Need clarification of Nikon D50 Spot Metering
Trying to measure luminance of luminous paint on watches or clocks using spot metering. Manual says spot is a 3.5mm circle (or 2.5% of frame) but I can't find where this "3.5mm" is located. Surely not in the actual scene!? Is it possible 3.5mm referred to the image sensor (not the 420 px metering sensor)?