Archived posting to the Leica Users Group, 1997/10/16

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Subject: Re: Min shutter speed for hand-held steadiness
From: Eric Welch <ewelch@ponyexpress.net>
Date: Thu, 16 Oct 1997 09:40:30 -0500

At 12:43 PM 10/16/97 +0800, you wrote:
>> ...
>> =A0=A0=A0=A0=A0The usual accepted figures are:
>> =A0=A050mm lens ------ 1/25 =A0to 1/50
>> =A0=A090mm lens ------ 1/50 =A0to 1/100
>> =A0135mm " =A0=A0=A0=A0" =A0=A0=A0=A01/250 or faster
>> =A0=A0=A0but this would be based on a particular circle of confusion of=
=20
>> =A01/100" (I think).
>> ...
>
>I agree with you on these figures.
>I am not sure, but I think the circle of confusion just
>decides the depth of field, which should have no direct
>relation to the min. accepted shutter speed for steadiness.
>However, it is very possible that the circle-of-confusion
>blur (out-of-focus blur) can be analyzed mathematically/optically
>to get the relation to the blur caused by camera/lens=20
>unsteadiness.

Okay, you are mistaken. The 1/30 circle of confusion might not be the best
way to put it, but the figure of 1/30 is how they define sharpness. And if
you want to be able to distinguish objects that are 1/100 across, then you
need the camera to be steadier than if you only want objects 1/30 or larger
to be sharp. Does that make sense?

=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D
Eric Welch
St. Joseph, MO


God is REAL, unless explicitly declared INTEGER.