[LargeFormat] Macro depth of field
Mike Finley
largeformat@f32.net
Wed Jan 22 07:16:03 2003
but depth of field does depend on acceptable circle of confusion on the
negative, surely?
I think the other factors have a greater effect than this. I'll look up the
math and check.
-----Original Message-----
From: largeformat-admin@f32.net [mailto:largeformat-admin@f32.net]On
Behalf Of Ole Tjugen
Sent: 22 January 2003 11:24
To: largeformat@f32.net
Subject: Re: [LargeFormat] Macro depth of field
22.01.03 11:57:21, "Mike Finley" <mike@efikim.freeserve.co.uk> wrote:
<snip>
>
>There are then two things affecting depth of field (assuming same lens and
>aperture):
>I can use a larger circle of confusion on the 5x4 negative, as it won't be
>enlarged as much, increasing depth of field.
>I am shooting at a higher magnification on the 5x4 (1.5x rather than
0.75x),
>decreasing depth of field.
>
>I think, from looking at a couple of negatives, that the latter has greater
>effect, giving me overall less depth of field with 5x4 film than a
roll-film
>back, assuming the same aperture. I haven't tested this properly though.
>
>Can anyone confirm this?
>
>thanks,
>mike
>
In one word: Yes.
The reproduction ratio ON THE FILM determines DOF - that's why "cheap"
consumer digital cameras have too much DOF to be usable for
macro.
Using the same ratio at the same aperture, DOF is the same regardless of
film type and size - as well as lens focal length!
Ole
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