Histograms and Raw

[ChuckZ]

Per a posting I read somewhere recently, they said that even if you are shooting raw, the camera histogram is based on the result you would get if you are shooting jpg.  They went on to say that you should setup your camera for the color space with the widest gamut (AdobeRGB for my D300) and set the contrast at a minimum (in Set Picture Control in D300) to get a histogram that most closely represents the raw image.  I just returned from Death Valley and am currently processing the shots.  Surely enough, while the histogram in Lightroom is not exactly what I see on the camera display, it is pretty close and definitly closer than when I was using the camera defaults.

[lovell]

Per a posting I read somewhere recently, they said that even if you are shooting raw, the camera histogram is based on the result you would get if you are shooting jpg.  They went on to say that you should setup your camera for the color space with the widest gamut (AdobeRGB for my D300) and set the contrast at a minimum (in Set Picture Control in D300) to get a histogram that most closely represents the raw image.  I just returned from Death Valley and am currently processing the shots.  Surely enough, while the histogram in Lightroom is not exactly what I see on the camera display, it is pretty close and definitly closer than when I was using the camera defaults.

1. Raw images have no color space.
2. Yes, when shooting raw, the jpg on the back of camera is what the histo is based on, and this jpg reflects the set up parameters you chose.
3. However, the actual raw image has no color space, nor will it necessarily reflect the look of the corresponding jpg.
4. Raw's will have a bit wider DR, so what looks blocked of blown on the jpg, may not necssarily be the case for the raw file.
5. I would nutralize/turn off all jpg effects so that it looks closer to how the corresponding raw looks.
6. You can set the camera to any color space you want, but the raw has no color space, so it don't matter.

[dwdallam]

I leave my 1DS MKIII in all neutral or "standard" and the histogram is very close in all ways.

[Wayne Fox]

1. Raw images have no color space.
2. Yes, when shooting raw, the jpg on the back of camera is what the histo is based on, and this jpg reflects the set up parameters you chose.
3. However, the actual raw image has no color space, nor will it necessarily reflect the look of the corresponding jpg.
4. Raw's will have a bit wider DR, so what looks blocked of blown on the jpg, may not necssarily be the case for the raw file.
5. I would nutralize/turn off all jpg effects so that it looks closer to how the corresponding raw looks.
6. You can set the camera to any color space you want, but the raw has no color space, so it don't matter.

I don't believe anything in the original post implied that the raw has a color space.  What it did say is to offset the effect of #4 in your statement, the OP felt that setting the camera to aRGB and using a preset with low contrast provided a histogram that was closer to what the raw histogram would look like.  I believe many fiddle with the jpeg settings in an effort to achieve this goal. The biggest challenge of using ETTR is knowing when you are actually clipping the raw data.

[bjanes]

1. Raw images have no color space.

That assertion is questionable. Thomas Knoll and other experts do regard raw files as having a color space.

See this thread  for a spirited discussion on this topic.

[tokengirl]

I also now have my 5DII set to Neutral, with the contrast as low as possible and the colorspace set to aRGB.  BIG IMPROVEMENT!  It doesn't affect the RAW file in any way, shape or form, but what it does do is give you a camera histogram that shows a much more accurate representation of how much latitude you have.  When I had the contrast setting at the default setting, the histogram would frequently show blown highlights when there weren't any.  Which, of course, led me to underexpose unnecessarily.

Good exposure is critical.  These settings really do help ensure it.

[Guillermo Luijk]

If you want your camera's histogram become as close as possible to the RAW data, all those tricks you mention have much less effect than neutralising the camera white balance, which is the main difference between JPEG and RAW exposure.

More info in this thread: Camera's histogram reliable to the RAW data and in this article: UNIWB. MAKE CAMERA DISPLAY RALIABLE.

The article appeared some weeks ago in LL was a bit surprising to me, it seems Michael doesn't look too carefully at the discusions hold in his own forum (I know I know, you are very busy Michael).

