When in times of need, especially when I’m shooting with film and have to guesstimate exposure, I use this:
To download and make your own exposure meter, click here. Courtesy Andy Lawn, Dave Harris and Rick Oleson.
The best way to use it? Guess the exposure first after studying the light levels, then look at the paper meter to gain further assistance. Once a guesstimate is made, you can use the DSLR or meter to further understand your choices. The more you use it, the better you will get at correctly estimating light levels.
If you want a more dependable meter to learn lighting, this here is not only cheap, it’s perfect:
Also read my article on the Zone System here.
I see a lot of people going back and forth from the LCD monitor to the dimmer knobs on the back of the light. Why not get good at imagining the light and exposure first? I’m still learning how!