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05-17-2019, 05:55 AM - 1 Like   #61
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QuoteOriginally posted by GUB Quote
Isn't it just simpler , once you start working in raw, to leave your camera jpg settings in a standardised state and gain a sense of what you can get away with with experience. One glance at the editor raw histo to see if the right hand end of the data is spiked and sawn off is all you need to check --- it doesn't need to get more complicated than that.
Easier maybe and yes experience will count. But if you wish to aim for optimal probably best to investigate a little more to understand what is happening at each stage of workflow.

Bottom line is that most of the time you will get perfectly acceptable images just accepting what the meter and the raw editor shows you. But be aware that you are not seeing the truth just someone elses interpretation rendering your raw data to look good, just the same as the camera manufacturers comittee have decided how raw images should be rendered and the variations they may offer in camera presets.

An example already posted of an underexposed image of how it looked OK in the raw editor (and similar on camera screen). Truth is that this image under exposed probably around -2 2/3 EV compared to an optimally exposed image and losing nearly 3 stops DR and an increase in noise characteristic. In this case I could not care less but in other circumstances it may have helped to understand and attempt to get things right in camera

1. JPEG in camera settings obviously affect JPEG only but include the look and histogram seen on the camera LCD - maybe helpful or not as once you observe clipping then you have more headroom in the raw data, probably over +1EV.

2. If you are using your camera histogram to try and see close to raw you could use UniWB (if you can stomach the green look) or set the lowest contrast an most neutral picture settings for JPEG to get closer to clipping point

3. Find out your own camera clipping point for metering with some practical tests. Spot metering being easiest. Spot read an area containing texture and make a series of exposures based 0.3EV apart. As it is likely your meter calibrated around 12.5% (about +3EV from sensor saturation) you may want ot start at +2 1/3EV and increase up to +3 2/3 EV. Once you have found the point of saturation in the field (assume you found +3EV) you will know when you meter a specific ROI then you can apply up to +3EV without clipping and still retain texture. Now in the unlikely event that your camera meter is calibrated to 18% the theoretical point of saturation will be +2.47EV from meter suggestion (spot or possibly centre weighted are the best candidates for this)

4. You will not see a raw histogram in most image editors. So unless you evaluate using similar to RawDIgger or change your editors processing to mimic as shown above your really do not know what your data represents, other than in most cases and adjustment to make a pleasing first rendition that will need further editing to taste.


Last edited by TonyW; 05-17-2019 at 06:14 AM.
05-19-2019, 11:53 PM   #62
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QuoteOriginally posted by GUB Quote
So in other words you are careful not to over-expose the shot !
Basically yes, but the problem lies with finding out what is overexposed.
And the main point is that it take a lot to clip reds in outdoor light, if your whites that are being lite the same as your red subjects and the whites are not clipped then your reds are not also.

---------- Post added 05-20-2019 at 12:04 AM ----------

QuoteOriginally posted by GUB Quote
One glance at the editor raw histo to see if the right hand end of the data is spiked and sawn off is all you need to check --- it doesn't need to get more complicated than that.
Yes but just like Tony has stated, without setting up the raw converter to show you a more accurate representation of what unprocessed raw data looks like its hard to know what to base what you can recover and what you have.

One of the problem with the red is that they are in themselves underexposed most of the time and using the method of underexposing them to recover what you may think is lost only adds to the problem your already have and is why you see less detail and worse recorded color in the red's.
05-20-2019, 02:10 AM   #63
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For most consumers using Lightroom the first and easy step for these situations is to grab the "primary red" color slider at the lower end of the right hand pane in LR where you choose DNG camera profiles.

I expect you are able to fix 9 out of 10 "red problems" caused by the raw converts processing that way in a few seconds with no need to change other parts of your workflow.
Only if that does not work I'd start looking at the more complex options.
05-20-2019, 02:35 AM   #64
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QuoteOriginally posted by beholder3 Quote
to grab the "primary red" color slider at the lower end of the right hand pane in LR where you choose DNG camera profiles.
I don't do LR but if that slider is to lower red saturation then you are leaving yourself open to a colour cast in the rest of the image if you apply it globally.
But the main thing to emphasise is if it has been over-exposed / clipped in the camera then no amount of PP work can correct it.

