ETA: I haven't read any of the books on simplified Zone System but...
Do you mean that you have a "reflective" light meter? How close to Zone 5 is the palm of your hand? If you know how your skin tone differs from Zone 5 then, yes, you can meter off your hand and compensate for that difference. If you do have an incident meter then the only way to meter how much light is falling on the shadows is to walk into the shadow area as far as you can and aim the dome at the camera to take your reading. Then you'll need to decide if important details in those shadows are particularly dark or light and need more or less exposure. If you can't get to that area then, yes, you could meter with your shadow on the dome but it won't be as accurate because the surrounding spill light is different. Also, many times shadow areas are deeply recessed which means they are probably far darker than any shadow you cast in the same light. Oh... and pray that the light doesn't change during this process. Are you able to buy a spot meter?
Last edited by Old-N-Feeble; 04-08-2012 at 02:39 PM. Click to view previous post history.