[Leica] A tripod, an M8, and two candles - do some science

[abridge at gmail.com (Adam Bridge)]

If infra red is really a prime illuminate in the image then the focus
will be shifted because of the substantially longer wavelengths of the
IR. So you'd expect the focus to be "off" - if it weren't I'd be
thinking IR wasn't an issue.

I'd like to see some rigorous science done here - creating a
thoughtful series of controlled experiments to explore what is being
observed and determine the meaning.

Adam


On 1/7/07, Jim Nichols <jhnichols@bellsouth.net> wrote:
> Brian,
>
> I don't wish to get into the definition of depth  of field or allowable
> circles of confusion.  However, if you go to the full size image in the
> second photo, you will notice that the highlights on the rim of the neck of
> the oil candle are not nearly as sharp as the highlights on the frame in 
> the
> background.  This is what led me to state that the sharpest focus is behind
> the candle flame.
>
> Jim Nichols
> Tullahoma, TN USA
> ----- Original Message -----
> From: "Brian Reid" <reid@mejac.palo-alto.ca.us>
> To: "Leica Users Group" <lug@leica-users.org>
> Sent: Sunday, January 07, 2007 11:49 AM
> Subject: Re: [Leica] A tripod, an M8, and two candles
>
>
> >
> >> I am assuming that you were careful not to change the focus between the
> >> two shots.
> >
> > Correct.
> >
> >> I notice in the second shot that the frame in the background seems to be
> >> the plane in focus.  The IR effects are interesting, but I do not think
> >> that you have eliminated the focus question.
> >
> > According to the manual that came with the Noctilux, the depth of field 
> > at
> > f/5.6 at that distance (1.5 meters) is about 22cm. I believe I have
> > eliminated the focus question.
> >
> > (http://www.leica-camera.us/assets/file/download.php?filename=file_153.pdf,
> > page 6)
> >
> >
> >
> > _______________________________________________
> > Leica Users Group.
> > See http://leica-users.org/mailman/listinfo/lug for more information
> >
>
>
>
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