Archived posting to the Leica Users Group, 2004/03/02
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]> This is just a mind trick. Don't think of it as magnification, think of it as cropping. A lens is a lens, and it behaves the same whether it is imaging onto film or a digital sensor. Its depth of field is whatever it is. > > But if you are imaging onto a digital sensor, that sensor is smaller than film, which gives you a mandatory crop of your image: the outer parts simply aren't there. > > Given that your image has been cropped for you by the camera, you now must magnify it in order to produce one that is the same size that you would have gotten if you had been using film. It is this enlargement, and not some magic trick inside the camera, that modifies the image. And it works in EXACTLY the same way that the same lens would work on film if you did that amount of enlargement to the film. > Everything you said is true, but what you did not say is that when you magnify an image you reduce the aparent depth of field, and when you are shooting on a small sensor there will be more of a need to magnify the negative to produce the same size print. The magnification factor used to convert focal lengths (eg 1.5) can also used to convert the f stop. So a 35mm lens F2 lens on a small sensor digital will produce the same image on a 4 by 6 print or a computer terminal as a 52.5mm F3.0 lens. The net effect is that if you really like out of focus backgrounds they are not as easy to obtain with the small sensor digitals. - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html