I'm searching for the webpage of the autor of the next image.
It's a real foto, no photoshop, the man make insteresting experiments with electricity.
I believe i read about it here, but can´t find it.
The olympus OM-2 had a really neat feature called "off the film metering" which was a sort of active metering system. You open the shutter and it automatically closes when it reaches the correct exposure. This is great for capturing lightning/electricity or any scene with rapidly changing light and long exposures.
Most modern film cameras use off-the-film-metering for flash exposure but I don't know of any modern camera (film or digital) that has an active metering system.