Hello all.

I'm trying to wrap my brain around the zone system concepts at the moment. Before I take the plunge and try it out I want to confirm I have a basic understanding of the process used to actually meter a scene, check for contrast range and develop accordingly. So here goes....

Say I have in my scene (my backyard) a dark fence which I meter 1/500th at F/4 and I want to place this at Zone 3. According to what I know thus far, I would reduce the exposure by two stops and make it say.... 1/500th @ F/8.
Now this is the part where I think I need some clarity. Say in the scene there is also pathway in full sunlight and I want to place that on Zone 7. I take a light meter reading of the pathway and get 1/500th at F/22. I now have a difference of 3 stops between my Zone 3 and future Zone 7. To get to the 4 stop difference I require I now need to develop at my known normal development time plus 20% to get the extra stop ?

What if my lens has max aperture of f/22 and I needed to add 2 stops to shutter speed and ended up with 1/2000th @ f22. I would now have 5 stop difference from my Zone 3 reading? I would then devel
op my film at known normal development time minus 20% ?

Hopefully above makes some sense. Pointers appreciated! (I have a zone system induced headache now )