Hasselblad H4D 40 - Depth-Of-Field Calculation; Depth-Of-F Ield; Visual Preview; Infrared Focus Settings; Focus Assist

29
H4D
7
8
9
10
Lens focus setting
too far beyond
the distance
of the subject
framed by the
central section in
the viewnder
11
Focus setting
too close for the
distance of the
subject framed by
the central section
in the viewnder
12
Focus setting
correct
Depth-of-eld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-eld scale. The focusing distance is read o the chosen scale from the central
lens index.
Depth-of-eld 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 correspond to the chosen
aperture.
4. From these two markings, read o on the required lens distance scale the two cor-
responding distances.
5. The depth-of-eld (at that particular aperture and focus setting) 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-eld would therefore extend from just over 2 m to approximately
4.5 m. Note that depth of eld is not an absolute. Perception of it depends on several
factors and so it should be seen only as a rough guide.
Stopdown/depth-of-eld 8
A visual depth-of-eld preview can be made by depressing the STOP DOWN button while
viewing the image on the viewnder screen.
Infraredfocussettings 9
As infrared rays form an image at a dierent 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 satised.
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 man-
ual distance setting by using the distance scales together with the infrared mark instead
of the central lens index.
For specialists, please contact your Hasselblad dealer for information about digital cap-
ture units adapted solely for infrared photography.
Focusassist 10,11,12
As well as the conventional view on the focusing screen to ensure a sharp image, the
H4D also features an LED focus aid capability appearing as two arrowheads to the right
of the viewnder display (except for lenses with a maximum aperture of f/6.7 or smaller).
The arrowheads provide conrmation 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 viewnder) 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 ash.
Automatic focus setting
Focus is correct when both arrowheads are visible together. Focus is incorrect if only one
arrowhead is visible. If the focus cannot be established, then both arrowheads ash.