1 The Director of Photography – an overview

Three-point image control 113
Point 3
We know that the chosen film in this example has a tonal range of the
equivalent of seven stops and therefore will record up to three stops
of information above the setting for the 18 per cent grey card. As we
have established that the lens is to be set at T4, then this upper cut-off
point will be a reading of T11, three stops above T4.
Now explore the highlights in your scene. Any parts of the scene
that read below T11 will have information in them; any that read above
T11 will appear in the cinema as even, clear, white.
There is one more matter to remember when reading the highlights.
When you get a reading a certain amount above the maximum recordable
by the film, the image of that subject will grow, as pouring so much
energy, light, into the film’s emulsion causes it to disperse in various
ways. Also, there is a likelihood of lens flare at these very high brightnesses.
Containing this overexposure within two stops above the maximum
recordable will usually prevent this happening.
Relating the three points to the sensitometric curve
Let us assume we are about to photograph an exterior scene with a
200 ISO film we have used before and we know its characteristics
quite well. Experience tells us that with this film we will be able to
record a seven-stop tonal range and that we will still get a little detail
in the highlights if they are three stops brighter than the aperture we
have set on the camera, and we still get just a little detail in the
shadows when they read four stops below camera aperture.
Figure 12.1 shows a scene with the viewfinder image of a Pentax
Digital Spotmeter overlaid on the scene. Let us say we were using our
200 ASA film, then the reading on the girl’s face, Point 1, would be 8 in
the viewfinder.Translating this on the meter’s scale, this becomes T5.6.
We would therefore set the lens to T4, as her skin tone will be reflecting
about one stop more than an 18 per cent grey card.This means that
camera aperture would now be represented by a reading of 7 in the
Pentax viewfinder.
Checking the doorway to the right of the building, the shadow, and
therefore Point 2, we get a reading of 4 and one dot in the viewfinder –
that is, two and two-thirds stops below camera aperture and therefore
one-third of a stop above black. Converting this to an exposure we get
T1.0; therefore, the doorway will be just on the very edge of having
information in the image and the door will, most likely, have wood
grain just discernible in the image.
A reading taken on the highlight on the wall just below the dome on
the top of the building is 9 and two dots in the viewfinder. As each dot
in a Pentax finder represents one-third of a stop, this gives us a reading
two and two-thirds stops above the camera aperture, still one-third
of a stop within the three-stop limit, so there will still be a little colour
and detail in these highlights – they will not have lost information or
become pure white.
All the other tones
It is now possible to take readings from any or all the other tones and
see exactly where they are going to sit within or outside the tonal range