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Wollensak f/stop

  • From: P3D John Bercovitz <bercov@xxxxxxxxxx>
  • Subject: Wollensak f/stop
  • Date: Wed, 24 Apr 1996 19:24:35 -0700
> The added speed? If f/2.7 is truly the speed of the lens, it would be  
> about 2/3 of a stop faster (f/2.5 being a full stop from f/3.5?).
 
Just a guess but maybe what BobH meant by a whole stop was making it to 
the next stop in the conventional series:
 
 1.0	 1.2	 1.4	 1.7	 2.0	 2.4	 2.8	 3.4	 4.0
 4.0	 4.8	 5.7	 6.7	 8.0	 9.5	11.3	13.5	16.0
16.0	19.0	22.6	26.9	32.0	38.1	45.3	53.8	64.0
 
Often enough, 2.7 stands in for 2.8 on a lens.
 
John B


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