T3D Re: geometry of a MF macro camera

[john bercovitz <bercov@xxxxxxxxxxx>]

> ...the depth of field is the same if the linear aperture is the 
> same and the final magnification is the same.

That's like if you shoot something in 35 mm and then blow it up 
4X to make it the size of a 4x5 transparency.  That's what I mean
by magnification in this case.  So for instance if the linear
aperture is the same and the distance from the lens to the subject
is the same then all you have to do is enlarge the smaller result
to be the same size as the larger and the DOF will be the same.

Of course, angulary speaking, the exact same film in two different 
sizes of format will have different resolutions because the linear 
resolution, lines per mm, is the same in both cases but the distance 
of the lens from the film won't be the same.  This argues that a 
medium format macro camera should be better than a 35 mm format 
macro camera.

John B


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End of TECH-3D Digest 376
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