Re: hyperfocal

[Tom Deering <tmd@xxxxxxxxxxx>]

On 11/6/99, Eric Goldstein wrote:
>> If you go to the "3D Encyclopedia" page on Rocky Mountain Memories'
>> home page <URL:http://www.rmm3d.com/> you'll find an HTML reproduction
>> of the Sputnik manual which includes a hyperfocal table in meters.
>
>
>This table is wildly optimistic IMO... perhaps it is meant for viewing
>contact prints under very low or no magnification. Under normal 3x
>magnification, there is no way a 75 mm lens will yield DOF from 6 feet to
>infinity @ f/22 in MF... perhaps f/45 would get you close...

At one time, I thought DOF was based on how good the glass was.  I 
assumed the reason one 50mm lens had a different DOF than another 
50mm was due to some inherent property of the lenses.

Then I found out that depth of field is based on a mathematical 
formula.  One of the variables is for a measurement of precision 
called the "circle of confusion".  You can think of it as a 
measurement of "acceptable fuzziness". Some lens manufacturers 
specify a larger COC, which gives their lens a greater DOF at the 
expense of softer focus within this range.  I'm guessing why the DOF 
table listed above was so, let's say, optimistic.

I have a spreadsheet that calculates the DOF of the Sputnik (or any 
other camera.)  You can punch in the COC that you are comfortable 
with.  If anybody wants a copy, write to me off-list.

Tom Deering