P3D Re: Graphic's "Depth Master"

[Project3D@xxxxxxx]

In a message dated 15/03/99 19:58:04 GMT, you write:

<< I think the system is called "Depth Master".  Someone said that they
 have not seen the difference in focus between the two pictures.
 Neither have I, but you need a *wide* aperture and a subject that
 has both infinity and an object at 6-7 feet. (The pictures I have
 seen were on a sunny day and without strong foreground).>>

In actual fact, the system was something of a getaround for lenses of
unmatched focal length. Typically, one lens would be slightly shorter than the
other, so they were focussed at slightly different distances to achieve common
image size. The difference in focus was only apparent under very wide aperture
siruations.

A bigger problem with the camera is the locating device for the waterhouse
stops. Typically these will vignette at f11 and smaller, but it is detectable
at f8. Now, if the stop is not centred in the lens, one will vignette at the
top and the other at the bottom... It pays to wiggle the control to centre the
stops! 
 
 <<I am still puzzled by this system and would like to hear from a
 supporter.  People usually wear glasses because they do not like to
 see one sharp and one fuzzy image.  Why would they accept this in
 a stereo camera?  (Glasses for the Graphic?  That's an idea!)>>

In fact, where it is apparent, the brain tends to take the sparb bits for the
image and the fuzzy for the 3-D, so it's not too obtrusive!
 
<< I remember in Atlanta ISU (I think), a Stereoscopic Society (UK) 
 member presented a slide show with pictures taken with a Nimslo
 modified for full frame.  He mentioned that the lenses were adjusted
 according to the same idea, to make it "focus free".  He sounded
 as if this was a great system and said something like, "don't ask me 
 about the details for this wonderful conversion... it is complicated
 and I had it done by an expert."  Of course, you could not see the
 difference in focus in projection.>>

That would be Derek Merfield, His Nimslo does not give full frame - just 25mm
square chips with a 50mm lens spacing. I know, because I did the conversion.
And it does NOT have differencial focussing, but Derek likes to think it does,
so I leave him happy!

In practice, I have frequently seen images from this camera that are so sharp
that it is virtually impossible to tell that it was from the Nimslo rather
than Derek's Custom Realist!

One of my better conversions...

Bob Aldridge


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