Re: Aperature calulation.

[P3D Brian Levy <dlevy@xxxxxxxxxx>]

Actually, each is a multiple of 1.41 therefore starting at 1.0 you have
1.41, etc. You see it rounded of in charts and on the lenses since it
doesn't make a whole lot of difference. About the only time one needs to
think about it is when you really need accuracy with the aperature size in
the order of about 1/10th EI accuracy though even at 1/3rd it may be
critical with slide film or b&w with little latitude sich as Tech Pan.

At 03:48 PM 1/10/97 -0600, you wrote:


>Date: Fri, 10 Jan 1997 14:54:28 -0500 (EST)
>From: P3D  <PTWW@xxxxxxx>
>To: photo-3d@xxxxxxxxxxxxxxx
>Subject: Re: f/6.3 or f/6.8? & Three R's
>Message-ID: <970110145424_1358935604@xxxxxxxxxxxxxxxxxxxx>
>
>>Actually, f/6.3 is _exactly_ in-between f/5.6 and f/8 exposure-wise 
>>for the same reason that f/8 is between f/5.6 and f/11 (instead of 
>>f/8.3).  We are dealing with sqare roots here.
>


>The doubling part is easy but square roots...geez, haven't done
>them in about 20 years!  But what do you take the square root
>*of* to find an inbetween f-stop value?
>



Brian Levy, J.D.
Agincourt Ont.
dlevy@xxxxxxxxxx


------------------------------