DOF calculations

[Wes]

I'm figuring that Don Barnes or someone else of his ilk will know the answer to this one.....

How do you calculate DOF? Let's say that I'm 10' away from my subject shooting at 100mm at f/4. What kind of DOF can I expect? 6"? 1'? I'm really more interested in how I could do these calculations myself in order to choose the more appropriate aperture for my desired results.

Thanks!

[12stones]

This has a calculator and tells you a little about calculating it:

http://www.dofmaster.com/dofjs.html

[mom2aidan]

thats a neat little calculator there

[Joe_Lorenzini]

I think Jeff Kohn made one for smartphones... Maybe do a search on it. I always meant to install that...

_/oe

[Hanky]

There is an add in POP Photo for just such a calculator wheel (actually two wheels). I will post info if I ever get to go home from work and if SBC shipped new modem promised for today.

[jeffkohn]

Originally Posted by Joe_Lorenzini

I think Jeff Kohn made one for smartphones... Maybe do a search on it. I always meant to install that...

_/oe

http://home.comcast.net/~jeffrey.koh.../DepthCalc.htm



I guess with enough experience you could get a feel how much DOF certain focal lengths and distances give you, but to calculate it in your head to any degree of accuracy is not something most people will be able to do.

[venchka]

You could use old lenses with the DOF scale right there on the lens.

Rule of Thumbs:
Longer lenses: Less DOF
Closer focusing distance: Less DOF
Larger (bigger opening) aperture: Less DOF
All of the opposites are true.

DOF is not equally divided front to back. Very roughly: 1/3 in front and 2/3 behind the subject.

Just a hunch: 100/1:4.0 lens at 10 feet = Not very much DOF That guess is based on using my 85/2.0 lens which has almost NO DOF until you get to f=5.6 or f=8.0.

[Hanky]

Ok here is webby for calc wheel:

Disclaimer, poster has no knowledge of this wheel/wheels or manufactuer but is relaying info from magazine ad.(Shutterbug,May 2008, Vol 37 no. 7 issue 452, pg. 79)
This post has been edited because poster was not paying attention to spelling of link and furthewr more poster regrets any inconvienence this error may have caused.
revised addy is as follows
www.expoimaging.net
Final edit. removing initial addy in hopes of making 2nd addy usable.

[Hanky]

OK the spelling is good on the above addy but it does not work for me so I grabbed this one and with that I will also excuse myself from this thread because being a doofus is not as easy as I make it look.
http://www.expoimaging.net/

[Canon bek]

I need to check into this.

[barP]

i have the expoimaging dof calculator, and it wasn't quite what i imagined. i thought it would calculate much more precisely than it does and would be a useful field gadget. then i downloaded the dof master app for my ifone and solved that problem.

wp.

[110240]

google hyperfocal distance