" anyway to be shown on your screen, and each program does that differently). You can try with different presets (don't know about Faststone but Lightroom has some).
Finding "the best way" is usually trial and error, yours or someone elses.
04-02-2016, 05:29 AM   #4
Pentaxian




Join Date: Oct 2009
Location: Far North Qld
Posts: 3,262
QuoteOriginally posted by mgvh Quote
To make quick comparisons, I usually compare shots using FastStone Image Viewer.

Especially with regard to noise, the images looked rather different in FastStone as compared to Lightroom. (The K-30 ones looked better in FastStone; the K-x in Lightroom.)
Unless you subsequently press 'A' to have Faststone render from RAW, Faststone is initially showing you the JPG preview file which has your camera settings already baked in.
Faststone's RAW to bitmap rendering is quite different and very bland (as it should be for RAW) whereas LR is applying some basic assumptions.

04-02-2016, 05:32 AM   #5
Pentaxian
wstruth's Avatar

Join Date: Nov 2010
Location: at my kitchen table
Photos: Gallery | Albums
Posts: 405
QuoteOriginally posted by mgvh Quote
If it is the case that each program renders differently, then how do you determine what's the best way to do post-processing?
I recommend you use whichever program you feel most comfortable with. Auto adjustments can be a good place to start and then tweek the results. Lightroom usually lightens the image too much for my liking when I use auto, so that will be the first thing i adjust. I've used Lightroom, Faststone and others, and often go back to Faststone for quick tweaks of Jpegs, but lately Lightroom is my go to.
04-02-2016, 06:52 AM   #6
Site Supporter
stevebrot's Avatar

Join Date: Mar 2007
Location: Vancouver (USA)
Photos: Gallery | Albums
Posts: 26,463
QuoteOriginally posted by mgvh Quote
Is there some underlying engine that controls how a program renders DNG files?
Yes, the program is that engine. Before it does its work, there is no image and how that engine approaches its task determines how the final product turns out.

QuoteOriginally posted by mgvh Quote
Should DNG files look the same regardless of program, or will they be different?
No. That would be nice or perhaps it might not. The different RAW image processors tend to produce somewhat different results and it may be difficult to emulate the output from one when using another.

QuoteOriginally posted by mgvh Quote
Especially with regard to noise, the images looked rather different in FastStone as compared to Lightroom.
I am not a FastStone user, but if my memory serves me correct, there may be some confusion as to whether the viewer shows the JPEG preview (bundled in with the RAW file) or an actual conversion. The appearance of the JPEG preview is determined by the camera's JPEG settings. Edit: I just noticed that @Steve.Ledger made a more complete explanation above


Steve
04-02-2016, 08:09 AM   #7
Pentaxian




Join Date: Sep 2008
Location: Phoenix, AZ
Posts: 1,420
it could also be your color space presets.

for instance, you may be shooting sRGB and importing them into Faststone as sRGB, yet Lightroom may be set to convert to AdobeRGB color space on import.

I shoot AdobeRGB and use ProPhoto color space and when I want to post something here, I need to reprocess as sRGB or things look nasty green.

That's just once example.
04-02-2016, 08:55 AM   #8
Pentaxian
mgvh's Avatar

Join Date: Sep 2010
Location: MD
Photos: Gallery | Albums
Posts: 833
Original Poster
Thank you, all! That helps.
That does make perfect sense that FastStone is basically doing a JPEG preview. What I see is what I save (as JPG) is what I get.
And now I went into Lightroom, and I see that when I import DNG files, I do have a choice of "Develop Settings." I have always just left that set at "none," but I see that I can apply any preset when importing.
So, when I do a comparison in FastStone, it seems to be showing me not the actual RAW/DNG but what the pics have the potential of looking like (as JPGs).
When I compare them in Lightroom, I am seeing what the unprocessed RAW/DNG has rendered. It's up to me, then to apply whatever processing to the RAW/DNG before I export as JPG.

@wstruth: Yes, the Auto adjustment in LR is too bright for my taste as well. I was using it in test comparisons to take out the element of metering differences between the two cameras. I figure Auto is using some algorithm to create a similarly bright image, and it does seem to do that.

Thanks again.

