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In-camera RAW histograms


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As far as I know, there are no cameras available with in-camera RAW histograms. So why is that? How difficult could it be to write the code? After all, code has been created for demosaicing the RAW data and creating jpeg histograms. Why only jpeg? Isn't RAW way more important for the more serious photographer? How fast asleep are the camera manufacturers? I don't get it; do you?
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Care to tell me what I would take away from that?

Re: Why no on camera raw histograms: Beginners Questions Forum: Digital Photography Review

 

"A histogram is a representation of the red, blue and green channels of an image ... which do not exist in those forms until after the RAW data has been processed. Look at the first reply to the similar question here:"

 

RAW images are processed In-camera as JPEG previews, according to your picture style or profile preferences, and used to create a histogram. That begs the question why anyone would prefer one camera over another based on the colors, which have nothing to do with the content of RAW files, only their translation.

Edited by Ed_Ingold
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At least in the case of Canon cameras, the histogram and thumbnail reflect the particular picture style set in the camera. The postprocessing done in the picture style can make the histogram unrepresentative of the raw capture--e.g., it can show clipping when there isn't any. Canons have a picture style ("faithful") that makes minimal adjustments, so if you are shooting raw, that will give you the most informative histogram.
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"A histogram is a representation of the red, blue and green channels of an image ... which do not exist in those forms until after the RAW data has been processed. Look at the first reply to the similar question here:"

 

RAW images are processed In-camera as JPEG previews, according to your picture style or profile preferences, and used to create a histogram. That begs the question why anyone would prefer one camera over another based on the colors, which have nothing to do with the content of RAW files, only their translation.

I want the histogram of the RAW RGB data to apply ETTR. Why don't the camera manufacturers provide that function?

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I want the histogram of the RAW RGB data to apply ETTR. Why don't the camera manufacturers provide that function?

To reiterate, RAW files do not have RGB data. That's added after the cake is baked.

 

Existing histograms provide the information you need. RAW files have no more headroom than the current 8-bit histogram shows. They are somewhat more robust because not all three channels necessarily overload at once and you have 14-16 bit depth. Nearly complete detail can be reconstructed from 2 channels, and even one channel is better than nothing.

 

ETTR is overrated, and unnecessary with modern cameras. It is more important to NOT overexpose than to maximize the exposure level in order to improve shadow detail. With low-noise sensors and dynamic range of 13-15 stops, there is more than enough shadow detail to go around.

 

A "Faithful" style is less useful than "None". It adds color and contrast that is more appealing to the eye, while an un-profiled RAW file tends to be on the flat side.

Edited by Ed_Ingold
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To reiterate, RAW files do not have RGB data. That's added after the cake is baked.

RAW files do have RGB data and I want to look at it in-camera; every photo-site has either a red, green or blue filter and an output value; I like to see all red, green and blue values plotted in histograms to better control exposure and apply ETTR.

Existing histograms provide the information you need. RAW files have no more headroom than the current 8-bit histogram shows.

Existing jpeg histograms do not provide the RAW RGB information I'm looking for.

RAW files have different headroom than jpeg histograms show; for my particular Nikon camera there is more headroom than the jpeg histogram shows under most shooting conditions, but this is not consistent; when I shoot with an IR filter, all bets are off.

ETTR is overrated, and unnecessary with modern cameras.

We can agree to disagree on this. ETTR does more than reduce noise in the shadows; it also reduces the likelihood of posterization.

Edited by frans_waterlander
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We can agree to disagree on this. ETTR does more than reduce noise in the shadows; it also reduces the likelihood of posterization.

Posterization will occur only if you adjust the histogram by reducing its span. ETTR has nothing to do with posterization. Make that the second item you need to Google and (attempt to) understand.

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RAW files do have RGB data and I want to look at it in-camera; every photo-site has either a red, green or blue filter and an output value; I like to see all red, green and blue values plotted in histograms to better control exposure and apply ETTR.

It’s an interesting question and concept. Could you post a photo of yours that would have been better if you’d had this capability and explain what you think the photo is lacking and how a RAW histogram would have been of benefit? I think that might help the group understand the import of your question.

"You talkin' to me?"

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Posterization will occur only if you adjust the histogram by reducing its span. ETTR has nothing to do with posterization. Make that the second item you need to Google and (attempt to) understand.

Really? With ETTR you capture the maximum number of steps in the brightness range, resulting in the smallest difference between steps, minimizing the chance of visible posterization, especially important when you do post-capture editing. If you want me to, I can give you an example with some numbers thrown in to illustrate this. You also might want to read MIchael Reichmans's article: Expose Right - Luminous Landscape

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Good-bye, Franz. Argue into a mirror.

 

You know nothing and refuse to believe credible sources. Your portfolio is completely empty, which makes it impossible to see what you claim to be missing, nor to tailor responses to your needs. We are at the point of simply repeating facts which should have been sufficient the first time around.

