Thomas Bantel wrote;
>You seem to think about DOF a little different than I do. Namely as an >invariaby fix zone, that depends on aperture and focusing distance >only............................................................... >If I wanted to guesstimate (which is not too hard BTW and I >do it most of the time anyway), I'd avoid DEP mode alltogether and use AV >or M. Thomas you should go back over the threads and you will discover that your concerns have already been addressed. To reduce the size of the CoC (which I agree should be smaller than 0.035mm, as this is really only good up to 7x5, even by Canon's own admission) you simply decrease the aperture. Decreasing by 1 stop gives 0.025mm and by 2 stops gives 0.017mm, a factor of 0.7071067 (half the square root of 2) for each stop. This is easily achieved by the method I mentioned previously which is to; 1. switch the lens to MF to maintain the focus point determined by A-DEP mode 2. switch camera mode to Av 3. select 1 or 2 stop smaller aperture then A-DEP suggested to achieve desired CoC 4. reframe and repress shutter to obtain correct EV reading for scene (shutter speed will determine if you need IS, monopod, tripod, whatever). Thats it. This sounds much more complex than it is in practice, especially after you've done it a few times, but it works. The ideal solution would be if Canon were to provide a CF to allow selection of CoC size. Bear in mind however, that if you accept that 0.035mm is good up to 7x5 prints, then 0.017 is going to be good only up to 14x10. A compromise becomes almost inevitable as close focus distance will often result in very small apertures which in turn give very slow shutter speeds unless you use high speed, higher grain film. Such is life and optical restraints. Cheers Norman * **** ******* *********************************************************** * For list instructions, including unsubscribe, see: * http://www.a1.nl/phomepag/markerink/eos_list.htm ***********************************************************