05-20-2019, 05:14 AM   #65
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QuoteOriginally posted by GUB Quote
I don't do LR but if that slider is to lower red saturation then you are leaving yourself open to a colour cast in the rest of the image if you apply it globally.
But the main thing to emphasise is if it has been over-exposed / clipped in the camera then no amount of PP work can correct it.
It is possible that lowering the red primary saturation or even hue will not necessarily open a colour cast in the rest of the image as it is primarily 'correcting' an over enthusiastic interpretation of red which may include areas outside of the ROI, albeit much less affected.
My preference however would be to go directly to the HSL/Colour tab in ACR and LR where you can individually adjust all parameters for Red, Orange, Yellow, Green, Aqua, Blue, Purple and Magenta. Using this method appears to limit the affect to just the selected colour without too much change to other areas globally. You can even use this method in PS with the advantage of being able to mask precisely where you need to apply changes


While we should all endeavour to get it right in camera, which means expose so no clipping and applying the correct profile that may 'tame' certain colours that need it, we have to accept that sometimes we may miss an unrepeatable shot. But we should not necessarily give up as it is sometimes possible to recover an image that is clipped in one channel by applying some post work in an image editor (not a raw converter). If there are at least two good channels of information then even a raw converter can do quite a lot, however there is a limit. An application like PS may be able to combine/refine/repair channels that are clipped with a little work

For example and I hope the OP does not mind taking his red flower image (not overexposed imo) even though JPEG the reds can be tamed to allow some detail to be brought back - just an interpretation and proof of concept rather than a good example
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Last edited by TonyW; 05-20-2019 at 06:04 AM. Reason: Forgot to mention HSL sliders
05-20-2019, 06:08 AM - 1 Like   #66
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QuoteOriginally posted by GUB Quote
I don't do LR but if that slider is to lower red saturation then you are leaving yourself open to a colour cast in the rest of the image if you apply it globally.
But the main thing to emphasise is if it has been over-exposed / clipped in the camera then no amount of PP work can correct it.
The typical issue discussed here is a global "wrong" processing applied by the raw converter to all reds that is just being corrected, so quite often you will not end up with any color casts by doing this.
But I will not say that in some cases this won't happen.
My recommendation ist just to try this simple thing before investing more time.
05-20-2019, 08:47 AM   #67
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QuoteOriginally posted by Ian Stuart Forsyth Quote
Basically yes, but the problem lies with finding out what is overexposed.
Therein is the value of placing exposure rather than attempting to anticipate exposure. I admit to generally doing the latter, but good results in many situations demand the former.

QuoteOriginally posted by Ian Stuart Forsyth Quote
And the main point is that it take a lot to clip reds in outdoor light, if your whites that are being lite the same as your red subjects and the whites are not clipped then your reds are not also.
It depends on your subject and how you are metering. I have not posted my rawdigger graphs yet, but it only took me the time to walk out the door and snap a single frame of a sunlit red rhododendron bloom using matrix metering on my K-3. Bam! Clipped reds in the RAW.


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05-20-2019, 08:52 AM   #68
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QuoteOriginally posted by beholder3 Quote
For most consumers using Lightroom the first and easy step for these situations is to grab the "primary red" color slider at the lower end of the right hand pane in LR where you choose DNG camera profiles.
That works fine, assuming LR has some headroom to work with. Its histograms and highlight alerts are a bit deceptive in that they will alert clipping well below where such actually exists in the capture data and it is usually possible to have ACR back off from where it was blocking up detail.


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05-20-2019, 08:54 AM   #69
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QuoteOriginally posted by GUB Quote
But the main thing to emphasise is if it has been over-exposed / clipped in the camera then no amount of PP work can correct it.
This ^ ^ ^

Where no numbers exist to express the light, no expression will be made.