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You know nothing and refuse to believe credible sources.

Really?

You claim there is no RGB data in RAW files, but there is - albeit in a different format from what you are used to - and when I explain that and how it directly relates to RAW files you just ignore it.

You claim that jpeg histograms provide the information I need and ignore my feedback that I really want to see the RAW data to properly expose and use ETTR.

You claim that ETTR has nothing to do with posterization and ignore my explanation why it does.

Far be it from me to accuse you or anybody else on this forum of knowing nothing, but I would appreciate an effort to constructively engage in a conversation and respond to what I'm saying and thinking outside of the box rather than rehashing what everybody claims to be the case ("there is no RGB data in a RAW file" being a nice example of that).

No, those "facts" you refer to are not cast in concrete and certainly are not sufficient in the context of what I was asking. You don't want to engage? That's too bad and I really mean that.

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Coming to this discussion a little late, I have a slightly different but related question. I use a Nikon DSLR and shoot a mixture of JPEG and raw. I usually use the Neutral picture control and photograph many landscapes. If I look at the RGB histogram and associated blinking highlights I can sometimes see that the blue channel is blown out, sometimes even making he sky look greenish. I can be pretty confident that the raw data will be OK and I can deal with this problem in post. However there is a possibility, though unlikely, that one or more of the photosites will be saturated due to excessive exposure and some indication of this would be useful. Some form of raw histogram might help with this.

 

Is that what you really need/want Frans? BTW I guess that if you were to always expose so that you just avoided saturating the photosites you would be giving an exposure far longer that you really needed with associated risk of camera shake, loss of DOF etc. etc. It's really only with high contrast subjects that photosite saturation is a risk

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Dunno; I'd be content with a histogram of the not RGB evaluated RAW. I suppose such doesn't exist because manufacturers cut engineering corners, to offer B&W cameras at all?

I have no clue about the processing power not built into an average camera. You'd have to be the hacker team of Magic Lantern (or its equivalent at camera maker side), to tell how long it would take to spit out the data Frans is asking for, with given (& known) hardware. - I suppose some marketing folks decided "that would frustrate our customers" and had the feature skipped for that reason.

Any "Why is there no?" is a request for infotainment. "How can I get the picture I want with the stuff at hand" is the problem to solve.- For landscapes I'd probably use bracketing, in a studio I'd tether, if that is an option and if it isn't I'd save up for gear permitting at least that. And in between there is hope to gather experience, to become more likely, to get things right.

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I would never be able to take a photo if I knew much about the inner workings of a camera/computer. Some things like being able to view a raw histogram are better not knowing in my opinion! Being a luddite makes me sleep better at night.
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A "Faithful" style is less useful than "None". It adds color and contrast that is more appealing to the eye, while an un-profiled RAW file tends to be on the flat side.

 

I can only speak to Canon cameras. You can only get the histogram for a JPEG conversion using a picture style, and Canon cameras don't offer "none" The closest you can get is "faithful." see Canon : Picture Style

 

With ETTR you capture the maximum number of steps in the brightness range, resulting in the smallest difference between steps, minimizing the chance of visible posterization, especially important when you do post-capture editing. If you want me to, I can give you an example with some numbers thrown in to illustrate this. You also might want to read MIchael Reichmans's article: Expose Right - Luminous Landscape

 

Interesting. Reichmann indeed wrote that. But if you look at the histograms he shows, neither has any clipping, so they both represent the same number of steps, just at different levels of luminanance. I don't see why this should have any effect on posterization.

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RAW pixels contain only luminosity data. Color is assigned later, based on coordinates of the pixel. If you view them in color, it means they have been processed. You could map these levels into an histogram, even color the chart to taste, but would it be of value?

 

Although histograms are traditionally 8-bit, they accurately represent the luminosity level, only with less resolution. A 90% level in the 16-bit file is still 90% in the 8 bit version, hence just as useful for evaluating the exposure.

 

The camera display is probably not JPEG nor a low-resolution proxy, because you do not see artifacts when you zoom into the image. In a Sony camera, the displayed image reflects the Style setting, which is imposed after the fact, but Profile settings, which are embedded in the image, are disabled. Profile settings include Log gamma and HLG, which are widely used in video, except for RAW video

 

Bits per channel has relatively little effect on exposure or dynamic range. To be photographically useful, image data is interpreted logarithmically rather than linearly.

 

The real breakthrough may be instituting 32 bit floating point data in image files. Depending on the way it is implemented, 32F can virtually eliminate overexposure, and reduce quantization noise at the lowest levels. It is becoming the new standard for audio recording, and imaging can't be far behind. I can record a drum line followed by Saint-Saens without ever touching the level controls. Peak levels appear to be clipped, but clean up when you reduce the gain. Clipping is an artifact of the interpretation, not the underlying data.

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