On 6/4/09, Bob W, discombobulated, unleashed: >To calculate the nearest (dn) and furthest (df) points in focus use the >following formulae: > >dn = U * F^2 / [F^2 + (U * c * f)] >df = U * F^2 / [F^2 - (U * c * f)] > >where >c = circle of confusion >U = subject distance >F = focal length >f = f-number > >To calculate the circle of confusion > >c = (v * D) / (1000 * S) > >where >v = film format / image size >D = viewing distance >S = print size > >Source: The Professional Guide to Photo Data, 3rd edition, by Richard Platt. > >Very easy with a spreadsheet.
* F . u (2) - 'no*vv Pi55 o'.ff -- Cheers, Cotty ___/\__ || (O) | People, Places, Pastiche ||=====| http://www.cottysnaps.com _____________________________ -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
