Arlen C. Elkins , Mar 12, 2009; 07:58 p.m.
The Canon 50mm F:2.4 Macro is an excellent flat field, low distortion lens for this exact use. The Lights should be set up at 45 degree angle (90 degree total) to illuminate the image. Be sure your camera is on a tripod or copy stand and perpendicular to the copy,
Do NOT use the zoom lens, it will not have the flatness of field or resolution of the 50mm macro, and has considerable barrel or pincushion distortion depending on the focal length used.