Archived posting to the Leica Users Group, 1997/07/27
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On 27 Jul 97 at 16:17, Willem-Jan Markerink wrote:
> Btw light losses through mirrors:
>
> A normal SLR with secondary mirror has a reflection/transmission
> split of 66/33 (film receives 100% when the mirror is up of course),
> a pellicle mirror has a split of 33/66.
> This means that only one stop (66/33 = 2x = 1 stop) is lost to the
> prism, not 1.4 stop (100/33 = 3x = 1.4 stop).
> The mirror in the 1n RS is also much brighter than in the normal 1n
Ooops, that should read 'viewfinder screen', not 'mirror'!
> (and also more expensive), so the effect in the viewfinder is hardly
> noticeable....but I believe it is harder to focus manually....it can
> be retrofitted with other, normal screens.
- --
Bye,
Willem-Jan Markerink
The desire to understand
is sometimes far less intelligent than
the inability to understand
<w.j.markerink@a1.nl>
[note: 'a-one' & 'en-el'!]