Archived posting to the Leica Users Group, 2003/12/27
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi, One interesting thing occurred to me is the "reversed" thinking of DoF. Instead of a set of parameters like a given lens, aperture and distance (and then to figure out the DoF), it seems to me that DoF and the "size" of image commands the aperture to use for a given lens. Probably portraits are the most popular and sensitive case for DoF usage. In this case, for regular adult portraits of head and shoulder shots, we typically want to have a DoF about 4" for facial contour before taking a picture. Therefore, you may roughly use 50 focal lens at aperture of 2 or 85 at aperture of 4 (to get comparable image size at whatever distance needed). I don't see a such "DoF" calculator (it should be called "aperture calculator" for given DoF - modern camera can have this built-in (little different from canon's DoF priority)). To me this is more useful. In most cases, people know ahead what DoF they want and the image size (which determines the distance and is part of composition). What they don't know is what aperture to use. btw, the marking on lens is hard to use for such large aperture. [To make it topic-related, in order to use Noct's max aperture with DoF of 4", you may have to be roughly 6' away.] Happy holidays! Lee __________________________________ Do you Yahoo!? New Yahoo! Photos - easier uploading and sharing. http://photos.yahoo.com/ - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html