DOF Re: [Rollei] Rolleikin REVISITED

[Robert Monaghan <rmonagha >]

http://www.smu.edu/~rmonagha/brondof.html depth of field calculator says 
for 6x6 format; 

80mm lens at 3 meters f/11 has a depth of field circa 1.98 meters from 
2.3m to 4.3

85mm lens at 3 meters f/11 has DOF of 1.72 meters from 2.37m to 4.1m

* Robert Monaghan POB752182 Dallas Tx 75275-2182 rmonagha    *
* Bronica 6x6 medium format: http://www.smu.edu/~rmonagha/bronica.html site *
* Medium Format Cameras: http://www.smu.edu/~rmonagha/mf/index.html megasite*

On Tue, 10 Nov 1998, G. Lehrer wrote:

> Steve wrote:
> > 
> > Mamiya645   wrote:
> > 
> > > In a message dated 98-11-09 21:23:15 EST,  todd_belcher  (todd)
> > > writes:
> > >
> > > >  The comparison of an 80 mm to 85 mm focal length for a 35 mm camea is
> > > >  rather moot as the difference is only 6%. I am certain that most
> > > >  photographers wouldn't quibble too much over that. If you wish to be a
> > > >  stickler about the 80 mm thing then OK. But the point is not the so much
> > > >  the focal length, but the quality. I have the Contax 80/1.4 Planar, the
> > > >  Contax 85/2.8 Sonnar and the Rollei 80/2.8 Planar. The Contax lenses are
> > > >  spectacular lenses and in my opinion equal to the task of competing with
> > > >  the Rollei Planar.
> > > ============================
> > >     Are you absolutely sure that your Contax Planar is an 80/1.4 and not an
> > > 85/1.4?
> > >     6% in focal length doesn't seem like much but at 3 meters and f/11 the
> > > depth of field of the 80 is almost 3 times greater than the 85.
> > >
> > 
> > Interesting optical fact there..3 times the DOF with 6% decrease in FL?
> > 
> > ---
> > Steve's Photography and Z car stuff
> > http://www.mindspring.com/~skoontz
> 
> Steve
> 
> I don't think I believe this.
> 
> Jerry
> 

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End of Rollei Users list digest V2 #19
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