[Mack]

This is a calculator/Stop reference I designed for myself for when I do night photography. It helps me to calculate exposure times by taking away the guess work. With this you can work out long exposures from a test exposure. I have seen simular illustrations but never for this particular purpose. True it has a wider application but I use it spacifically for long exposures because its a reminder of the 1 stop scale. It's a handy addition to my camera bag.

Hope it's a help to you too.

 

[yustr]

I like the F-stop side but I'm not so sure about the ISO side. (Multivariable algebra was never my strong suit.) In your example the difference between 2 minutes (at F5.6) = x2 x2 x2 = 16 minutes (at F16) no problems. But going from ISO 3200 to ISO 100 only adds 2 minutes???

Also, the F-stop and Shutter speed are from least light (at the top) to most light (at the bottom) but the ISO is opposite. I'd be tempted to invert that list for consistency. Unless, of course, I'm missing something - which is more than likely.

Help. What aren't I seeing?

 

[Mack]

Fixed!

Yes that example was a type-o. I only added that yesterday. The main thing is the stop gap. I have reversed the iso as it's confusing.

Thanks for the feedback.