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08-08-2015, 08:02 AM   #1
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LCD image vs actual RAW image

Greetings

I have one question about difference in back of the camera LCD image and actual RAW image on computer.

I'm shooting RAW only, and using both sRGB on my PC (adobe photoshop camera raw) and in my camera and I am not talking about color difference, I am ok with that

Problem is that I even see red clipping highlights on LCD image review and when I get it to my computer, there is no clipping at all. I used natural picture setting in my camera (I know it's for LCD review only) do I need to change that setting to default (bright) or something else, or is the histogram only thing that i should look while reviewing my images on LCD camera screen?

Thank you

08-08-2015, 08:22 AM   #2
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QuoteOriginally posted by panicAttack Quote
the histogram only thing that i should look while reviewing my images on LCD camera screen?
That's the approach I take.
08-08-2015, 08:31 AM   #3
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I have the clipping flashers turned on in my camera as well - it gives a clue as to where you will be near clipping in RAW. The LCD is an extracted JPEG. As long as you don't have the whole sky flashing, and only some bits of a cloud flash, or only speckles in the water foaming at a water fall, it will be just fine.

The black side clipping is useful for the same thing. In really tricky situations, I will see the clipping, turn on the histogram, and if it looks close, and I have the time to do it, I will use a variation of the zone system. Spot meter the brightest area you want to keep detail and add 2 stops. The obverse is to meter the darkest area you want to keep detail in and subtract 2s stops. Some prefer 1.5 stops. With the metering balance on the K10D, which, as with most Pentax cameras, meters for slide film (-0.5 stops or so) to avoid blowing out the highlights I will sometimes go +2.0 for bright metering and -1.5 for dark metering. I find that to be a bit of overkill, though. Even with 12 bit RAW like the K10D, there is a lot of wiggle room on exposure.
08-08-2015, 09:51 AM   #4
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The rear LCD displays the preview JPEG embedded in the RAW file. As such it reflects the JPEG settings you have chosen. As a result, the histogram may not represent the actual state of the data in the file. Use the in-camera histogram and clipping alerts as a guide, not as boundary. BTW, it helps to have the JPEG set to natural or something similar to the import profile for your RAW converter.


Steve

08-09-2015, 12:45 AM   #5
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QuoteOriginally posted by johnyates Quote
That's the approach I take.
Does histogram represent jpeg or raw data?
08-09-2015, 05:02 AM   #6
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QuoteOriginally posted by panicAttack Quote
Does histogram represent jpeg or raw data?
The histogram belongs to the displayed image that is jpg data - the sensor's raw data isn't RGB data. After the capture you can show all RGB channel histograms of the embedded jpeg image of the raw file - at least when using a K5.

Last edited by acoufap; 08-09-2015 at 05:09 AM.
08-09-2015, 08:03 AM   #7
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QuoteOriginally posted by acoufap Quote
The histogram belongs to the displayed image that is jpg data - the sensor's raw data isn't RGB data. After the capture you can show all RGB channel histograms of the embedded jpeg image of the raw file - at least when using a K5.
The K10 can display all four histograms on the LCD, but they are all based on the extracted JPEG image.
08-09-2015, 09:00 AM   #8
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QuoteOriginally posted by Canada_Rockies Quote
The K10 can display all four histograms on the LCD, but they are all based on the extracted JPEG image.
Same as K5. The general brightness histogram is also shown. Would be a nice add on to have the option to display the RGB histograms while beeing in live view mode. In this mode only the brightness histogram can be shown.

08-09-2015, 09:01 AM   #9
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QuoteOriginally posted by acoufap Quote
The histogram belongs to the displayed image that is jpg data - the sensor's raw data isn't RGB data. After the capture you can show all RGB channel histograms of the embedded jpeg image of the raw file - at least when using a K5.


it can show all channels, but the problem is that it is completely different after saving image on computer and opening it in ACR. (Adobe camera raw)

and i am talking about exposure, it's normal for colors to be slightly different even I use sRGB on both pc and camera.
08-09-2015, 09:20 AM   #10
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QuoteOriginally posted by panicAttack Quote
it can show all channels, but the problem is that it is completely different after saving image on computer and opening it in ACR. (Adobe camera raw)

and i am talking about exposure, it's normal for colors to be slightly different even I use sRGB on both pc and camera.
No surprise in my opinion. ACR doesn't know the color profile you have set in camera (natural, bright, portrait, monochrome, ... whatever). ACR uses a profile that is associated as standard for your camera type while converting raw data to a rgb representation. By example although using in camera monochrome profile you'll see that ACR will generate a color version. The difference between the in camera generated jpg and the ACR version is instantly obvious. This doesn't mean that one of these "color interpretations" and their associated histograms are wrong.

