Archived posting to the Leica Users Group, 2005/06/29
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]http://www.imx.nl/photosite/comments/t001.html explanation of the effect on perspective and dof best,simon jessurun ----- Original Message ----- From: "Howard L Ritter, Jr" <hlritter@mindspring.com> To: "Leica Users Group" <lug@leica-users.org> Sent: Wednesday, June 29, 2005 9:38 PM Subject: Re: [Leica] new Puts article >I still believe that what I posted before is correct: If you take two >photos > at the same f/ ratio, from the same distance, with different focal length > lenses and different size sensors (or not, it doesn't matter), and then > print both pictures scaled and cropped to show the same area and the same > subject size, the pictures will look identical including the DOF. > > The photo taken with the shorter FL lens will have a smaller CoC on the > sensor, but will have to be enlarged proportionally more to make the > subject > the same size, offsetting the smaller CoC. The DoF with a smaller sensor > and > shorter FL lens will be deeper only if the print is enlarged to the same > _degree_ (e.g., 15 x the sensor size) not the same image scale (e.g., > subject's head 2" high), because the viewer will be looking at detail that > appears smaller and not see unsharp focus as well. > > Same distance + same f/ ratio + same subject size on print = same DoF. > > --howard > > ----- Original Message ----- > From: "Adam Bridge" <abridge@gmail.com> > To: "Leica Users Group" <lug@leica-users.org> > Sent: Tuesday, June 28, 2005 4:16 PM > Subject: Re: [Leica] new Puts article > > >>I don't understand this, Henning. >> >> It seems to me that the depth of field is solely a fuction of the >> geometry of the lens/film system. That the print and enlargement has >> nothing to do with it. >> >> If I took an R8 with a 50 shot wide open at f1.4 I'd get some depth of >> field. I replace the back with the DMR. Same shot. Same depth of field >> but cropped. >> >> So then I open the images on photoshop and look at them. How does the >> depth of field change? >> >> So I'm confused but I could certainly be enlightened! :) >> >> Adam >> > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information