Another Stereo 225 update

[Greg Erker <erker@xxxxxxxxxxxxxx>]

  Picked up my test rolls on Friday
and analyzed them on the weekend.

  The shimming seems to have done the
job. Image size is less than 2 thou
different over 1.5". So size difference
is now down to 0.13% (on infinity shots).
(Was 0.34% before the shimming).

  Focus at infinity is good. I took a
couple shots of Venus (the planet) at
f3.5 and f5.6. The dot size is exactly
the same on L & R indicating focus match
and the same for f3.5 and f5.6 indicating
focus is at infinity. I'm very pleased.

  My newspaper on the floor shot shows
the near focus to differ by about 3"
(at 2 metre focus distance) between L & R.
A second shot at f8 looked very good, mostly
hiding the slight focus mismatch.  I don't
forsee shooting wide open much or ever so I'm
happy with the optics and focus as they
now are.

  The above 3" difference was determined
using a 10x loupe (actually a 28mm camera
lens from a dead P&S). I mounted both
shots in 80x132 mounts and viewed them
with my viewer (40x84mm lenses) and found
the focus difference to be very hard to
see even on the f3.5 shot.

---
  Test shot hint: to test for FL match
by overlaying L & R it helps to have
"thin" images since they darken down
when overlayed. So slides should be
somewhat overexposed and negs should
be underexposed.

  I didn't to this with my second test
rolls (neg film) and it was hard to
line up the street light poles in the
dark double negative.

---

  My second light leak test showed no
improvement. Actually it looked worse
thanks to faster film and longer exposure
of the camera seams to the sun.

  Again the top coupler hole was leaking
light to the right film only. About 1/2"
high and across most of the film width.
Bad.

  After some head scratching I stuck a
red button type halogen bulb into the coupler
hole, stuck the AA battery holder in the
taking lens body cavity and closed up the
back (mostly).

  Then I could see light shining out the
top, and lots out the front seam, but none
out the back.

  Sticking the bulb in the bottom coupler
hole showed a similar situation.

  Pure luck and the shiny bearing on the
couplers make it so only the top right
fogs!

  I stuffed some black felt into the gap
between the two bodies through the coupler
holes. There was some improvement.

  But I decided to get some black leather
and cover the seam between the two bodies in
the front and top. Then I shouldn't have
any problems. Even if I ever shoot 400 speed
film.

  Overall I'm very pleased with how things
are looking.

Greg