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Re: [OM] "Depth of Field being too deep on the 4/3"

Subject: Re: [OM] "Depth of Field being too deep on the 4/3"
From: "Paul Farrar" <farrar@xxxxxxxxxxxx>
Date: Mon, 3 Mar 2003 10:04:40 -0600 (CST)
It's a problem with all formats, not just digital. It may, or may not
be an actual problem for a particular case. Large format photographers
have a problem with too shallow a depth of field in some cases, but they
get a break on diffraction limitation, so they can stop down more.

As you increase the size of a sensor (digital or film), you must 
proportionately increase the focal length of the lens. The allowable
circle of confusion increases linearly also. But hyperfocal distance
increases with the square of focal length. DOF has a more complicated
relationship, but for distances well short of the hyperfocal distance,
DOF will decrease as the inverse of hyperfocal distance.

Now that I've confused the issue, the short answer is that, if you
have a digital sensor half the size of a 35mm frame, you'll get double the
DOF close up at the same f#. It's an optical thing, not a digital thing.

Paul

> 
> Can someone explain all this to me please?
> Are we saying that with a small sensor size the DOF is inherently deeper?
> Then it should follow that with a large sensor (like 5" x 4") the DOF is
> almost non-existent?
> Thanks
> jez
> 
> 
> 
> 
> 
> "Bill Pearce" <bspearce@xxxxxxxxxxxxx>@Zuiko.sls.bc.ca on 03-03-2003
> 04:15:12 PM
> 
> Please respond to olympus@xxxxxxxxxxxxxxx
> 
> Sent by:    owner-olympus@xxxxxxxxxxxxxxx
> 
> 
> To:    <olympus@xxxxxxxxxxxxxxx>
> cc:
> Subject:    [OM] "Depth of Field being too deep on the 4/3"
> George,
> Isn't this an ongoing problem with all less than fulll 35 digital cameras?
> Even if there is a way to manually control dof, doubtful of course, it is
> usually impossible to get it really shallow?
> Bill Pearce
> 
> 
> 
> 
> 
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