[MF3D.FORUM:800] Re: Viewer magnification vs negative enlargement

["David Lee" <koganlee@xxxxxxxxxxxxx>]

> When we say that our 80mm FL MF viewing lenses are a 3x
> magnification, how does that compare to negative enlargement
> calculations?   Are enlargement and magnification measured
> the same way?  Is viewing a 2-1/4" chrome with 80mm FL
> lenses roughly equivalent to viewing a 6-3/4" print? (In
> terms of evaluating sharpness, for example.)  Or is it
> like viewing a 9" print (1+ method)?  Or something totally
> different?
>
> Paul Talbot
>

Depends on how far away from the print you are when viewing it. Simply
divide the size of the print (say 10") by the size of the negative (2.25")
equals 4. Multiply 4 by the focal length of the taking lens (say 3") equals
a viewing distance of 12" for that particular size print. In 2D parlance
this is called "the proper viewing distance" and in 3D it is orthostereo.
You can calculate the proper viewing distance for any print using this
method and it will be the equivalent of viewing in a viewer with a focal
length the same as the taking lens.

David Lee