Archived posting to the Leica Users Group, 2001/02/06
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Photographing a 3 dimensional object like human faces will change what is acceptable DOF from what it would be if you were copying a 2 dimensional object like a blueprint. (or a newspaper test target taped to the wall) If you get the person's eye within 6 to 8mm of the exact plane of focus it'll make a cool looking portrait. If you photograph the blueprint and have exactly the same focus error of say 6mm it will look like a blurry mess. If you were not exactly square to the blueprint you might even have some in some out on both sides of the plane of focus. There is a LOT of the face that is not within the computed acceptable distance range but if the right parts ARE you're OK - our eyes and brains will accept that. That's why your print of a human can look good and the same lens and same error when applied to a flat object or small product photography will look BAD! The acceptable DOF can indeed be calculated but in the end its the subject matter and the viewing of the picture that counts. Henry Ambrose >I trust the man with the 13x19. I always choose reality over the internet. >What would you estimate the critical depth of field to be at .7m and f1.4? > >John Collier > >> From: "Austin Franklin" <austin@darkroom.com> >> >>> >>> http://www.silverlight.co.uk/resources/dof_calc.html >>> >>>> From: "Austin Franklin" <austin@darkroom.com> >>>> >>>>> Wide open and focused close, the depth of field of the 75/1.4 >>>>> is between 6mm >>>>> to 8mm (just over a quarter inch). >>>> >>>> What are you basing this number on? >> >> I don't believe it's accurate. I routinely shoot at 1.4 with both a 75 and >> an 85, and I find my critical DOF to be much much larger than 6mm to 8mm. I >> also print typically 13x19...so DOF is quite noticeable. >> >> >