31
Depth-of-field calculation 7
There are two distance scales (in feet and metres) visible through
the focus distance window on the upper part of the lens barrel.
There is also a central lens index mark and a depth-of-field scale.
The focusing distance is read off the chosen scale from the central
lens index.
Depth-of-field can be calculated as follows:
1. Focus the lens as required.
2. Make an exposure reading (auto or manual) and note the
aperture setting.
3. Find the markings on either side of the central index that cor-
respond to the chosen aperture.
4. From these two markings, read off on the required lens dis-
tance scale the two corresponding distances.
5. The depth-of-field (at that particular aperture and focus set-
ting) will be the area included between these two distances.
In the example given here, the focusing distance is set at nearly 3
metres. At an aperture of f/22, the depth-of-field would therefore
extend from just over 2 m to approx... 4.5 m.
Stop down /depth-of-field 8
A visual depth-of-field preview can be made by depressing the
STOP
DOWN
button while viewing the image on the viewfinder screen.
Infrared focus settings 9
As infrared rays form an image at a different plane to that formed
by visible light, the normal focus settings do not apply. Proceed as
follows in manual focus mode:
1. Focus the lens in the conventional manner until satisfied.
2. Note the distance setting against the central lens index.
3. Re-align this distance setting against the infrared mark
(coloured red) instead of the central lens index.
Alternatively if you have already calculated the required distance,
you can make a manual distance setting by using the distance
scales together with the infrared mark instead of the central lens
index.
Focus aid
As well as the conventional view on the focusing screen to ensure a
sharp image, the H2 also features LED focus aid appearing as two
arrowheads to the right of the viewfinder display (except for lenses
with a maximum aperture of f/6.7 or smaller). The arrowheads
provide confirmation of a precision focus setting and are a useful
aid when making a setting with eyesight alone.
Manual focus setting
When the left arrowhead alone appears it means the focus setting
is too far beyond the chosen distance (the area framed within the
central zone in the viewfinder) and when the right arrowhead
alone appears it means the focus setting is too close. Focus is cor-
rect when both arrowheads appear together. If the focus cannot
be established, then both arrowheads flash.
Automatic focus setting
Focus is correct when both arrowheads are visible together. Focus
7
8
9
10
Lens focus setting too far
beyond the distance of the
subject framed by the central
section in the viewfinder
11
Focus setting too close for
the distance of the subject
framed by the central section
in the viewfinder
12
Focus setting correct
