Measuring brightness objectively? (1 Viewer)

Wouldn't it be pretty easy to measure absolute brightness of a bino or scope by putting it in a studio with controlled lighting and filling the entire field with some grey background while putting some sort of light meter behind the eye peice in black box so its shielded from all light except what comes out. I guess someone here has probably already done that.

Average Joe here so best to purge anything I actually suggest. There have been various topics on it. Here are two which I thought were useful (to me).

Back in 2007 I got a "bright" idea to compare visually using a "which is better" approach a la the kind of test you'd get at an optometrist. Read about it and all its detractors here

Henry Link had a great method in a topic which was actually about color bias, but I found it quite interesting for brightness, though he would be the better judge of how good that method is for judging relative brightness. Read about it here. Since this stuff at times fascinates me, I even attempted to convert the RGB numbers to relative brightness levels. Conversion to EV would be very cool for photo guys like me. Works great if you have a digital camera that you can operate in manual mode.

BTW, depending on age, the actual impact of relative brightness may make very little diff except in extremes of dawn, dusk or shade.

HTH,
Matt

The thing about using a light meter is that your results are absolute and not relative per test so assuming your lights/meter are consistent, you can compare results from one day to results from another.

Oh, I was gonna say a spotmeter might work but otherwise I like the photo method personally.