So things here are almost back to the norm. We now have power and we will have cable/internet tonight, I hope I hope. So if I don't get back to you right away you know the reason.
The answer to my question, is a 2 parter found in a book called, "The Complete Guide To Night & Low-Light Photography" by Lee Frost from Amphoto Books. The process is call backtracking but it was more like forwardtracking for what I wanted to do.
The exposure is being doubled each time you halve the film speed. So, if your camera meter gives an exposure reading of 15sec at f/4 on ISO3200, at ISO100 the correct exposure will be 8min at f/4 (15sec at ISO3200, 30sec at ISO1600, 60sec at ISO800, 120sec at ISO400, 240sec at ISO200 and 480sec at ISO100).
Now this part works for me like this: D70s (Tyra) exposure setting of 30sec at f/22 on ISO200, at ISO50 Coolpix 8700 (Holley) the correct exposure will be 120sec at f/22 (30sec at ISO200, 60sec at ISO100 and 120sec at ISO50).
Captin' I'm givn her all I got and she will not do f/22.
Getting to the aperture you want to use by doubling the exposure each time you move to the next f/stop. Example: You get a reading of 20sec at f/4 but want to take a pix at f/16. At f/16 the correct exposure would be 5min 20sec (20sec at f/4, 40sec at f/5.6, 80sec at f/8, 160sec at f/11, 320sec at f/16).
My Coolpix (Holley) will not do the f/22 I want to use but will do a f/8 and a ISO50 that the D70s (Tyra) can't do. Using the answer from above or before, "ISO50 120sec at f/22", this is how this works for me: The correct exposre will be 15sec at f/8 on ISO50 (120sec at f/22, 60sec at f/16, 30sec at f/11 and 15sec at f/8).
Or I could have just read the post from ~souk1501
or used the link the ~cappaholic
posted. Still I had fun learning this and going old school with new tools.
Now you know what I know and thats one to grow on YO JOE --- Que GI Joe music. I think I just dated myself with that joke...
Thank everyone for helping with this one.
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