I already stated you can choose ANY reference you want ( a particular COC for example) it doesnt matter, if you want to increase or decrease DOF, regardless of your reference, only image mag/f-stop can CHANGE it.
I think what your trying to do is define DOF absolutely, via a maximum COC for example. This is fine if you know and understand that concept. But changing your COC size only changes the way you MEASURE the DOF, it doesnt change the actual DOF. IF if WANT more or less DOF it does not matter how you define/reference it, only MAG/FSTOP changes will increase/decrease the DOF ***COMPARED TO YOUR REFERENCE, WHATEVER YOU CHOOSE*** All the other varibles cancel out and your left with only MAG and F-STOP to increase/decrease DOF. JC O'Connell hifis...@gate.net -----Original Message----- From: pdml-boun...@pdml.net [mailto:pdml-boun...@pdml.net] On Behalf Of Bob W Sent: Tuesday, April 07, 2009 3:41 PM To: 'Pentax-Discuss Mail List' Subject: RE: Trading resolution for depth of field > Sir, > > MY "burden of proof" is no greater than yours. > If you cant provide any reliable "proof" > that my contention is not true, then > your word is no better than mine. You haven't supplied us with anything that is falsifiable. All you've given us is unsupported assertions. > I dont need > any more "proof" to support my contention than > you need to support yours. > I've provided you with definitions of terms, a mathematical formula and a published reference. Others have pointed you to definitions and formulae which state the same thing as me, and which also have published references, including references from companies such as Kodak and Zeiss and the leading optical scientists. > This is very simple. DOF is all about magnfication > and f-stop. > > I did supply the formula, > > relative DOF = F-stop number/MAGNIFICATION. > > INCREASING F-STOP NUMBER OR DECREASING IMAGE MAGINIFICATION increases > the image relative DOF. > > Conversely, > > DECREASING THE F-STOP NUMBER OR INCREASING THE > MAGNIFICATION decreases the image relative DOF. > > If you dont believe me, do some experiments. > I have, its called about 35 years of practical > experience to back up what I have read in theory. > This isn't my theory, this is the correct theory > that I have read and found to be true over the years. I have as much experience of practical photography as you do. I can cite theory, and I can provide references. You cannot provide references, and the formulae you have provided do not include definitions of terms (such as DOF), so they're useless. Give us a respectable reference which supports your claim and these so-called formulae. Bob -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
