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07-09-2016, 10:24 AM - 1 Like   #46
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QuoteOriginally posted by mattt Quote
Another note: Getty Sports photographers for the Winter Olympics were shooting JPG files remotely and transmitting immediately as the reporting cycle is so short/tight they have no time to do post on RAW or the data transfer speed.
There are lots of cases such as this one where the light and conditions are very static. There's time to set up the JPEG contrast, saturation etc. to give a great result for that shooting session. The key is to adjust JPEG settings to match the location, light and subject matter.

Regards,
--Anders.

---------- Post added 9th Jul 2016 at 19:37 ----------

QuoteOriginally posted by Doundounba Quote
1) About "shadow protection". Camera Menu 2 -> D(ynamic)-Range Settings. There the two submenus are "Highlight Correction" and "Shadow Correction". When you talk above about "shadow protection", you mean this Shadow Correction, right? There are five possible values there (Off, Auto, Low, Mid and High), and I think that's what you're talking about.

2) About "highlight protection". Not sure what you are talking about. It could also be in the same place: Camera Menu 2 -> D(ynamic)-Range Settings -> Highlight Correction. But the only possible values for me are "Auto" or "Off", with a default to Auto. So I don't see anything that I can tweak here. But see the third point for another possible meaning.

3) In the Custom Image settings for your choice of profile. I use Natural, and in there, I can adjust seven different parameters. (If your camera shows only five, use the front wheel to get the expanded options.) They are, in order: Saturation, Hue, High/Low Key Adj, Contrast, Contrast Highlight Adjustment, Contrast Shadow Adjustment, Sharpness. Above, you are talking about using "High/Low Key Adj" to bring up the midtones. This is useful! I did not know that that is what that setting would do. Do you have any advice about what "Contrast Highlight Adjustment" and "Contrast Shadow Adjustment" do? Is that what you mean when you talk about "highlight protection"?
Yes, it's called shadow and highlight correction, not protection. You might need to set your ISO to something other than 100 to have access to highlight correction "on".

About the contrast highlight and shadow adjustment sliders, here's a rerun posting from me about those:
https://www.pentaxforums.com/forums/172-pentax-k-3/282312-contrast-highlight-...ml#post3073704

Regards,
--Anders.

07-09-2016, 11:43 AM   #47
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QuoteOriginally posted by Nicolas06 Quote
No offence but I find GIMP not the best for that kind of task.
None taken. But for me, over 90% of the time I'm just using Levels, Curves, Brightness/Contrast, Heal and/or Clone (for sensor dust) and Crop. It's not rocket science, and for this GIMP works well enough, especially for the price. (I do agree, however, that GIMP is not great to, for example, correct white balance.)

QuoteOriginally posted by asp1880 Quote
You might need to set your ISO to something other than 100 to have access to highlight correction "on".
Indeed. On my K-3, the "On" option appears from ISO 200 (it is also absent at ISO125 and 160).

QuoteQuote:
About the contrast highlight and shadow adjustment sliders, here's a rerun posting from me about those:
https://www.pentaxforums.com/forums/172-pentax-k-3/282312-contrast-highlight-...ml#post3073704
Thanks again! I think this will be helpful to me and I will be playing with these.

BTW, to get a bit more specific, here's an example of my own corner cases, those where I find I have problems with my JPGs. I do a lot of flash macro work. In fact, it's the vast majority of my shooting. Often, that means that in the background there will be some bokeh'ed leaves or other features that gradually fade to black. That's where the (JPG) image is usually the weakest.

Take this shot - with which BTW, I am, overall, super happy:



If you look at the right of the frame, there is some green coloration just above the middle, that gradually fades to black as you go up in the frame. That transition is pretty weak, IMHO. You can see what I am calling "banding" there, and that phenomenon gets worse if/when you add contrast to the image. I suspect it would be much easier to avoid these imperfections starting from a RAW file. But I'll see if tweaking Shadow Correction and/or "Contrast Shadow Adjustment" can improve the situation when shooting JPG...
07-09-2016, 12:05 PM   #48
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I shoot Raw+Jpeg for safety.....the Raw files can accept more correction most of the time, if needed. I do find that sometimes the Jpegs are better than my Raw conversions in regard to noise.

Here is the Jpeg

Name:  IMGP1996-800-K1-A.jpg
Views: 236
Size:  410.9 KB

Here is my version of the converted Raw file.....a difference in WB mostly.

Name:  IMGP1996-800-K1.jpg
Views: 235
Size:  411.9 KB

I actually prefer the Jpeg in this instance. The truth is that most of the time the K1 Jpeg file is plenty acceptable. Only if a WB or exposure problem exists is the Raw a necessary factor.


Here is another Jpeg from the K1 I like better than the Raw one I converted.


Regards!

