Standards like KG mentions are a fine idea in some ways.
But, I disagree about standards for aperture and exposure times. I've mentioned this a number of times before, and most especially in my thread
A new flashlight beam metrology, but the camera and the human eye are most definitely NOT the same.
You'd think that fixing everything scientifically and repeatably would be the only way to go, but the problem is that it doesn't work. You end up with a few way over-exposed shots, and a lot of shots that are basically just a bright round circle surrounded by darkness. The dynamic range of the camera isn't nearly as great as the dynamic range of the eye. And more than that, there are other differences.
The end result, is that a lot of beamshot comparisons just don't tell you very much.
I think that we need to abandon the idea of a scientific, standardized process. I propose that we go ahead and screw with whatever variables we need to
IN ORDER TO ARRIVE AT A SET OF BEAMSHOTS WITH THE GREATEST FIDELITY TO THE WAY THE LIGHTS REALLY ARE.
Yes. I'm saying "cheat in order to be more faithful to the truth."
I discovered this because my digital camera simply won't let me control things the way a camera SHOULD. It's more of a point and shoot deal. However, it has a special mode called "Night Mode" with a long-shutter open time, and special algorhthyms to better capture what a night scene looks like to the human eye. The first time I tried it, I would very doubtful about how it would work out, but to my great surprise it was a lot better than the set of shots where I locked the ISO and exposure. And I mean a
LOT better. I was like, well, I know that these are much closer to the truth, but I can't claim that they were done at the same exposure. Then I was like, SO WHAT! I have extensive experience with these beams, and I know these are pretty good beamshot comparisons. That's better than something more "objective" but with a lot less fidelity to reality.
Then, I decided that things got even better when I separated the camera from the flashlight, moving the camera a lot closer to the object being illuminated, allowing a more even light to fall across the cameras field of view. That's essentially my new beamshot metrology. That and the notion that we should cheat in order to tell the truth. If I needed to, I would mess around with brightness and whatever via a photoshop type program in order to make things better tell the truth. I don't give a damn about scientific standards because they simply don't work, and I won't be a slave to them.
However, standard ranges to white walls and trees and so on I think is a good idea.