Focusing Distance & DOF

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fotojack

Senior Member
Not exactly a tutorial, but I thought this would graphically explain the concept.

Focus Distance.jpg
 
hark

hark

Administrator
Staff member
Super Mod
Nice graphic! I know there is slightly more DOF behind the focus point than in front of it. Is there a consistent ratio between the front and back (like 40% in front and 60% in back?) I don't think it is ever 50/50 at any aperture, is it?
 
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Steve B

Senior Member
There are a couple of apps for the iPhone and iPad that give you a lot of info in a graphical format about DOF based on aperture, focal length, distance, and camera type. The ones I use also give hyper focal distance for a given setup.
Also a good calculator for web browser use at http://www.dofmaster.com/dofjs.html
 
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Steve B

Senior Member
hark said:
Nice graphic! I know there is slightly more DOF behind the focus point than in front of it. Is there a consistent ratio between the front and back (like 40% in front and 60% in back?) I don't think it is ever 50/50 at any aperture, is it?
Click to expand...

As focus distance to subject increases the ratio approaches 1% to 99% as the focus distance approaches the hyper focal distance. Once you are focusing at or beyond the hyper focal distance the ratio becomes meaningless since you have infinite DOF behind the subject. At a very close focus point the ratio is close to 50/50.
 
zain

zain

Senior Member
I also find these tables showing hyperfocal distance in this link very useful as it covers all the known format, full frame, APS-C, APS-H, APS-C for Canon and 4/3rd. There is also formula for you to calculate the hyperfocal distance on your own. (It is easily done using MS Excel).Please check out this link - Depth-Of-Field Hyperfocal Distance Charts
 
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