Re: Tolerance

[Glenn Barry <bonza1@xxxxxxxxxxxxxx>]

Hi All,

You can try this website they have a lot of info on lenses, including
MTF tests and actual focal lengths.

Glenn

Edward Meyers wrote:
> 
> On Thu, 29 Apr 1999, Robert Durn wrote:
> 
> > I have just taken some test shots with my new home made "Roboscope 2"
> > camera! It uses 120 film stock and a 24mm Nikon lens. The image measures
> > 152mm on the negative for a full 360 degree. Using the 2 x focal length x Pi
> > rule it should be 150.796mm. Is this within tolerance? The images are
> > sharp-ish but I'm not sure if the lens is mounted at the correct distance to
> > the film. Should it be 46.5mm for Infinity?. Any thoughts?
> >
> > Rob Durn.
> >
> > Also at Robert.Durn@xxxxxxxxxxxxxxxxxxx
> >
> No problem. Marked focal lengths are rarely true. Manufacturers
> like to round off the numbers and fudge on the side that's more
> desireable. This is why Erickson of Florida, USA, uses zoom
> lenses. After the camera is complete he makes tests at slight
> focal length variations to find the right one for the "disc".
> Ed

-- 
Glenn Barry Photography
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2007 Australia
Ph/Fax (612) 9211 3080
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