Regards

[lovell]

I don't believe anything in the original post implied that the raw has a color space.  What it did say is to offset the effect of #4 in your statement, the OP felt that setting the camera to aRGB and using a preset with low contrast provided a histogram that was closer to what the raw histogram would look like.  I believe many fiddle with the jpeg settings in an effort to achieve this goal. The biggest challenge of using ETTR is knowing when you are actually clipping the raw data.

Read the OP's initial post again...the implication that raw has a color space is there.

I think it would be best for him to nuetralize all effects that effect the jpg so that the resulting histogram on the back will more closely match the corresponding raw image.

[lovell]

That assertion is questionable. Thomas Knoll and other experts do regard raw files as having a color space.

See this thread  for a spirited discussion on this topic.

I read that thread, and I will continue to maintain that raw files do not in fact have color space.  

A raw image is just that.  Raw, lacking post processing by the camera.  

A color space is just a multi-plier (or shift) to the digital data during conversion in PhotoShop (or other processing program).

You can shoot in all the color spaces your camera provides, but doing so will not change the actual digital raw data when shooting the same exact composition for each color space.

That thread starts off asserting that a raw image is not color.  This is not true.  If that were true then by that flawed logic, jpg files are not color either.

All digital pictures provide digital values that represent the three primary colors, and mixtures of them.

Just because someone wrote a book should not guarentee they know what they're talking about.

Raw has no color space.

[JeffKohn]

Read the OP's initial post again...the implication that raw has a color space is there.

No, it isn't.  I don't think  you understood what he wrote. Most cameras have an option for color space selection, and he mentioned setting it to Adobe RGB. He never said anything about it affecting the RAW data, what he said was that the in-camera histogram now better reflects the RAW data. And this is true, because the in-camera colorspace setting affect JPEG's, and the in-camera histogram is based on the camera's JPEG engine and the processing it does.

[Panopeeper]

I will continue to maintain that raw files do not in fact have color space.  

A raw image is just that.  Raw, lacking post processing by the camera

Yes, it is raw, more or less, depending on the camera and options). What exactly does that have to do with color space?

A color space is just a multi-plier (or shift) to the digital data during conversion in PhotoShop (or other processing program)

This is not so, though it describes one possible way of the white balance application.

You can shoot in all the color spaces your camera provides, but doing so will not change the actual digital raw data when shooting the same exact composition for each color space

That's right. The color space is always the same, namely the color space of that camera.

That thread starts off asserting that a raw image is not color

The raw image IS color, but not RGB.

All digital pictures provide digital values that represent the three primary colors, and mixtures of them

This is incorrect. Examples: CMYK, Lab, and raw images.

Raw has no color space

I'm afraid you need some more effort to explain, why not.

[Ben Rubinstein]

If you want your camera's histogram become as close as possible to the RAW data, all those tricks you mention have much less effect than neutralising the camera white balance, which is the main difference between JPEG and RAW exposure.

More info in this thread: Camera's histogram reliable to the RAW data and in this article: UNIWB. MAKE CAMERA DISPLAY RALIABLE.

The article appeared some weeks ago in LL was a bit surprising to me, it seems Michael doesn't look too carefully at the discusions hold in his own forum (I know I know, you are very busy Michael).

Regards

Question about the method detailed in the above article. From what I understand from a practical point of view you need to take the file and load it up into the camera as a custom WB using the usual method. This does mean of course that the file needs to be on each and every card (replaced after every format) and you would have to reload the custom WB from the card every time you put a new card in. As most pro's do not use just one large card (I shoot weddings with multiple  smaller cards) nor do they have time to replace a file after every format or remember to upload it to the camera system, I would suggest that practically this method might work best with a 1 series where the SD card slot is either not used (the file can reside there permenantly) or where a large SD card acts as backup to the main card which would be used more frequently thereby having the file remain available to the camera throughout a long shooting session even when the main card is being replaced frequently.

I'm going to try the generated file on my 5D, question before I begin, often in cases when using severe filtration the correction available in ACR or C1 is limited. I have files all shot under a blue awning which are impossible to correct sufficiently. Heck even not having the ability to change the WB +/- 1500K could be a real problem in real world use. Do you find that to be an issue using this custom WB image you've invented?

