How important is it to properly adjust the settings on your camera when taking pictures if you can change white balance, exposure, etc. in ACR?
It is critical to get exposure right in the camera. If the dynamic range of the scene is less than that of the camera, you have some exposure latitude, but it is best to expose to the right so as to get a better signal to noise ratio. Some degree of overexposure can be corrected in ACR, but blown channels (the green usually blows first due to white balance) result in loss of data and the colors may not be accurate. The white balance set on the camera does not affect the raw data, but is merely stored as metadata. If there is no neutral reference in the scene (a WhiBal or similar card is better than a white T-shirt), the an accurate white balance may be hard to obtain. In this case, it is better to use a WB preset by taking a reading from a white balance card.
ACR ignores camera settings other than WB, so the contrast, saturation and tone curve set on the camera are of no significance.
When you shoot raw, for maximum image quality you want to get these right:
- Exposure (ACR has its limits...don't clip highlights, don't underexpose)
- ISO speed (to avoid unnecessary noise)
- Focus point (for maximum sharpness)
- Aperture (for desired depth of field)
- Shutter speed (to prevent motion blur)
Just about everything else is negotiable in Camera Raw.