| Year | 1921 |
| Date | 25-Aug |
| Volume | 45 |
| Issue | 1,061 |
| Page | 154 |
| Category | Workshop Topics |
| Part | |
| Title | Some Points on Scale Photography |
| Author | |
| Notes | General note, projecting an image of an object, effect of stopping a lens down, relative variation of conjugate distances, depth of focus, pinhole camera, effect of aperture on exposure, how to obtain conjugate distances in using a lens of known focus |