Hi,

I enjoy long exposure photography very much. I do some of it in digital, which is quiet easy. But at changing light and considering Schwarzschild effect, it get's more complicated.

I use a Sekonic L-758 for metering. Most of the time incident, but sometims spot metering. I am to slow on spot metering, have to practice it more
Then I use two Android apps to do the compensation. ND Filter Calc to get the compensated time and then Exposure Assistant, which calculates the Schwarschild effect for several film brands and ISOs.

From the technical point it's straigt forward and clear, although I would wish to have an app, which could somehow take over the metering and do both compensations. But that's another story...

Where I struggle now is how to compensate for the changing light during dusk and dawn. How do you handle this? Also passing clouds are not that easy to handle. Do you have any rules of thumb how to compensate?