[Bobr99]

no the histogram shows the final captured image, if you used exposure compensation this will be factored into the image

I don't know about that? I'm no expert but this is what was happening to me. I am only shooting in RAW format and this should only work with RAW format not if you shoot in JPG format.

I would go out shoot some shots that looked good on both the histogram and the image displayed on my camera lcd.

I would load those images up on my computer and they would all be a lot darker with not much detail.

Did some research that said the histogram you see on your camera is a/the JPG image. Taking in all the camera settings (contrast, brightness, sharpness...). But the RAW image is just that a RAW image that is not effected by the camera settings. Only the JPG images are affected by those. It's like trying to use the in camera filters in RAW format. The camera will not let you.

I checked it out with my images. Those images before I changed my camera had a histogram on the camera that was not the same as what I had on my computer. Once I changed my camera settings and moved all of them to the far left, not just zeroed them out. My histograms on the camera match the histograms I am getting on my computer almost exactly.

This is on a K100D. The newer cameras might be different. Try it out on your camera and see what you get. But once I changed my camera settings I have not had a problem with exposure when I download them onto my computer. Before that every shot I took was different.

Bob

[Bobr99]

Here's another post about it from dlacouture. I tried to find the original site that I found it at but couldn't.

All the RAW aficionados around here must have run into the same problem: how to know when your RAW RGB channels really clip, as the histogram displayed is based on the preview JPG and thus doesn't really show what is in the RAW file.
Anyone tried to properly expose a Tungsten scene? You always end up with at least 1Ev underexposure, due to the seemingly clipping Red channel on your camera: once you get into your PP software, it magically transforms into a one-stop highlight headroom, so you're forced to push the exposure and noise really starts to creep in.

I personally find that getting satisfactory JPG previews right out of the camera is pretty useless for the RAW shooter (as every photo I make goes through ACR), and I'd rather like to have an accurate histogram.

https://www.pentaxforums.com/forums/pentax-dslr-discussion/68043-finally-came...histogram.html

Bob

[Marc Sabatella]

The color channels sometimes look better than the overall histogram, but now I'm getting confused with this whole .jpg being the histogram rather than the RAW. Does this mean if I use exposure compensation the histogram won't reflect that?

Exposure compensation affects the actual exposure - that is, the shutter speed or aperture or ISO is altered. That means it affects both RAW and JPEG. So yes, it is reflected in the histogram.

The distinction between JPEG and RAW is relevant mostly if you've messed with image processing settings, like increasing contrast, which will affect the JPEG but not the RAW data, and it will be reflected in the histogram. Also, the histogram will reflect the image with the selected WB applied, but in RAW there *is* not WB applied yet, so a change in WB selected during conversion will affect the conversion. And also, there may be highlights that were clipped in the conversion from RAW to JPEG and hence show as clipped on the histogram, but there might well be room to recover them in PP from the original RAW file.

All of which just adds to what I said before - thehistogram is very useful as a rough guide to what you've capture, but don't get caught up too much in the specifics, because it doens't tell the whole story.

[Lowell Goudge]

I don't know about that? I'm no expert but this is what was happening to me. I am only shooting in RAW format and this should only work with RAW format not if you shoot in JPG format.

I would go out shoot some shots that looked good on both the histogram and the image displayed on my camera lcd.

I would load those images up on my computer and they would all be a lot darker with not much detail.

Did some research that said the histogram you see on your camera is a/the JPG image. Taking in all the camera settings (contrast, brightness, sharpness...). But the RAW image is just that a RAW image that is not effected by the camera settings. Only the JPG images are affected by those. It's like trying to use the in camera filters in RAW format. The camera will not let you.

I checked it out with my images. Those images before I changed my camera had a histogram on the camera that was not the same as what I had on my computer. Once I changed my camera settings and moved all of them to the far left, not just zeroed them out. My histograms on the camera match the histograms I am getting on my computer almost exactly.

This is on a K100D. The newer cameras might be different. Try it out on your camera and see what you get. But once I changed my camera settings I have not had a problem with exposure when I download them onto my computer. Before that every shot I took was different.

Bob

while I agree that all the jpeg settings are applied to the raw image for review, exposure compensation has nothing to do with JPEG settings.

Exposure compensation works directly with the metering before you take a shot., It impacts shutter speed and aperture (and if in use auto iso). This concept has been in use since film days and nothing has changed.

[K-9]

So from what Bob and Marc are saying, it sounds like the RAW file you see in camera is with JPG like settings applied (WB, exposure comp., etc.) but when you upload it into a RAW converting program, it resets back to even settings? Is that why your histogram changes, Bob? Then it is true to some degree that the in camera histogram is what a JPG would be if you shot JPG, and the uploaded RAW file later is without in camera settings applied? It's starting to become even harder to make out now as I try to write and interpret this.

[Lowell Goudge]

So from what Bob and Marc are saying, it sounds like the RAW file you see in camera is with JPG like settings applied (WB, exposure comp., etc.) but when you upload it into a RAW converting program, it resets back to even settings? Is that why your histogram changes, Bob? Then it is true to some degree that the in camera histogram is what a JPG would be if you shot JPG, and the uploaded RAW file later is without in camera settings applied? It's starting to become even harder to make out now as I try to write and interpret this.

