Hans;
Hans van Veluwen wrote:
>
> :> 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?
My 4T doesn't do this. Depending on scene and aperture, I get varying
shutter speeds - up to a maximum of close to 4 minutes. Eg if F/2 gives
me 1.5 mins, F/2.8 will go for 3 min.
I think you were just lucky with these
> night scenes in Auto mode w/o spot metering,
Luck? I can always use some. But this isn't luck - it's tecnnology.
The 4T works great in averaging OTF mode for long exposures. I guarantee
it.
and that the spot tests you did
> were probably just aimed at the wrong targets - only at the highlights.
This could be true.
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.
This is a technique I regularly use in normally lit scenes, but haven't
at night. I'll take your advice and try it some time.
George
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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