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01-09-2012, 06:52 PM   #1
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Front/Back Focus vs DOF= 1/3:2/3?

I see numerous methods for testing lens/camera for front/back focus. They seem to all say that the resultant focused area should be equally distributed front and back of the focus point. But then I read that typical DOF extends 1/3:2/3 around the point of focus.
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Are these notions in conflict?

Thanks!

01-09-2012, 07:31 PM   #2
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Try it for yourself in this link

The answer though is that it is not a fixed proportion, it varies depending on a few different factors (eg the focal length, the aperture and the subject distance).
01-09-2012, 09:04 PM   #3
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Great info...thanks Twitch!
01-10-2012, 04:57 AM   #4
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The short answer is that at infinity it is split 1/3-2/3. It moves a little toward 50/50 as you focus in I think the absolute measure is based upon the ratio of subject / focal length

01-10-2012, 01:47 PM   #5
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QuoteOriginally posted by Lowell Goudge Quote
The short answer is that at infinity it is split 1/3-2/3. It moves a little toward 50/50 as you focus in I think the absolute measure is based upon the ratio of subject / focal length
lol
You do know what infinity means right?

At macro the focus distribution is 1:1 and past the hyper-focal distance the focus is 1:infinity

Depth of field
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