We've covered light meters on this site a few times, but with a more advanced meter like the Sekonic 758Cine, you can actually set custom profiles for individual cameras and color profiles within those cameras. For example, if you have one project shooting with a log profile and another shooting with a standard profile, it's likely you'll have more dynamic range with the log profile, and thus you can light accordingly. Ryan E. Walters shares a tremendous amount of information on his site, and we've covered one of his light meter tutorials here before. Below, Ryan gives a tutorial detailing the proper way to set up a camera profile for the Sekonic 758Cine light meter.
Ryan E. Walters - Camera Profiling with the Sekonic 758Cine:
If you haven't seen it before, his video tutorial on using a light meter is fantastic:
The X-Rite ColorChecker is also a good way to properly calibrate camera picture profiles to your liking (and it's something I'll probably use in the future for camera testing). It's also helpful for color correction, as it can be brought in with the slate and used in post to judge color values for different scenes. The actual chart that he was using in the video, the Sekonic Exposure Profile Target II, while expensive, is ideal for the software that was used in the tutorial, and has patches that decrease in brightness exactly 1/6 of a stop. The original Exposure Profile Target that was mentioned should also get the job done.
Ryan has uploaded a ton of profiles on his website, from high-end digital cinema cameras like the RED Epic and Arri Alexa, to lower end camera like the Canon 5D Mark II and Panasonic GH2. If you're unsure about anything that's been detailed in the video, his website has a plethora of information, so it's unlikely you won't be able to find the answer you're looking for.
Using a light meter can be extremely helpful while lighting a scene, so that you can properly gauge where your camera is losing detail. Even though they aren't an absolutely necessity now that we can accurately see what are cameras are seeing, they take the guessing out of lighting a scene. I've used a version of the Sekonic meter in the past for video and photography (I particularly like the spot function), and while it might seem like an expensive investment, these light meters, if cared for properly, should last a very long time.
DISCLOSURE: X-Rite is a No Film School advertiser.