On Wed, 15 Nov 2000, Paul Prior MD wrote:
> On Thu, 16 Nov 2000 11:52:20 +0900, "Jim Davis" <[EMAIL PROTECTED]>
> wrote:
>
> >> I had a question pop into my mind today, probably simple, but I
> >> couldn't explain it.
> >>
> >> Wide aperture lenses have shallow DOF, this I know. My 2.8L and
> >> 1.4/50 both produce a striking blur and I probably shoot the vast
> >> majority of my pics at 3.5 and below.
> >>
> >> Why, then when you are looking through the camera to focus these
> >> lenses do you see the whole field in focus? Isn't the lens operating
> >> at wide open aperture when focusing in EOS cameras? >
> >> --
> >> Paul Prior .
> >
> >Paul, if you are indeed seeing the whole depth of field in focus, you must
> >have set your custom function to show DOF. Check your functions.
> >You should certainly be viewing wide open as a default.
>
> Ah, but that is my point - wide open should show the LEAST depth of
> field, yet the viewfinder to me looks like it is at f16 all the time
> in terms of DOF.
Sorry, I think I missed it, but what camera do you have? If you have one
that has DOF-preview (either from ECF, CF and button or as in EOS
1/1N/3/1V from a dedicated button) then do the following. Change camera to
Av and set the aperture to f16 for example. Then focus to something close
(that gives even smaller DOF). Then use your DOF-preview. The image will
go dark, but the parts that have been out of focus are now "sharper".
(Above when I said to focus to something close, make sure that there is
something more distant in the view also.) You should see the difference
easily. Just try this with your 50 f/1.4 and focus to your knee or
something... and well just try it. :-)
Bye,
Hugo.
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** Hugo G�vert **
** [EMAIL PROTECTED] http://www.hut.fi/~hugo **
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** Sometimes I think the surest sign that intelligent **
** life exists elsewhere in the universe is that none **
** of it has tried to contact us. -- Calvin. **
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