John;
I think there are some misconceptions below.
John Hudson wrote:
>
> Pages 81 thru 84 of my 6" by 4" OM4T instruction book covers the camera's
> highlight and shadow control metering features. The highlight example
> features three all white pieces of table crockery against an off white
> background and the shadow control features an all black telephone against a
> grey background.
>
> As an experiment I took a spot reading with my camera from a distance of
> about four feet of the non-polished black leather of an easy chair using 100
> ISO film under fairly bright but cloudy lighting conditions. The reading was
> 1/30 @ f2.8. The same reading was confirmed by a 15 degree spot reading with
> a Lunasix 3 hand held meter.
>
> When I re-spot metered with the camera and then pressed the shadow control
> button the exposure reading changed to 1/200 @ f2.8 which would result in a
> photo of a darker shade of black!
If the chair is black and you want it to look black, the shadow control
will do that for you. think of it this way: Your reading of 1/30 @f/2.8
by both meters is the correct reading IF the chairs' reflectance is that
of 80 0rey. IOW, if you take the picture at that exposure, you're
going to get a chair that doesn't look black, but probably will look
mid-to-dark grey.
If, however, you take the picture after pressing the shadow button, the
exposure will let in about 2 stops LESS light and the chair will look
.... black.
>
> I re-spot metered on the same chair and then pressed the highlight button
> and the exposure changed to 1/8 @ f2.8. Now this surprised me because I
> would have thought that for the highlight feature to work properly the
> camera's meter would have had to have sensed something white or highly light
> reflective. The longer exposure of 1/8 resulting from pressing the highlight
> button even though the normal spot metering showed 1/30 tells me that the
> highlight feature might be mimicking the characteristics of an incident
> light meter. However, in actuality, the mimicking in this case is false
> because the black leather is absorbing rather than reflecting light.
No,no,no. Answer same as above only in this case 2 stops MORE light
comes in, and the chair will look washed out.
The key point is that you must ONLY press the spot/shadow when you're
metering something quite dark and you want the subject to be dark in the
photo. and conversely ONLY do spot/hilite when your subject is quite
bright and you want it to be bright in the photo.
Another GREAT way to use the OM spot meter (especially with slide film)
is to 1) Point at the brightest area you want DETAIL, press spot. 2)
Point at the darkest (detail) area, press spot. The little triangles
will show the 2 readings and the actual exposure, which will be the
average of the 2. Now, you could press spot/hilite on bright area and
spot/shadow on dark but it won't make any difference, cause the average
will be the same. BTW, the #shutter speeds between the 2 readings = #evs
and can tell you if your subject has too wide a dynamic range to 'fit'
on the film. Rule of thumb: slide <= 5 evs, print <= 7evs.
Hope this helps
George
>
> I guess that my question is this: is the combined spot metering and
> highlight control feature an attempt to mimick the results of an incident
> light meter reading and if so how close would two sets of readings [one with
> an incident meter and the other using the OM4T spot & highlight feature]be
> in conditions when a straight reflected meter reading would produce false
> results ....... for example off snow or sand in bright sunny conditions
>
> Also, if the spot and shadow control exposure has the effect of mimicking
> an incident reading in reverse, so to speak, in cases where the subject
> matter absorbs as opposed to reflecting an excessive amount of light [like
> the black leather] I wonder whereabouts in the greyscale an off-black
> subject would have to be when the spot and shadow control exposure would
> match a straight spot reading.
>
> I have taken photographs of dark objects and have relied upon spot metering
> with my Lunasix 3 or my OM4T and the results have always been properly
> exposed. Now that I have run the spot and shadow control experiment using an
> admitedly dark subject [the black leather] and seen a jump in exposure from
> 1/30 to 1/200 at the same aperture I am wondering just how accurate the
> combined spot and shadow exposure feature really is..
>
> John Hudson
>
>
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