Re: Re-calibrating Kodak Focus

[P3D <klein@xxxxxxxxxxxxxxxxx>]

On  8 Sep 97 at 17:38, P3D Robert Linnstaedt wrote:

> Dear Colleagues,
> 
> I have now mustered the  courage to work on my Kodak Stereo Camera, to
> eliminate its focusing problems.  I seek your guidance.  The camera is in
> top working order, except that the focus is way off from the marks on the
> lens barrel.  In use, I have stopped down (up?) to smaller apertures and
> lengthened exposure, even to making 30" time exposures.
> 
> Can anyone suggest proper procedure for this fix?  I have already
> fabricated a "ground glass" from a strip of 35mm film.  My plan is to
> mount the camera on a tripod, the back open and the "ground glass" in the
> usual film channel.
>  With aperture at f/3.5, a cable release will hold the shutter (B) open
>  while focusing.

This is actually a fairly easy procedure and should take not longer than 5 
minutes if you're experienced (about 15 minutes for a "regular" user). The 
description so far was O.K.

> The room will be dark except for a lit candle placed at a
> carefully measured distance.  I'll wear my reading glasses so I can see
> more detail in the image.  When the flame is correctly focused on the
> film, I will be ready to do the next step....

I never use a candle at a close distance. I just set it up by the window 
and focus on an antenna which is several hundred yards away.

> But what is the next step?  I do not know the correct way to go about
> changing the lenses from the old calibration to the new.  There are two
> small screws on either side of each lens; do I remove these?  Should the
> camera be placed in a particular position so nothing falls out?  Is there
> a particular distance I should use for this re-calibration?

This is what you want to do:

a) remove the four small screws holding the retaining-rings (brown rings 
with "Kodak Anaston ...") with a suitable small Phillips screwdriver (x).

b) take a small screwdriver (-) or a needle to remove the retaining-rings. 
If they don't come out, just move the aluminium ring round the lenses a 
bit (that's the part you grip with your fingers to adjust focus). You 
should now be able to turn this aluminium-ring (actually the two are 
linked) without turning the actual lenses.

c) once both retaining-rings are removed, open the back, set to f/3.5 and 
B, cock the shutter, use a locking cable release to keep the shutter open 
and put onto a tripod. Put the ground-glass (very fine) on one side and 
closely look with a strong magnifier (I'm using a 20x) at some very fine 
detail at infinity. If necessary, take a small screwdriver (or a peice of 
wire from a paper-clip), go into one of the two screw-holes where the 
retaining-rings were and rotate slightly left or right until you have the 
best focus. Repeat the same procedure with other lens.

d) carefully rotate the outer aluminium-ring to the "INF" position and 
hold. Put one aluminium-ring back on one lens, holding it tightly, and put 
the retaining-rings back on and srew-in the two phillips screws. Repeat 
procedure with other lens. In any case, make sure NOT to rotate the actual 
lenses.

e) with the retaining-rings and everything else back in place, 
double-check the focus, turn the lenses to a close distance and turn the 
camera itself also to an object at that distance. Check the focus again 
for that close distance. It should be O.K., then go back to the infinity 
adjustment and double-check.

> If someone could please help me, it night save much anxiety and/or
> damage.

If you need further assistance, contact me off-line. Good luck!
Alexander Klein
3D-Magazin, Editor (http://www.stereoscopy.com/3d-magazin)
Webmaster: http://www.stereoscopy.com


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