Re: [MF 3D] MF viewer lighting

[Greg Erker <erker@xxxxxxxxxxxxxx>]

>The [pair of] reflectors for the twin 35mm viewer are acrylic mirror pieces
>forming truncated pyramids with square bases 1.5 in. on a side (the diffuser
>side), square tops 7/8 in. on a side (where the 4 LEDs are mounted in the
>corners), and a 1 in. height between the base and top.  This will evenly
>illuminate full frame 35mm slides in landscape or portrait mode.

  Sounds great.

>The CCFL backlight I made for the Saturn viewer measures 11.8EV @ ISO 100
>through
>the eyepiece.  The inverter draws 285mA @ 5.9V (~1.7W) when powered from a
>wall
>transformer.  Keep in mind that the 35mm twin viewer is only illuminating
>a total
>of 4.5 square inches of diffuser, while the MF viewer illuminates about 14
>square
>inches of diffuser.

  If you are measuring brightness through the
eyepiece of a viewer then the area doesn't really
matter. Assuming an ortho-ish viewer then the
light meter sees a lit area of roughtly the same
angle. So the same amount of light (say 4 LEDs)
shining through a 20x20mm mount should measure the
same as if you move it back and illuminate a 50x50mm
mount. The total light reaching your eye is the
same either way.

  Or am I wrong somehow?

Greg