Last edited by Rupert; 07-09-2016 at 12:37 PM.
07-09-2016, 01:04 PM   #49
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QuoteOriginally posted by Doundounba Quote
None taken. But for me, over 90% of the time I'm just using Levels, Curves, Brightness/Contrast, Heal and/or Clone (for sensor dust) and Crop. It's not rocket science, and for this GIMP works well enough, especially for the price. (I do agree, however, that GIMP is not great to, for example, correct white balance.)



Indeed. On my K-3, the "On" option appears from ISO 200 (it is also absent at ISO125 and 160).

Thanks again! I think this will be helpful to me and I will be playing with these.

BTW, to get a bit more specific, here's an example of my own corner cases, those where I find I have problems with my JPGs. I do a lot of flash macro work. In fact, it's the vast majority of my shooting. Often, that means that in the background there will be some bokeh'ed leaves or other features that gradually fade to black. That's where the (JPG) image is usually the weakest.

Take this shot - with which BTW, I am, overall, super happy:



If you look at the right of the frame, there is some green coloration just above the middle, that gradually fades to black as you go up in the frame. That transition is pretty weak, IMHO. You can see what I am calling "banding" there, and that phenomenon gets worse if/when you add contrast to the image. I suspect it would be much easier to avoid these imperfections starting from a RAW file. But I'll see if tweaking Shadow Correction and/or "Contrast Shadow Adjustment" can improve the situation when shooting JPG...
+ one for GIMP. It is a brilliant editor that certainly requires a learning curve and it is my editor of choice. But that banding you are describing is a classic example of the dreaded 8bit limitation of Gimp processing. And yes it happens when the contrast is pumped esp after previous colour manipulations. Once you understand it it is easy to control. 8 bit processing makes Gimp the nimble beast it is.
https://www.pentaxforums.com/forums/32-digital-processing-software-printing/2...imitation.html

07-09-2016, 01:16 PM   #50
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QuoteOriginally posted by GUB Quote
+ one for GIMP. It is a brilliant editor that certainly requires a learning curve and it is my editor of choice. But that banding you are describing is a classic example of the dreaded 8bit limitation of Gimp processing. And yes it happens when the contrast is pumped esp after previous colour manipulations. Once you understand it it is easy to control. 8 bit processing makes Gimp the nimble beast it is.
https://www.pentaxforums.com/forums/32-digital-processing-software-printing/2...imitation.html
Well this is also the main problem of JPEG. There the compression artefacts, but honestly with a high quality setting you never see it. But while JPEG 2000 support any bit deph it is not much used.

Even if you use GIMP 16 bit version when it is ready, if the source image is 8 bit, like all jpegs produced by cameras, the problem is still here.
07-09-2016, 01:25 PM   #51
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QuoteOriginally posted by GUB Quote
+ one for GIMP. It is a brilliant editor that certainly requires a learning curve and it is my editor of choice. But that banding you are describing is a classic example of the dreaded 8bit limitation of Gimp processing. And yes it happens when the contrast is pumped esp after previous colour manipulations. Once you understand it it is easy to control. 8 bit processing makes Gimp the nimble beast it is.
https://www.pentaxforums.com/forums/32-digital-processing-software-printing/2...imitation.html
Well this is also the main problem of JPEG. There the compression artefacts, but honestly with a high quality setting you never see it. But while JPEG 2000 support any bit deph it is not much used.

Even if you use GIMP 16 bit version when it is ready, if the source image is 8 bit, like all jpegs produced by cameras, the problem is still here. Honestly, I don't know why there isn't an option to produce 16 bit jpegs in camera?
07-09-2016, 02:12 PM   #52
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QuoteOriginally posted by Nicolas06 Quote
Well this is also the main problem of JPEG. There the compression artefacts, but honestly with a high quality setting you never see it. But while JPEG 2000 support any bit deph it is not much used.

Even if you use GIMP 16 bit version when it is ready, if the source image is 8 bit, like all jpegs produced by cameras, the problem is still here.
Actually someone here may be able to answer this - In LR does a jpeg gets processed as 8bit or is it converted to 16 bit for processing?.
07-12-2016, 09:55 PM   #53
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Been working with JPG. Life is too short and my PC has storage issues!!!

We're I to shoot for a wedding or an assignment in challenging light then for sure I'd go RAW.