Many thanks

[Guillermo Luijk]

you need to take the file and load it up into the camera as a custom WB using the usual method. This does mean of course that the file needs to be on each and every card

No, you just need to load that particular WB on your custom WB bank in the camera. After that the file can be deleted from the card, and the UniWB can be used no matter which card you are using just by selecting that custom WB.

Anyway I think UniWB is perhaps not the best method for a wedding photographer. You are using controlled lighting (flash) and you need to be very quick so there is no time for perfect ETTR. Also perhaps some of the guests want to see the images straight from your camera and the green tint can be confusing.

I'm going to try the generated file on my 5D, question before I begin, often in cases when using severe filtration the correction available in ACR or C1 is limited. I have files all shot under a blue awning which are impossible to correct sufficiently. Heck even not having the ability to change the WB +/- 1500K could be a real problem in real world use. Do you find that to be an issue using this custom WB image you've invented?

No, the UniWB is irrelevant at RAW development time, it is just a _capture_ time trick. It doesn't alter in any way the RAW data produced, only the WB metadata. You are not filtering the image at all.

I.e. if you shoot a scene at 1/200@f/8 with UniWB and next with the Daylight WB preset, the RAW data will be _exactly_ the same. Your image will open green in ACR just because the RAW developer tries to mimic that 'strange' WB you applied on the camera, but as soon as you set ACR's Tungsten WB the resulting image will be undistinguishable from the shot done with the Daylight preset once Tungesten is set in ACR. Try it.

Regards

[bjanes]

I read that thread, and I will continue to maintain that raw files do not in fact have color space.  

That thread starts off asserting that a raw image is not color.  This is not true.  If that were true then by that flawed logic, jpg files are not color either.

All digital pictures provide digital values that represent the three primary colors, and mixtures of them.

Just because someone wrote a book should not guarentee they know what they're talking about.

Raw has no color space.

Lovel,

You need to read and think critically before engaging your mouth. No way did the OP suggest that the file had a color space. He merely pointed out that one had the option of rendering the raw files into various color spaces supported by the camera's JPEG engine.

The thread you referenced did start off suggesting that the raw file contained color information, the same as an sRGB rendered image. Others maintained that the raw was monochrome and not color. Color itself is a perception that takes place in the eye and brain. The camera merely records tristimulus information that relates to color.

You sum up by reiterating without supporting facts or reasoning that raw has no color space and denigrating authors of unnamed books. Since your thinking is rambling, noncritical, and unsupported by any reasoning or factual data, I could care less whether you consider that raw has a color space or not.

[Ben Rubinstein]

No, you just need to load that particular WB on your custom WB bank in the camera. After that the file can be deleted from the card, and the UniWB can be used no matter which card you are using just by selecting that custom WB.

Anyway I think UniWB is perhaps not the best method for a wedding photographer. You are using controlled lighting (flash) and you need to be very quick so there is no time for perfect ETTR. Also perhaps some of the guests want to see the images straight from your camera and the green tint can be confusing.



No, the UniWB is irrelevant at RAW development time, it is just a _capture_ time trick. It doesn't alter in any way the RAW data produced, only the WB metadata. You are not filtering the image at all.

I.e. if you shoot a scene at 1/200@f/8 with UniWB and next with the Daylight WB preset, the RAW data will be _exactly_ the same. Your image will open green in ACR just because the RAW developer tries to mimic that 'strange' WB you applied on the camera, but as soon as you set ACR's Tungsten WB the resulting image will be undistinguishable from the shot done with the Daylight preset once Tungesten is set in ACR. Try it.

Regards

My bad, I didn't realise the camera retained the data indefinately as the custom WB, I thought it had to have the file to reference otherwise it would disappear. Does make life easier.

I've personally always calibrated the jpg preview (and by definition the histo) to match my ACR defaults. Gives me a better idea of what I have. I don't specifically shoot ETTR at weddings though although I tend towards hot rather than underexposed these days given the amount of information I can trust ACR to retain in the dresses, using the dodge and burn tools, etc. Didn't used to be like that in the older raw converter days when you held the whites in camera and tried to ignore the noise as you pulled the faces back up.

