Hugo Lopes wrote:
>
> I don't know if this really has much to do with tolerances. After
> exchanging a few mails with Jonathan Kwok, I came to the conclusion that
> the off-centered focusing points might well be poor quality control.
I am somewhat doubtful; since the apparent alignment has no affect on
the camera's operation, some sight deviation from dead-center is
probably within the QC tolerances Canon set for these products. FWIW,
the focusing points in my EOS 3 were nicely aligned until I had the
camera serviced by Canon's facility in New Jersey; they now appear
skewed to the right ever so slightly. I infer from this that they can
relatively easily be knocked off center relative to the eyepiece and
focusing screen. Certainly the diagram in the EOS 3 Technical Overview
indicates the mechanism for projecting the focusing points directly
through the eyepiece lens by means of a couple dichroic mirrors (they
only *appear* to be on the focusing screen) is fairly complex, and I
suppose if one of the dichroic mirrors was nudged the positioning of the
focusing points when seen through the viewfinder could be affected.
However, in as much as one suggested fix was to reinsert the focusing
screen (which had little effect in my case), it seems to me the
positioning of the focusing screen could well be the culprit, since that
mechanism seems not to be particularly precise. In any case, as a Canon
tech remarked to me, it is a slight annoyance but merely cosmetic.
In terms of tolerances, with my particular 3 the big problem is the
flash shoe, which is not level relative to the horizontal plane of the
film--if I use a bubble level, my photos all lean to the left!
>
> focusing system of the EOS 3 and 1V required these small tolerances to
> work properly, Canon should have thought of it before making the
> cameras. It seems that they didin't foresee these problems.
Well, it's not as though the camera doesn't work properly if the
focusing points projected through the eyepiece appear slightly
off-center. Keep in mind that while these are precision devices
(relatively speaking), they are also mass-produced consumer goods, not
hand-made precision instruments. Think of what they would cost if
completely hand-built to very tight tolerances! It is not at all
analogous, IMO, to a square steering wheel in a car, which would of
course make the car difficult (and unsafe) to drive. Personally
speaking, I stopped noticing the off-center focus points after a week or
two of using the camera, and I notice even less now that I use the grid
screen. If we want to talk about design flaws, the EOS 5 command dial is
a much better candidate. :-)
fcc
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