Use an incident light meter with the flat diffuser. If the light is bright enough to get reliable reading then you're ok. Set the ISO at 25 times the paper speed in your case about ISO 150. Get the reading in EV. If you get EV 0 then use 1 sec exposure. For every EV step higher than 0 halve the exposure time. It should give you exposure of zone V. Measuring this way is really like a spot meter but using an incident meter. Oh you can set the aperture on the meter at f/1.0 then the shutter speed is what you are going to use.
Originally Posted by Leave Me Here