How done it? (play on who done it)

[Alexander.Of.Oz]

Interesting. I've read professionals talk about reciprocity failure even with digital. Somewhat academic as in practice I make an initial "best guess" exposure and then review the results on the histogram and adjust as needed for subsequent exposures.

Set your camera to 1/250 with a good exposure and no blown-out highlights, then set in 4.5 minutes for your 16 stopper! Simple, works every time*!

* works every time does not work when the light changes severely, or when the sun is setting or rising

 

[Apple fanboy]

Set your camera to 1/250 with a good exposure and no blown-out highlights, then set in 4.5 minutes for your 16 stopper! Simple, works every time*!

* works every time does not work when the light changes severely, or when the sun is setting or rising

Lol. We don't all live in the sunny country you do! Those settings are standard here without an ND filter