ZoneCalc

A simple old-school circular slide rule to help you apply the Zone System to your photographs. No struggling with calculations involving EV, ISO or shutter speed. Granted, the ZoneCalc won't solve all your exposure problems. However, it is a handy tool while you're learning how to apply the zone system. No more trying to remember what to subtract from what and what to add whenever.  And once you're more experienced, it serves as a quick and easy check to verify that your planned exposure is probably going to workout as you hope. Instruction Summary: Take a reading in the darkest feature where you want to see detail. Rotate the f/stop disk to place the reading under the desired Zone marker, normally Zone III. Take a reading in the brightest area where you want to capture texture. Without moving the f/stop disk, align the f/Highlight marker with the highlight reading. Read the processing adjustment needed under the Development factor indicator: N+0: You're good to go! Expose using the