[Leica] The F-Stop's Here

[Buzz Hausner <Buzz@marianmanor.org>]

I was taught that f-stops were calculated by multiplying the previous
figure...starting at 1...by the square root of 2 (circa 1.4142135623731, if
I recall correctly).  This information could be wrong, I've never found it
useful information in my day to day activities as a photographer.

	Buzz Hausner

- -----Original Message-----
From: Marc James Small [mailto:msmall@roanoke.infi.net]
Sent: Monday, March 06, 2000 1:54 PM
To: leica-users@mejac.palo-alto.ca.us
Subject: Re: [Leica] 50mm f1.5 Nokton question


At 10:17 AM 3/6/2000 -0700, John Collier wrote:
>This from a long time ago, with my memory that is about a week, but I
>thought it went:

The surface of a circle is pi x radius squared.  I don't have lenses at
hand, but roughly, the putative radius of a 50mm f/1.4 lens is 17.86mm,
that of an f/1.5 lens is 16.66mm.  Squaring these, the ratio is
318.9:277.56.

Reducing this gives 1.14, or 1 1/7.

Mayhaps my math is way off?

Marc

msmall@roanoke.infi.net  FAX:  +540/343-7315
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