Hmmmm...;-)
The diopter will shorten the effective FL, maintain
the effective relative aperture, and shorten the
focus distance, if all else is held equal. In itself,
this would not have the effect of reducing DOF
except for the closer focus (offset by the wider
angle of view...). The focus in camcorders is different,
though, and is often achieved by moving the CCD instead
of the lens (which would not in itself change things),
but this arrangements often permits correct distance
focus with diopters added, unlike for still cameras with
fixed correct infinity-focus. (I use this to make one-scene
shots going from a tiny bug occupying most of the frame
to a wide garden shot...) I don't see, though, how
this can result in much of a change in DOF compared
with not using the diopter and simply shooting closer
with the widest stop set and the longest practical
zoom position used...
On Sat, 29 Mar 2003 02:41:28 +0000 (UTC), Claire
<claire@showstoppersfx.com> wrote:
>
>Provided the subject is not too far away I'd like to
suggest the use of a
>simple 1x diopter lens to achieve the shallow depth of
field required.
>
>Unlike true Macro lenses, a simple type of close up lens
like this costs very
>little. I have a set of three (x1,x2,x3) and find them
invaluable for blurring
>out backgrounds behind objects such as flowers and
insects. The 1x size still
>allows me to focus on objects several yards away while
retaining a short depth
>of field.
>Claire@showstoppersfx.com
>Wedding Collection animations
>http://www.showstoppersfx.com
>
>> If you really want to cheat the look- you need to
use various tricks -
>> dictated by the shot you want... a center focus
filter is a nice trick, also
>> there are filters that are designed with different
focus areas on top and
>> bottom- they are supposed to be used to bring
distant objects into focus
>> along with close objects- the exact opposite of
what you want, but if you
>> spin the filter around and focus your camera
properly, it will cheat the
>> look.