Hi--

>>The plane location is done by the body - the actual framing/plane-location
>>is determined by the (moveable) frame in the body that the GG sits on top of.
>
>Right, but the resin screen is held in place in it's frame by clips that fit
>over that
>shallow lip around it's edge (know what I mean?) so while the plane location
>of the bottom edge of the screen's frame is done by the body, the
>the final location of the bottom ground surface of the screen itself
>is really dictated by how thick the
>portion of the screen that lies beyond the lip is. I was wondering if
>you know for a fact that the F3/F4 screens have the same dimensions
>in this regard so that the location of the ground surface has the
>same final position as would an original F screen?

No, the bottom surface of the screen rests on the frame in the camera
(and causes the edge marks on the screen surface when the screen has
been in and out of the camera several times). The prism has springs
that force the viewing screen frame (and the screen surface) down
onto the body frame - otherwise, the loose fitting of the "glass"
in the screen frame would make focus accuracy iffy at best.
The frame in the camera also, therefore, determines the framing
accuracy (the screen frame is slightly larger than the body frame
that the screen surface rests on).

>>> You suggsted the F4
>>>screen in particular. They are a bit more expensive that F3 screens
>>>so is their any advantage?

Yes:
>>They are a bit brighter than the "red dot" F3 screens, which are a bit
>>brighter than the "non-red-dot" F3 screens.

>How do you tell "red dot" F3 screens? The K screen in my F3 has type in
>red on the edges of the screen but there is no red dot.

Then it is the earlier, slightly darker, non-red-dot screen.

>thanks again,
>chip
>chipk@crocker.com

You're welcome.
David Ruether