:> The OM-4 manual (page A-63) claims -5 EV ~ 19 EV for average light mode
:> and -7 EV ~ 19 EV for spot mode.
:> The OM-4Ti manual (page 130) claims +(sic!)5 EV ~ 19 EV for average light
:> mode and 0 EV ~ 19 EV for spot mode.
:
:Yes, I verified my 4T manual makes the latter claim. But it's gotta be
:a mistake. I believe they switched 'em.
They haven't switched them. The data from the 'old' manual are the right
ones. This '0 EV - 19 EV' spec corresponds to the measuring range of the
OM-3 (yes I have that manual too). In Manual Mode, these data make sense: 1
sec is longest pre-set time available.
:Theory: To me, this makes sense. In spot mode, you take a direct,
:immediate reading of a light level. If that light level is 'low' can a
:millisecond spot reading possibly give an accurate reading? I mean this
:relative to the OTF auto metering, which works by *integrating* the
:light over the entire scene over time. This integration process allows
:much finer and I believe lower light levels to be measured.
:I'm interested in hearing your experience in this subject, Hans.
I believe the OM-4 and the OM-4Ti differ in the way they handle AE control
by average light when average light yields shutter speeds beyond the
measuring range of 1 minute. The OM-4 just locks up, no matter how many
light you add to the scene (flash, wide open aperture, point it to a light
source). Resetting is the only remedy. The 4Ti will free the mirrot and the
shutter after...probably 4 minutes? I think you were just lucky with these
night scenes in Auto mode w/o spot metering, and that the spot tests you did
were probably just aimed at the wrong targets - only at the highlights. I've
done some succesful night scenes *with* spot metering, also shots that
resulted in times larger than 1 minute. I always do a *multi* spot - one at
the highlights (for instance when there are lamps in a street scene), a few
at intermediate lit surfaces (for instance walls lit by the lamps) and one
or two at the sky. But such scenes are difficult and there will always be a
luck factor. 'Auto-bracketing' (ahem) with the aid of the exposure
compensation dial (or leave AE and use the Bulb setting) can help.
Hans
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