When it comes to RAW, there isn't actually any profile intrinsically involved. You have to manually select how you want the RAW processor to treat your image, including Lightroom. When you first import, the "correct" image you are seeing is actually the JPEG preview that is included with the .CR2 file. When you actually select an image to edit, Lightroom will apply its own tone curve (picture style) and other defaults.
Lightroom DOES allow you to change the default settings applied to photos from a camera model, or even a camera with a given serial number. If you want the most neutral settings possible to start with, I recommend doing the following:
- Load an image taken with your 5D Mark II
- Preferably one you have not processed yet
- Enter the Develop module
- Under Tone Curve, select Point Curve: Linear
- This nullifies any kind of contrast curve that is usually applied by default
- Under Camera Calibration, select Profile: Camera Neutral
- This applies the most neutral tone curve that closely matches Canon's built-in neutral picture style
- Under the Develop menu, select Set default settings...
- A dialog should appear, showing the camera model (i.e. "Canon 5D Mark II")
- Select Update to Current Settings to apply the current develop settings to all images imported from 5D II cameras.
If you wish to have different presets for different copies of the same camera, you can configure Lightroom to use the camera's serial number as well. Do this under Preferences -> Presets with the "Make defaults specific to camera serial number" option. You can also make defaults specific to a given camera ISO setting if you wish to get that low level. That can be useful for applying default NR settings to imported images of varying ISO, however you have to be careful about what settings you change when using the
Set default settings tool...just about everything in the Develop module will apply.
While I have not done this myself, from what I understand about default settings, is that you can configure them at multiple levels. You could set default settings for any photo imported from a Canon 5D II, then set default settings for any photo imported from a Canon 5D II with a specific serial number, and further set default settings for any photo imported from a Canon 5D II with a specific ISO setting, or both an ISO setting and a specific serial number. Once defaults are set, it would just be a matter of changing the preferences to make defaults specific to serial and/or ISO before importing. I find the way Adobe implemented this feature to be rather ad-hoc and confusing. I think it would have been much more intuitive to bring this feature to the forefront with a visible button or other tool in the UI to make accessing it easy, as well as allowing you to enable/disable serial # and ISO based settings within the import screen. As it stands now, you have to remember to dive into the Preferences dialog first, tick off the necessary options under Presets, THEN import.