Discrepancy between camera & LightRoom histograms

First off... the in-camera histogram is based on the jpeg preview of the image (it's affected by whatever picture styles you have set). LR does not read this info from the EXIF, so it can't render the same image, you'd have to use IDC to get the same rendering as the one produced by the camera.

Second... I found LR's default processing settings to be... inaccurate, to put it mildly. It applies some overexposure 'under the hood', to begin with. I had modified the settings to something like:
- exposure: - 0.66 EV
- blacks: +3
- brightness: +15
- contrast: 0
and then had them saved as defaults (Develop menu - Set default settings - Update to current settings)

These values might not be exactly what you're looking for, but you can always play around with the sliders until you reach something you like, and then save your own preset.


One other thing: I was using these settings as a starting point for further processing, I reckon it would be rather difficult to find a combination that would work perfectly for all the images one takes.

Edited by cezarL - 18 May 2010 at 03:41

What you are seeing is an issue with how Adobe camera raw interprets Sony .arw files. Basically, it automatically puts the exposure up ~2/3 of a stop for A700 raw files. All you need to do is drop the exposure 2/3 of a stop to correct the issue.
You can automate the process by using the LightRoom default camera presets. That way you can make the auto import drop the exposure by -2/3 and all should be right with the world.

Here is a tutorial on how to set up serial number specific camera defaults in LightRoom. Hopefully you find this of assistance.

Basically all of the colour settings influence the histogram in some way, from contrast and saturation to white balance.
In order to get an as accurate as possible histogram in-camera, you'd probably have to resort to using uniWB (here's an explanation, there were also some discussions here on Dyxum, in the past).

I tried it too, but I got... mixed results. I decided that, for my own needs, uniWB was a bit of an overkill, I could live without it.