Re: PHOTO-3D digest 1365

[P3D Gregory J. Wageman <gjw@xxxxxxxxxx>]

Neil Harrington corrected me thusly:

>I don't think that's quite right, Greg.  I've got a Revere 33 also, and the
>instruction manual gives the following table for flash synchronization:

>TYPE OF LAMP                SHUTTER SPEEDS
>------------                --------------
>Class "M"          T, B, 1/2, 1/5, 1/10, 1/25, only
>                  Marked in RED on Shutter Speed Ring
>
>Class "F"           All Shutter Speeds Except 1/200
>
>Strobe Lights             All Shutter Speeds
> (Class X)

I was working from memory which was obviously faulty, and also I glossed
over some details.  Thanks for setting me straight.

But this chart actually clinches my supposition!

The Revere, at least, must always fire the flash when the shutter is fully
open, thus the X-sync at all speeds.  Class "M" lamps have a 20 millisecond
delay (1/50th second), thus can only be used at 1/25th or slower where the
shutter will be open long enough to allow for the delay.  Class "F" flash
lamps have a 5 millisecond delay (1/200th second), so the only shutter
speed which is too fast for them is 1/200th.  Makes perfect sense.

The only question remaining is, "Does the Realist work like this too?"
Dr. T. says "Yes!", and unless I can find the elusive information my
now questionable memory says I once saw, I am going to believe him.

	-Greg


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