Archived posting to the Leica Users Group, 1999/07/07
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I believe DOF is determined by image size. That is, if you set a Noctilux at f/1.4 and frame a scene, then set a 75 Summilux at f/1.4 and frame the same scene exactly like the Noctilux (The Noctilux is closer to the scene than the Summilux in order to have the exact same image on film) the DOF of both lenses will be exactly the same. If you stand at exactly the same place and take the photograph, at f/1.4, with both lenses, the Summilux will record less of the scene than the Noctilux. 75mm vs. 50mm. The Summilux will have less DOF, in this circumstance, than the Noctilux. The f/1.0 DOF statistics belong only to the Noctilux. The Summilux at f/1.4, focused at it's closest position, might possibly have less DOF than a Noctilux at f/1.0 focused at its closest position. Perhaps exactly the same. This is a good project for someone. I believe the 75/1.4 close focus/image size is the best of the M lenses. I have a photo of a tulip, printed 16x20 on Ciba, that I took with my 75/1.4, at f/1.4, and focused at its closest position. The DOF is literally the front surface of the tulip. Barely a few millimeters. Jim At 07:40 PM 7/7/99 -0400, you wrote: > >If I remember correctly, DOF, to first order, depends on the absolute >aperture. The noctilux has an aperture of ca. 51mm, whilst the 75/1.4's >is about 54 mm. I'd expect the noctilux to have greater DOF wide open. > >As always, I'm open to correction. > >Regards, > >Akhil > > >> Mark Rabiner writes: >> >> > I'm wondering what the difference would be a say 4 feet away DOF wise >> > both lenses wide open? >> > My hunch is the Noct would give you about 1 inch front to back and the >> > 75 would give you 2. >> >> At 4 feet the 50mm f1 gives you 1.44 inches, the 75mm f1.4 gives you 0.72 >> inches. >> >> So you were close, but the wrong way round. >> >> David Morton >> dmorton@journalist.co.uk >