Hi there,
I have been viewing the pictures taken by Chuck Clark from Tikaboo peak.
I note that the focal length of his telescope was 1250mm and then he used 2
2x adaptors to quadruple the power from it. This was a total of 5000mm focal
length lens.
To calculate the zoom on these photos, do you divide the focal length by
35mm (being the film size)? Or is there some other way of accurately doing
this.?
I have access to a telescope which with the same setup of teleconverters
will give an 8000mm focal length.  I am trying to work out if this is worth
carting all the way up the peak.

Regards
-John