Which histogram to trust?

I'm finding that the in-camera (or in-DPP) histogram is way different from the one I get when I open the image in ACR.

Here's what I get in DPP and the camera, showing no overexposed highlights (and plenty of room to spare). Camera Picture Style is custom, based on Landscape with Sharpness set to zero and Contrast set to one. In DPP, all I do is apply lens correction and save as a TIFF.

IMAGE LINK: http://www.flickr.com …scubadude1960/8​581917676/

IMAGE LINK: http://www.flickr.com …scubadude1960/8​580816289/

In-camera and post-production histograms are different. The in-camera histogram tells you about DATA, the other gives you TONE information. Shoot the in-camera histogram to have the most amount of data possible (shoot to the right), then adjust to taste in post.

Staszek wrote in post #15745288
In-camera and post-production histograms are different. The in-camera histogram tells you about DATA, the other gives you TONE information. Shoot the in-camera histogram to have the most amount of data possible (shoot to the right), then adjust to taste in post.

I understand that, but if the in-camera histogram won't tell me how far to the right to shoot, what good is it?

Understand that the in camera histogram is based on a JPG that is generated in camera using you camera style settings. ACR is not going to be an exact replication of that because it will use a camera profile that is not the same as what is generated in camera.

This is what I do to ensure I'm maximizing my exposure VIA using the in camera histogram:
Camera style neutral, -4 contrast others zero.
This will give you about as unbiased a histogram as you're going to get.
When the highlight alert blinkies flash on anything white, I drop 1/3 stop. I only shoot in full ISOs.

What happens when you upload to ACR really depends on where your presets are set. The first thing I do when I upload to ACR (or LR) is to set a custom profile, then WB.

Windpig gives good advice about what in-camera settings to use so that the in-camera histogram most closely matches the actual raw exposure. I go even farther and set all in-camera picture style sliders to their max negative value. But also consider that the in-camera white balance will drive changes in the histogram much more than the picture style settings. If your in-camera white balance is way off, it can cause an very inaccurate histogram.

But I think your question is more about why the DPP histogram does not match the histogram in ACR or Photoshop when DPP actually processes the raw file and transfers a tif to Photoshop/ACR. I don't use DPP much, but my limited experience is that the histogram in DPP sucks. Especially the small histogram that is shown with the thumbnail in a file list. It's a grayscale histogram that averages the RGB channels. I don't know what kind of grayscale conversion DPP uses to do that average, but there could be clipping in one or more of the RGB channels that does not show in the grayscale histogram due to the averaging.

I think that's the case in your sample. The blue channel is clipped and ACR shows you that. DPP does not.

If you are always going to be working with RAW files, make sure your jpg settings are all set to standard or natural. That way, your screen jpg will be unmodified in any way and will give you the truest representation of what your actual RAW photo is going to look like.

The in-camera histogram can help you to shoot "to the right" -- shoot so that the histogram is not clipping (with Contrast being pulled back).

Then, in ACR, the RGB data has been "rendered", which may show some clipping, but then all you need to do is pull the relevant sliders, pull back Highlights in this example, and the Raw data will "line up".

DPP will just "reflect" what you saw in the camera, whereas ACR does its own rendering.

Also, make sure you set the in-camera histogram to "brightness" instead of "rgb", and enable Highlight alert.

I trust my eyes.

Will pushing the contrast to -4 in the camera's picture styles affect the final RAW?

Only if you use DPP to import your RAW files; however, it will affect the jpeg preview that you see on the LCD screen.

Alveric wrote in post #15745690
Will pushing the contrast to -4 in the camera's picture styles affect the final RAW?

When you pull the contrast back in the Picture Style settings it will affect the "Luminance" histogram, in that it will display a "toned down" version of what the jpeg would be, more accurate to what the Raw file would show...

tonylong wrote in post #15745706
When you pull the contrast back in the Picture Style settings it will affect the "Luminance" histogram, in that it will display a "toned down" version of what the jpeg would be, more accurate to what the Raw file would show...

But the picture that ends up in LR will not be flatter, will it?

I have heard that picture styles and some other camera features (lens vignetting & dust, for example) only work if you use DPP, which I don't. Is this correct?

I shoot with the Neutral picture style set in camera: all dials set to 0.

tonylong wrote in post #15745597
The in-camera histogram can help you to shoot "to the right" -- shoot so that the histogram is not clipping (with Contrast being pulled back).

Then, in ACR, the RGB data has been "rendered", which may show some clipping, but then all you need to do is pull the relevant sliders, pull back Highlights in this example, and the Raw data will "line up".

DPP will just "reflect" what you saw in the camera, whereas ACR does its own rendering.

When I pull the exposure back down in ACR, the blown out areas are flat, with no detail.

Thanx, everybody, for the suggestions. I'll change a few settings and see how it works.

Snydremark wrote in post #15745645
Also, make sure you set the in-camera histogram to "brightness" instead of "rgb", and enable Highlight alert.

incorrect white ballance can cause a brightness histogram to be off. I prefer to use the RGB histogram and have a look at all the channels. I find the green channel to yeild the most accurate histogram.