viewer brightness

[Greg Erker <erker@xxxxxxxxxxxxxx>]

  I've been playing around with my Cabin light
panel to see how various batteries affect
the brightness. Here are the results I got
and it also includes some old measurements
on my Dr. T halogenized Red Button viewer
and my MF viewer with old lighting method.

  I used my Polaris meter in reflected mode
to measure EV's (for 100 ASA). Each full EV
is one stop brighter/dimmer.


  Viewer     Conditions               EV reading (100ASA)
--------------------------------------------------------
1 Dr.T RB    Nicads  new/mid charge    12.5/12.0
2 MF viewer  plexi diffuser 3pm sun    17.0
3 MF vwr plexi lit by light box        13.7
4 MF vwr plexi lit by frosted halogens 12.1/11.6
--------------------------------------------------------
5 MF w/Cabin, no diffuser 4 AAA nicad  11.5
6 MF w/Cabin, no dfsr, ext 4 C nicad   11.2
7 MF a/a ext 4 C alks (2 new, 2 mid)   12.3
8 MF a/a ext 5 C nicads                12.5

Note 1: Lighting isn't perfectly even. So these
numbers are the highest ones I got. Fresh nicads
put out 1.25V per cell for a while so you get
a higher number for a short while. The rest of
the discharge curve is pretty flat so the mid
charge numbers apply.

Note 2: My MF viewer with 3mm white plexiglas
diffuser lit by 3pm summer sun. Very even lighting :)

Note 3: As 2 but places on top of my home made
light box which contains a 17W compact fluorescent
bulb and diffused with same type of plexi.

Note 4: Using my viewer's attachable light box.
The two numbers are for fresh charged nicads and
mid charge. Lighting isn't perfectly even but is
the same for each eye since the bulbs are centered
behind the two film chips. Uses two 0.8A 2.5V frosted
Dr. T halogens.

Notes on 5-8: My MF stereo viewer without diffuser
lit by the Cabin Light panel. #5 is with the mid-life
alkaline AAA's that came with it. Would be brighter
with brand new ones.

Note 6: I changed the connector on the external four
C-cell nicad pack I used to use with my halogen lighting.
It has about 3 or 4 feet of 18 Ga wire so there is a
small resistive drop.

Note 7: I didn't have 4 new C cell alkalines so I used
two new and two mid life ones.

Note 8: Using 5 mid-charge C cell nicads. I measured
6.2V at the pack so probably 6.1 or 6.0 volts at the
Light Panel.

Last note: the 5000K bluer light from the Light Panel
seems brighter than an equivalent EV of halogen light.

---

My viewer is a bit brighter than before (plus more even
lighting and bluer). How does it compare to what
other's are using. Say Alan's fluoresent lit SaturnScope?

Greg