Re: Exact fl of lenses... 220 VR

[Bill Glickman <bglick@xxxxxxxx>]

The fl in the roundshot is the only variable given to the user to effect the
horizontal stretching and compressing.  The more stretched or compressed an
image, even to a small degree, the less sharp it is....

Bill G

----- Original Message -----
From: "Andy Buck" <buckwiet@xxxxxxxxx>
To: <panorama-l@xxxxxxxxxxxxxxxxx>
Sent: Wednesday, June 14, 2000 12:40 PM
Subject: Re: Exact fl of lenses... 220 VR


> The only thing that comes to my mind (weak and twisted
> as it is) is that if your aspect ratio changes from ss
> to ss, then the camera is not moving the film through
> at the correct rate for the rotation speed, something
> that is the most basic requirement of a rotating
> camera. As Andy DH said, fl shouldn't have anything to
> do with it. I've never had this problem with a Hulcher
> and get very sharp images at any speed. People
> complain about Hulchers being over (German)
> engineered. It sounds like the Roundshot is even more
> so (or maybe too under?). Please excuse my cynicsm.
> Andy
> --- Bill Glickman <bglick@xxxxxxxx> wrote:
> >
> >       That was my unfortunate discovery, and it
> > makes sense.  I can nail
> > down a fl to .1mm at a given shutter speed.  Works
> > perfect every test...
> > aspect ratio is dead on.  However, when using the
> > same fl, but change the
> > shutter speed from 1/125 to 1/15, I can not
> > reproduce the same aspect ratio.
> > All other test variables remained constant.  It
> > makes sense... because
> > unless the motor speed is in sync at exactly every
> > shutter speed,  you will
> > not be using the optimum fl.  For the random checks
> > I did, none worked out.
> >

> >
> > In a previous post a gave exact examples of this.
> > But this new found knowledge puts me in a
> > quandray..... all 50 rolls of my testing were
> > practically useless, unless I always shoot at the ss
> > I tested at.  Otherwise I must test each of my 4
> > lenses at every ss to find the exact. fl setting.
> > If not, one might as well just throw an educated
> > guess in and hope for the best.  For now, I will try
> > my hardest to use the ss where my test results were
> > perfect.... if not, I'll just take my chances.  The
> > amont of testing to determine all this information
> > is time and cost prohibitive for me right now.....
> >
> > Regards
> > Bill G
> >
>
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