Archived posting to the Leica Users Group, 2000/10/25
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]"Ken Lai" <ken@compose.com.hk> wrote: > Assuming a 28 mm lens at an aperture of 2, the closest eye is at the > edge of the frame (worse case) and is at a distance of 0.7 meter from > film plane when you rotate the camera so the eye is in the center of > the frame when you focus, > > Now if you rotate the camera back to the original position so the > subject's eye is now at the edge of the frame, the actual distance to > the eye from the film plane is now 0.888 meter which means a > 0.888-0.7=0.188 meter focus discrepancy. Here's an experiment to try. Take a piece of string. Have a subject hold it tightly. Hold it in your hand, so the string is taut. Now, keeping your fingers where you hold the string in the same location, swivel your wrist. As long as you are not moving your fingers but merely rotating your wrist, the distance won't change by 7 inches. __________________________________________________ Do You Yahoo!? Yahoo! Messenger - Talk while you surf! It's FREE. http://im.yahoo.com/