I did some trial shots, the histogram still looked nothing like the one in ACR and I couldn't see what was going on with the screen as well, bit confusing. Is there a specific colour space I need to use? Will the histo only match ProPhoto and 16 bit for example? That would be useless for me, I work in srgb and 8 bit because that is what my output space and depth is. Haven't got time when processing hundreds of images for the lab for colourshifts or suprise blown highlights when I convert down a colour space and bit depth at the end of the processing. As you said, this isn't really for me...

[Guillermo Luijk]

I tend towards hot rather than underexposed these days given the amount of information I can trust ACR to retain in the dresses

This is a common mistake. ACR (or any RAW developer) doesn't retain any information, it just displays the information present in the RAW file. There is no merit at all in doing that. The general belief is that RAW can help us to _recover_ information. Recover? where and when was that information lost that we have to recover it now?.

RAW doesn't recover anything, it was camera's JPEG that eliminated a lot of information from the RAW, specially highlights information and basically because of the white balance process. Opening the RAW file in a RAW developer doesn't mean recovering anything, it just means _not losing_ what it was lost when the camera built the JPEG file.

That is why UniWB makes sense: until camera manufacturers take into account RAW shooters, and decide to help us providing tools that allow to know how good resulted the data collected in the RAW file (for example providing RAW histograms in the camera, instead of cooked overexposed JPEG histograms), UniWB can help to make camera histograms get closer (never exactly the same) to a RAW histogram.

I did some trial shots, the histogram still looked nothing like the one in ACR and I couldn't see what was going on with the screen as well, bit confusing.

You seem to be believing the ACR histogram is the RAW histogram. It is not, ACR's histogram is a cooked version of the RAW histogram, i.e. a cooked version of what you really have in the RAW file. Among others the processes of white balance, colour interpolation and output colour profile conversion took place. The good thing of ACR is that it allows you to set a negative exposure compensation that brings again to life all that information that the white balance (which is a positive exposure compensation for each indivigual RGB channel) was blowing.

So ACR is OK to find out how much information the RAW file really has, but still it is not a RAW histogram. So don't expect camera's histogram + UniWB be close to what you will see in ACR. The goal of UniWB is to make camera's histogram closer to a genuine RAW histogram.

[Panopeeper]

This does mean of course that the file needs to be on each and every card (replaced after every format) and you would have to reload the custom WB from the card every time you put a new card in

This is a different issue, but

1. one can make a file read-only on the card,

2. there is no reason to format the card every time, erase all is good enough - and this does not delete the read only files.

Thus the WB template image can remain on the card for ever. This is how I am doing it, though I have to admit, that I don't really need it, for I always use that WB template.

[feppe]

2. there is no reason to format the card every time, erase all is good enough - and this does not delete the read only files.

While technically true, (quick) format takes one second on Canon cameras, but delete all images takes a lot longer.

Also, after long use file fragmentation might become a problem and impact write/read speeds, but I have a feeling that is might be mostly an academic problem on flash cards.

[Ellis Vener]

Per a posting I read somewhere recently, they said that even if you are shooting raw, the camera histogram is based on the result you would get if you are shooting jpg.  They went on to say that you should setup your camera for the color space with the widest gamut (AdobeRGB for my D300) and set the contrast at a minimum (in Set Picture Control in D300) to get a histogram that most closely represents the raw image.  I just returned from Death Valley and am currently processing the shots.  Surely enough, while the histogram in Lightroom is not exactly what I see on the camera display, it is pretty close and definitely closer than when I was using the camera defaults.

ChuckZ,

Rather in engage in the theocratic argument other members are having  I just want to point out that you are correct in what you are doing and seeing.

[Panopeeper]

Rather in engage in the theocratic argument other members are having  I just want to point out that you are correct in what you are doing and seeing.

As I too have posted in this thread, I feel shocked by your assessment, that the argumentation here is theocratic. Aside from that, ChuckZ has thoroughly misunderstood the entire subject (like you did), because his intention was to see a histogram that most closely represents the raw image; but what he sees in Lightroom is the histogram of the JPEG image created by either the camera or by LR.

Anyway, Happy Christmas.