On 25 Jan 99 at 14:09, Sean Chan wrote:
> Probably the wrong place to ask this question but I find you guys
> and gals a lot more friendly than the newsgroup or EOS mailing
> list (you should see the kind of arguments going on there).
Actually, I think it's a useful topic for discussion...
> Anyway, back to my viewfinder question. My OM-4Ti specs state 97%
> 0.86x, whilst my EOS-3 states
> 9700000000000000000000000000000000000000000000000000000000000000000000000000
> (or some smaller mag).
> Looking through the viewfinders of both with a 135mm lens, the
> subject in the OM-4Ti looks a lot bigger/closer than the EOS-3.
> Presumably due to the magnification issue. What does 97% mean
> then?? 970f what I see in the viewfinder??
>
> But that doesn't make sense 'cos if (hypothetically speaking)
> both the OM-4Ti and EOS-3 had a 100% viewfinder and both had
> the same focal length lens, and the only difference is the
> 0.74X vs. 0.86X magnification, the image on the neg of the
> EOS-3 would cover more viewing area than the OM-4Ti!! Wouldn't
> one expect that a 135mm focal length lens would give the same
> coverage on the negative regardless of body and viewfinder
> (afterall, when the subject is imaged onto the negative, the
> viewfinder plays no part during the exposure process).
>
This is my understanding of it:
The 97% means you will see 970f the image recorded on the 24x36mm negative
frame. The magnification factor is usually indicated with a 50mm lens, and
indicates the visual magnification without diopter adjustments. ie: The EOS3
probably needs a smaller image in order to fit the additional viewfinder info
in.
Which brings me to another question: Does a "high eyepoint" VF equate to a
smaller image magnification? I ask this because our photo teacher (who wears
glasses) tried my 4T with and without glasses, and found that he could not see
the whole frame, which he can with his Nikon F90X. Two things to note: The
lower mag = smaller image in the VF, and the quite low 92 overage. This last
point surprised me, as I thought full frame coverage was one of Nikon's
features...
Here's the specs for the F90X:
Fixed eyelevel penta-prism high-eyepoint type; 0.78X magnification with 50mm
lens set at infinity;
approx. 92 0.000000rame coverage
========================
Shawn Wright
Computer Systems Manager
Shawnigan Lake School
250-743-6240
swright@xxxxxxxxx
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