07-12-2016, 10:53 PM   #54
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QuoteOriginally posted by GUB Quote
Actually someone here may be able to answer this - In LR does a jpeg gets processed as 8bit or is it converted to 16 bit for processing?.
JPEG is 8 bit, you can not get 16 bit from 8. That is why some "features" of Lightroom, CO etc. do not work with JPEG only RAW. When Lightroom works with RAW images it uses all of the data possible and converts to JPEG on export. Converting to JPEG, due to compression, removes data. Those data are not recoverable, it is a one way street using standard JPEG processing. Now with JPEG 2000 and JPEG XR things might be different, but plain old gag you in the throat JPEG throws away data.
07-13-2016, 01:50 AM   #55
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QuoteOriginally posted by PDL Quote
JPEG is 8 bit, you can not get 16 bit from 8
Are you sure about that? I use Digikam for library purposes but it has an editor that I don't use and one of the functions is an 8 -16 bit tool as well as a 16 -8. As I said I havn't used it enough to understand it. But given that it is when you start dragging the histogram around that banding issues kick in it makes sense to be able to do slow 16 bit work and then snap back to 8 for nimbler work. Just to be clear an untampered 8 bit image doesn't have visible banding -- it comes in from careless editting.
07-13-2016, 02:25 AM   #56
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QuoteOriginally posted by GUB Quote
Are you sure about that? I use Digikam for library purposes but it has an editor that I don't use and one of the functions is an 8 -16 bit tool as well as a 16 -8. As I said I havn't used it enough to understand it. But given that it is when you start dragging the histogram around that banding issues kick in it makes sense to be able to do slow 16 bit work and then snap back to 8 for nimbler work. Just to be clear an untampered 8 bit image doesn't have visible banding -- it comes in from careless editting.
Lightroom is a non-destructive editor . That is to say, you can do whatever changes to your RAW files and until you export them there has been no change to the actual RAW file. You can choose what type file you export as, but PDL is right that jpeg is by definition an 8 bit file type. There are plenty of other file types that can have more color depth.

As to converting an image from 8 bits to 16 bits, I'd say that is just a function that changes the container a file is in. Something like pouring a liter bottle into a two liter bottle. What you have doesn't change, but the container changes. Which means that you have the same limitations that you have with a normal jpeg image.
07-13-2016, 04:24 AM   #57
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QuoteOriginally posted by PDL Quote
JPEG is 8 bit, you can not get 16 bit from 8. That is why some "features" of Lightroom, CO etc. do not work with JPEG only RAW. When Lightroom works with RAW images it uses all of the data possible and converts to JPEG on export. Converting to JPEG, due to compression, removes data. Those data are not recoverable, it is a one way street using standard JPEG processing. Now with JPEG 2000 and JPEG XR things might be different, but plain old gag you in the throat JPEG throws away data.
You can't get 16bit from 8 that 100% sure. You'd get still a bit of benefit as intermediate computation would not reduce even more quality.

But the latest JPEG standard (JPEG 2000) that is already quite old allow for 16 and 32 bit floating point so significantly higher quality than what you have in current raw format (12-16 bit integer values). But I get it that it is not really used. If anyway everybody still to the old 8 bit implementation your are stuck.
07-13-2016, 05:30 AM   #58
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QuoteOriginally posted by GUB Quote
Are you sure about that? I use Digikam for library purposes but it has an editor that I don't use and one of the functions is an 8 -16 bit tool as well as a 16 -8. As I said I havn't used it enough to understand it. But given that it is when you start dragging the histogram around that banding issues kick in it makes sense to be able to do slow 16 bit work and then snap back to 8 for nimbler work. Just to be clear an untampered 8 bit image doesn't have visible banding -- it comes in from careless editting.
You can convert from an 8-bit jpeg to a 16-bit tiff (or other 16-bit capable format). But it doesn't really help with your image quality or post processing malleability. Photoshop uses a pretty straightforward linear scaling to go from 8-bit up to its 16-bit format and back to 8-bit so you're not going to get any benefit from converting back and forth between the two during your processing .

You could convert to 16-bits if you had some 8-bit images that you wanted to merge with 16-bit images while maintaining the full data set of the latter files. Or if there are tools that only work on 16-bit images that you want to use. But there's no creating the missing information.
07-24-2016, 01:16 PM - 1 Like   #59
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99.99% of world's JPGs are 8-bit DCT encoded pictures and rest are progressive. JPEG has extended version which makes possible to progressively load the image.

The eight bits aren't those familiar eight bits which everyone is so used to. Those are coefficients for cosine function. Now consider the cosine function to output 16 bits which is more accurate representation of the data and allows next processing stage to use those extra bits more efficiently. And every pixel has output touched by many cosine functions. It is the encoder's choice to select quantification coefficients so that image looks good. One trick In JPEG encoders do is they zero the coefficients in high frequencies. Something low as 10 of 64 coefficients makes good enough image.

Any decent image editor should use some internal representation which allows manipulations work with wide enough values. And I believe they all do that. And as stated previously, missing information cannot be restored.

Here are two videos about JPEG which show how the JPEG works.
07-26-2016, 03:36 AM   #60
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QuoteOriginally posted by anemone Quote
*snip*
*videos*
...that accent!
It was a pain to understand what he meant to say with some phonemes (two pies is better than one , half-man encoding , minus twentytwee etc...) but it was interesting and informative (and clearly expounded).
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