Last edited by acoufap; 08-09-2015 at 09:27 AM.
08-09-2015, 09:27 AM   #11
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QuoteOriginally posted by acoufap Quote
No surprise in my opinion. ACR doesn't know the color profile you have set in camera (natural, bright, portrait, monochrome, ... whatever). ACR uses a profile that is associated as standard for your camera type. By example although using in camera monochrome profile you'll see that ACR will generate a color version. The difference between the in camera generated jpg and the ACR is instantly obvious. This doesn't mean that one of these "color interpretations" and their associated histograms are wrong.
I know none is wrong, but it is hard when you see few of your images looks slightly overexposed on your camera (clipping highlights), turn down exposure for stop or two, then shot hundreds more and when you transfer your files to computer then realise that only those frist overexposed images were right exposed and all others are completely underexposed.

That's huge problem, but i will get used to that.

---------- Post added 08-09-15 at 10:05 AM ----------

QuoteOriginally posted by acoufap Quote
Some of the in camera profiles push the brightness of specific colors so the histogram shows blown highlights although there is some "headroom". Maybe it helps a bit if you set the natural profile.
it was. i wrote that on the first comment
08-09-2015, 10:13 AM   #12
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QuoteOriginally posted by panicAttack Quote
That's huge problem, but i will get used to that.
It's a matter of time and carefully comparing the in-camera histogram to the results in your raw converter. Keep your jpeg settings constant and make note of what the in-camera histogram looks like for the exposures that are 'good' on your computer, you'll eventually learn to compensate.

Alternatively, you could do your metering off of a gray card or get an incident light meter. Both will require some calibration to get exposures you want, but make it much easier to consistently repeat results you're happy with.
08-09-2015, 10:29 AM   #13
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QuoteOriginally posted by panicAttack Quote
I know none is wrong, but it is hard when you see few of your images looks slightly overexposed on your camera (clipping highlights), turn down exposure for stop or two, then shot hundreds more and when you transfer your files to computer then realise that only those frist overexposed images were right exposed and all others are completely underexposed.

That's huge problem, but i will get used to that.

---------- Post added 08-09-15 at 10:05 AM ----------



it was. i wrote that on the first comment
I deleted my last comment, because I saw it afterwards - sorry.

I think there's no way to get a precise histogram in camera for all situations that may occur. But you could try to find out the headroom that's availlabe. Just an idea. Never did it by myself.

Do an ETTR (expose to the right) capture of a scene with constant (contolled) light (best done with camera on tripod). Then do some more captures of the same scene. With every capture increase the exposure time by 1/3 ev. Load all the images into ACR. One of the last images should show blown out highlights.
How many 1/3 ev steps did you measure before you got blown highlights? That should be the "headroom" of your specific camera. You can use this for controlled overexposure - if you like and if you want to take the risk.
08-10-2015, 01:31 PM   #14
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QuoteOriginally posted by acoufap Quote
I deleted my last comment, because I saw it afterwards - sorry.

I think there's no way to get a precise histogram in camera for all situations that may occur. But you could try to find out the headroom that's availlabe. Just an idea. Never did it by myself.

Do an ETTR (expose to the right) capture of a scene with constant (contolled) light (best done with camera on tripod). Then do some more captures of the same scene. With every capture increase the exposure time by 1/3 ev. Load all the images into ACR. One of the last images should show blown out highlights.
How many 1/3 ev steps did you measure before you got blown highlights? That should be the "headroom" of your specific camera. You can use this for controlled overexposure - if you like and if you want to take the risk.
Over time I found that +0.3 to +1.0 is a good, easy range for exposing to the right. Capture One can recover lost highlights through a combination of highlight recovery and negative exposure compensation in software. Colors and contrast are still good and noise goes down with the negative exposure compensation in software.

The exact value will depend a lot on the scene and how the exposure meter registers the light. Sometimes +0.3 is good. Sometimes +1 is good.
08-10-2015, 01:56 PM   #15
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QuoteOriginally posted by panicAttack Quote
Does histogram represent jpeg or raw data?
QuoteOriginally posted by stevebrot Quote
The rear LCD displays the preview JPEG embedded in the RAW file...
...the rest of the post tells how. For convenience, here is a summary of the helpful advice in the comments above:
  • On playback, the rear LCD displays a JPEG thumbnail extracted from embedded data in the actual image file. This is separate and different from the actual image.
  • The JPEG is the same regardless of whether the file is JPEG or RAW
  • The JPEG reflects the custom image settings in affect at time of capture. This is true for both JPEG and RAW.
  • The display histogram is derived from the displayed JPEG and reflects the custom image setting at time of capture
  • RAW files have no histograms per se. Histograms may be built from the RAW data, but only after they have been interpreted for display.
  • You can use the histogram display on the camera as a guideline for exposure tuning, but it may or may not correspond directly to the histogram displayed by tools such as Adobe Lightroom.


Steve

Last edited by stevebrot; 08-10-2015 at 02:12 PM.
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