04-02-2016, 09:59 AM   #9
osv
Pentaxian




Join Date: Mar 2007
Location: So Cal
Photos: Gallery
Posts: 2,080
QuoteOriginally posted by mgvh Quote
I have a K-30 and a K-x. I shoot DNG with both. I was trying to compare how the same lens renders differently on the two cameras by shooting the same scene.
it helps to use a fixed and hopefully matched white balance setting for both cameras, like the daylight preset, shot at the same time of day... although you could attempt to match 'em both in the raw processor.

i'd be doing it in full manual mode, unless you are comparing the way that the cameras meter against each other.

using different raw processors complicates the goal of comparing camera bodies on the same lens.
04-02-2016, 07:14 PM   #10
Pentaxian
Cee Cee's Avatar

Join Date: Aug 2011
Location: Glenroy, Melbourne
Photos: Gallery | Albums
Posts: 2,983
QuoteOriginally posted by mgvh Quote
@wstruth: Yes, the Auto adjustment in LR is too bright for my taste as well.
is your monitor calibrated, usually an uncalibrated monitor displays a brighter picture than a calibrated one, the LR Auto adjustment may assume a calibrated monitor
04-02-2016, 09:24 PM   #11
Pentaxian
mgvh's Avatar

Join Date: Sep 2010
Location: MD
Photos: Gallery | Albums
Posts: 833
Original Poster
QuoteOriginally posted by Cee Cee Quote
is your monitor calibrated, usually an uncalibrated monitor displays a brighter picture than a calibrated one, the LR Auto adjustment may assume a calibrated monitor
No, I don't have a calibrated monitor. I do have two monitors, and for the life of me I can't get them to match exactly. I have determined, however, by comparing images on a number of monitors and via printing, which one is closer to what most people see. The image on the monitor I prefer looks even brighter on the other monitor.
I don't think that is the main difference, though. I've been playing more with ISO and shutter speed with a set aperture. The presence of noise is not just a factor of ISO. It does also depend on the shutter speed. E.g., in low light with ISO fixed at 500, I get more noise at 1/50 than at 1/30 when they are both brightened to the same level. (The 1/50 needs more brightening than the 1/30, of course, and by 'brightening,' I'm talking about increasing exposure in LR.) The faster shutter apparently does not give enough time to pick up dark areas, and so when I brighten in LR, there is more noise.
For some reason, with a controlled scene using A mode and ISO set at 500, the K-x was choosing a slower speed than the K-30. Thus, the K-30 pics were darker, needed more brightening, and were showing considerably more noise.
When I matched everything (same ISO and f- and shutter) on both cameras, then the K-30 clearly had less noise. So, what I'm doing is adding +.7 exposure on the K-30.
This is a bit like 'shooting to the right' at least a bit more.
Of course, this may all be obvious to others, but now I get it!
04-03-2016, 02:04 AM   #12
Moderator PEG Judges
Kerrowdown's Avatar

Join Date: Aug 2008
Location: Highlands of Scotland.
Photos: Gallery
Posts: 31,343
QuoteOriginally posted by mgvh Quote
I do have two monitors, and for the life of me I can't get them to match exactly.
I would suggest buying a hardware calibration tool to resolve this and take away any future required guesswork.

I use and can recommend the X-Rite i1Display Pro, simple quick and easy.
04-03-2016, 03:36 AM   #13
Loyal Site Supporter
clackers's Avatar

Join Date: Jul 2013
Location: Melbourne
Photos: Albums
Posts: 8,042
QuoteOriginally posted by mgvh Quote
No, I don't have a calibrated monitor. I do have two monitors, and for the life of me I can't get them to match exactly.
An alternative to Kerrowdown's excellent suggestion is the Spyder I use.
04-03-2016, 03:48 AM   #14
Moderator
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 5,914
QuoteOriginally posted by clackers Quote
An alternative to Kerrowdown's excellent suggestion is the Spyder I use.
And yet another suggestion, closer to Kerrowdown's than Clackers', but a little cheaper and still excellent, is the X-rite Colormunki Display that I use. My two monitors - the built in laptop screen on my HP Envy 17 laptop, and an external HP monitor - couldn't be more different at their default settings. Using the Colormunki Display gets them very, very close indeed... almost identical, in fact.
04-03-2016, 08:02 PM   #15
osv
Pentaxian




Join Date: Mar 2007
Location: So Cal
Photos: Gallery
Posts: 2,080
QuoteOriginally posted by mgvh Quote
No, I don't have a calibrated monitor. I do have two monitors, and for the life of me I can't get them to match exactly.
this will get you in the ballpark, wrt gamma and contrast. LCD monitor test images
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
camera, compare, dng, faststone, files, k-30, k-x, lightroom, pentax help, photography, program, troubleshooting
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Abstract help me understand banding/posterization CreationBear Photo Critique 2 03-21-2015 07:37 AM
help me understand... peterjcb Pentax SLR Lens Discussion 15 02-09-2015 11:04 AM
Help me understand remote triggering... Catscradle Pentax DSLR Discussion 4 05-25-2014 06:09 PM
Help me understand some settings on K3 Please Tom777 Troubleshooting and Beginner Help 2 05-24-2014 05:39 AM
Help me understand the 645Z sensor's resolving power 6BQ5 Pentax Medium Format 21 04-26-2014 09:14 AM



All times are GMT -7. The time now is 02:23 PM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top