P3D Re: DOF Table on Realist lens cover varies among samples!

["Greg Wageman" <gjw@xxxxxxxxxx>]

From: Michael Kersenbrock <michaelk@xxxxxxxxxxxxxxxxxx>


>fstop    set-to     DOF
>
>f/8        15'      7-1/2' to INF
>f/11       11'      5-1/2' to INF
>f/16       8'       4'     to INF
>
>>
>> (The DOF table numbers I state above come from S/N A35629.)
>
>Mine is S/N A61931 and doesn't have DOF on the focus wheel nor
>the double-exposure lockout (my f/2.8 one has both of these).
>
>Seems newer.  Maybe only the lid is older?  Or maybe it's newer
>and they "improved" DOF for competitive marketting reasons?


Perhaps they changed the size of the Circle of Confusion.  This is a key factor
in DOF scales, and you're comparing apples to oranges unless you know this
parameter.

The CoF indicates how sharp their definition of "in-focus" really is.  I suspect
you're correct that marketeers may have insisted they relax this parameter,
based on what the competition was doing.

     -Greg W. (gjw@xxxxxxxxxx)



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