One answer is to make a substitute reading off the palm of your hand, providing that your hand is illuminated by the same light as your subject, then use a lens opening 1 stop larger than the meter indicates. For example, if the reading off your hand is f/16, open up one stop to f/11 to get the correct exposure. The exposure increase is necessary because the meter overreacts to the brightness of your palm which is about twice as bright as an average subject. When you take the reading, be sure that the lighting on your palm is the same as on the subject. Don't shade your palm.