On 30 Apr 02 at 22:32, Willem-Jan Markerink wrote:
> On 30 Apr 02 at 13:48, [EMAIL PROTECTED] wrote:
> > "Neil K." wrote:
> >
> > > Actually, Julian Loke and Gerard Maas have written an interesting
> > > and detailed article for the EOSDoc Web site about this, not me.
> > >
> > > http://www.eosdoc.com/manuals.asp?q=E7EMFlens
> > >
> > > They say that their tests lead them to believe that the Elan 7/EOS
> > > 30/33 consistently meters out by 3 stops and that (I think) this is a
> > > linear error. However, I've been contacted by at least one other
> > > person who claims that the error is non-linear.
> >
> > Neil,
> >
> > Do you know which lens this person was using? Does it works on other EOS
> > bodies?
> >
> > I did many test with different manual lenses.
> > - The "mystic" EOS-FD adaptor and a 135f/3.5 FD
> > - The 135/3.5 and 50f/1.8FD on a FL bellows and an a hand-made FD-EOS
> > Macro adapter (no glass)
> > - The Macrophoto 35f/2.8 with the previously described bellows & adaptor
> > - Undocked EF100f/2.8 (you just don't click the lens on the mount, so
> > there's no electronic communication)
> > - ... and the Zenitar 16mm fisheye.
> >
> > All of them showed a linear difference of 3 stops tested by photographing
> > a kodak gray card and comparing with a slide of the same card photographed
> > with the 100f/2.8 USM and the EOS 30.
>
> Try a 1000mm/f10.5 mirror, and you'll end up with 7 stops....:))
> My rule is <difference between <f1.0> and <max F-stop lens>>.
> Additional problem with 7 stops is that you run out of compensation
> with 50 ASA film....3 stops per ordinary +/- correction, 2 stops per
> ASA-correction (12 ASA is minimum, on itself a lousy spec; with
> infrared film and very strong filters you end up with fractions of
> ASA; if not for auto-exposure, at least in manual mode (with exposure
> information in the viewfinder)).
Please note that this experience is based on the (fine)spotmeter in the EOS
1(n (RS)), but seeing the same values for the 30/33/7 I assume it is
the same structural problem.
Which leads me to another question, related to the 1n-RS:
In a recent thread on de.rec.fotografie someone asked how the non-RS
viewfinder-screens should be compensated, as they are 1 stop less
bright than the special RS-screen.
This seems an easy question (dial in 1 stop overexposure), but it's
definately not, since the same finespotmeter in the bottom of the
mirror-box spoils things....it sees the same amount of light,
regardless of screen.
Add matrix-mode, which includes the finespot sensor, and things get
even more confused....
I vaguely even recall a (S?)CF option which would compensate for
non-RS screens, but other than that, shouldn't Canon Service be
capable of recalibrating this camera?
--
Bye,
Willem-Jan Markerink
The desire to understand
is sometimes far less intelligent than
the inability to understand
<[EMAIL PROTECTED]>
[note: 'a-one' & 'en-el'!]
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