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05-20-2019, 08:58 AM   #70
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QuoteOriginally posted by TonyW Quote
It is possible that lowering the red primary saturation or even hue will not necessarily open a colour cast in the rest of the image as it is primarily 'correcting' an over enthusiastic interpretation of red which may include areas outside of the ROI, albeit much less affected.
Sometimes, yes, but red is ubiquitous in many images, particularly in foliage. Masking to do the adjustment is often needed, if indeed that works at all.


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05-20-2019, 09:00 AM - 1 Like   #71
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You guys make this all so complicated. Set up your tripod and use the bracket function. Pick the best red in post if it's important. You guys sound like you're using film and trying to save money on film. Those exposures cost you a couple of pennies each on digital. Five for a dime.

Also, use pixel shift where possible.

Last edited by normhead; 05-20-2019 at 09:16 AM.
05-20-2019, 09:20 AM   #72
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QuoteOriginally posted by normhead Quote
You guys make this all so complicated. Set up your tripod and use the bracket function. Pick the best red in post if it's important. You guys sound like you're using film and trying to save money on film. Those exposures cost you a couple of pennies each on digital. Five for a dime.


The problem comes when one gets home and finds that the full day in the field with the gorgeous red and yellow tulips was a waste due to not being able to properly review in the rear LCD (too bright out) and not knowing that those intense colors are , ummmm, "touchy".

A little later in the season, we find out that the delicate purple in lilacs and irises may or may not be captured to our liking and may not be adjustable to reality either.


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05-20-2019, 09:39 AM   #73
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QuoteOriginally posted by stevebrot Quote


The problem comes when one gets home and finds that the full day in the field with the gorgeous red and yellow tulips was a waste due to not being able to properly review in the rear LCD (too bright out) and not knowing that those intense colors are , ummmm, "touchy".

Steve
Which is why I said bracket and review in post, as in post processing. If you set your bracket steps an appropriate distance apart, you're going to have a good exposure.

I'm not buying which way is more likely to produce lunch bag let down when you get home until someone actually runs a comparative test.

I'm picky that way. I'm more interested in the way it is as compared to people's opinions of what they think the way it is will be.
05-20-2019, 11:31 AM   #74
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QuoteOriginally posted by stevebrot Quote
Sometimes, yes, but red is ubiquitous in many images, particularly in foliage. Masking to do the adjustment is often needed, if indeed that works at all.
Steve
Masking and channel chops works very well but is not infallible and of course cannot be accomplished in a raw editor without the ability to mask and play with channels individually.

This thread has only become complex due to specific questions raised and not getting any answers therefore responses may have been too generalised

I think that anyone viewing this thread outside of Pentax fold may get the impression that there is a fundamental issue with Pentax and reds - I do not think that this is the case but....

As yet I have not seen any signs of overexposure in any posts here (to the point of clipping) on the contrary I have seen some very nice red images (my subjective view of course) without issue (but no indication of exposure)

I have seen comment on reds too red, but that is entirely subjective and rather difficult to judge as there is no indication of how the reds are being viewed e.g. raw editor, editor camera profile, on monitor or print, sRGB or Adobe RGB coverage of monitor and print gamut, calibration state of monitor, or print and what the print settings are, paper type, profile etc.

Entirely possible that you will see clipping indicator on monitor where it will not be on print so view the soft proof with a good paper profile

I have also seen comments about red channel being truly clipped and while I agree recovery may not be possible but as yet no one has offered a raw image to demonstrate the problem and open up avenue to others to explore to see if it can be solved - any one game enough to post a problematical raw?

Last edited by TonyW; 05-20-2019 at 12:17 PM.
05-21-2019, 12:11 AM   #75
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QuoteOriginally posted by stevebrot Quote
It depends on your subject and how you are metering. I have not posted my rawdigger graphs yet, but it only took me the time to walk out the door and snap a single frame of a sunlit red rhododendron bloom using matrix metering on my K-3. Bam! Clipped reds in the RAW.
And if you take a look your whites they will be overexposed well before your reds and that is my point if your whites are not clipped then your red are not unless your are under some kind of artificial light.


here in daylight light I have clipped my whites on purpose and even in to the first grey while nothing in the red and yellow flowers have clipped
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