The settings used by your raw converter depend upon the converter and the options you select.

Some use the Jpeg settings, some apply nothing, others make their own corrections, and you can turn these on or off.

I use PSP X2 and it seems to use the jpeg settings or with an option, apply it's own "smart photo fix" settings after scanning the image

[Bobr99]

So from what Bob and Marc are saying, it sounds like the RAW file you see in camera is with JPG like settings applied (WB, exposure comp., etc.) but when you upload it into a RAW converting program, it resets back to even settings? Is that why your histogram changes, Bob? Then it is true to some degree that the in camera histogram is what a JPG would be if you shot JPG, and the uploaded RAW file later is without in camera settings applied? It's starting to become even harder to make out now as I try to write and interpret this.

Not really. What you see on your camera lcd is a JPG image not the RAW image. You never see the RAW histogram on camera. You only see the RAW histogram once you load it onto your computer.

The camera settings that I'm talking about are not shutter speed, f stop and iso. Only the settings in the menu option. Which I do believe are brightness, contrast and sharpness. Those settings should not have anything to do with your shutter speed, f stop or iso setting. Those options are only applied after you take the photo by the in camera processor.

It's easy to test. Just change the brightness, contrast and sharpness in the menu option and take a few photos. Take 4 or 5 photos both with the camera settings all the way to the right and all the way to the left. While in RAW format. But keep the other camera settings the same (shutter speed, f stop and iso). Download the images on your computer. See what each look like on the lcd and computer. Compair the histograms from your computer and also the histogram on your camera.

Hope this helps.

Bob

[Eruditass]

As a rule of thumb it's better to keep the histogram over to the left, but not touching it, as digital sensors will have more detail in the darks than they will have with burnt out highlights.

ChrisJ

Actually, you have more detail to the right because there are more bits there (logarithmic) and less noise (more SNR). Then pull the exposure back while PP. ETTR works as with film - except you must be very careful not to ETTR too much because there is no compression in the highlights as with film so you can clip highlights much easier. But if you don't clip, the shadows and highlights will have more detail and bits representing them.

[Class A]

So from what Bob and Marc are saying, it sounds like the RAW file you see in camera is with JPG like settings applied (WB, exposure comp., etc.) but when you upload it into a RAW converting program, it resets back to even settings?

There is no "resetting" taking place.

RAW data encodes light intensity linearly and if you would simply render these linear levels on to the camera LCD, you'd see a very dull image (ignoring the fact that one needs to "demosaic" RAW data in order to get a viewable image). In order to get something that resembles the actual scene one has to apply a tone curve (including gamma correction), apply white balance, etc. Since it is reasonable to assume that you'll have to do these steps in a RAW -> JPEG conversion outside the camera as well, the in-camera histogram is based on the viewable image rendering of the RAW data.

The RAW data is untouched at all times but sometimes (in-camera display, in-camera histogram) it has to be "cooked" so that one can view it. Depending on your RAW converter, the result of the out-of camera RAW development will be per default based on in-camera settings (for white balance, contrast, saturation, sharpness) or not. All these settings will influence the histogram of the developed image.

The histogram of the RAW data as such is irrelevant as you cannot look at RAW data directly. It only matters because it determines what you can cook from it. If the RAW data lacks certain information (e.g., because there is underexposure and you have no details for the shadows plus little dynamic range for the whole scene) then you cannot recover this during RAW development. So a RAW histogram is only useful in the sense that it tells you how well you used the dynamic range of the sensor but the histogram of the final image will look differently (depending on the RAW development settings).

[Marc Sabatella]

So from what Bob and Marc are saying, it sounds like the RAW file you see in camera is with JPG like settings applied (WB, exposure comp., etc.) but when you upload it into a RAW converting program, it resets back to even settings?

Again, exposure compensation is *not* a JPEG setting. As the name implies, it affects the actual exposure - it changes either shutter speed, aperture, or ISO. And as such, it's not something that a RAW converter could change if it wanted to.

But as for the JPEG settings - contrast, WB, etc - then these do not affect the RAW data, so in that sense, it is indeed as if they are "reset". Although *some* WB has to be applied, and most programs will look at what you had set in camera and use that as a starting place.

[LeoTaylor]

Most of the people on this thread know a lot more about histograms than I. But, in case there are some who don't and would like actual examples taken with a K100D, here is a little demonstration I wrote for a friend who never used a histogram.

Histogram Examples

P.S. For those who are curious, I got the photo of the histograms by using an istD and Pentax Macro aimed at the back of the K100D. Crude but effective.

Forget about the histogram. Your much better off using the warning for the highlits otherwise known as the blinkies. The histogram can't tell you which highlights are blown. If it's a shot of the sun well of course that's blown. But if it's a white shirt you don't want that blown. The blinkies are a lot better since it indicates WHAT is blown.

[LeoTaylor]

I'm a big fan of the "blinkies" as graphicgr8s called it. As my little tutorial pointed out to my friend it is hard to tell when something is too white. Having it flash has saved me many times.

I only with the istD had that feature.