On Mon, 19 Aug 2002 21:53:49 GMT, Rudy Garcia wrote:
>In article ,
> "Kevin Neilson" wrote:

>> A watch is pretty flat, so I would think you would get enough depth-of-field
>> on F/32. Remember that the focal range is exponential, so to maximize DOF,
>> you focus in front of the object, because if the DOF is 3", then 1" of that
>> is in front of the focal point, and 2" is behind it. Check your DOF
>> indicator on the lens.
>>
>> You could also make a pinhole cover for the lens, but you would get a lot of
>> diffraction.

>Actually, in closeup or macro work the DOF is roughly equally divided in
>front of and behind the plane of focus.
>
>The not very accurate 1/3 in front and 2/3 behind rule doesn't apply in
>the macro domain.

I don't think it applies at normal distances, either.
It does in theory, but equal "out-of-focus" for DOF
coverage often looks worse on the far side than it does
for the near-side (particularly in landscapes), possibly
because the "scale" of the detail is smaller on the far
side of focus, requiring greater sharpness for similar
subject parts to look about equally sharp on both sides
of the actual focus plane...