exposure
Leaf shutter
Leaf shutters are situated in the lens assembly of most medium-format and all large-format
cameras. They are constructed from a series of overlapping metal blades or leaves. When the
shutter is released the blades swing fully open for the designated period of time.
Focal plane shutter
A focal plane shutter is situated in the camera body directly in front of the image plane (where the
image is focused), hence the name. This system is used extensively in SLR cameras and a few
medium-format cameras. The system can be likened to two curtains, one opening and one closing
the shutter’s aperture or window. When the faster shutter speeds are used the second curtain
starts to close before the fi rst has fi nished opening. A narrow slit is moved over the image plane at
the fastest shutter speed. This precludes the use of high speed fl ash. If fl ash is used with the fast
shutter speeds only part of the frame is exposed.
The advantages of a focal plane shutter over a leaf shutter are:
~ fast shutter speeds in excess of 1/1000 second;
~ lenses are comparatively cheaper because they do not require shutter systems.
The disadvantage is:
~ limited fl ash synchronization speeds.
ACTIVITY 3
Create exposures of a stationary subject at a variety of shutter speeds between 1/125 and 1/4
second whilst hand holding your camera.
Set the lens to 50 mm (or equivalent) and correct the exposure using the aperture each time the
shutter speed is adjusted (use shutter priority [Tv] or manual mode).
At what shutter speed is the subject no longer sharp?Closed
Closed
AA
A
B
BB
Focal plane shutter fi ring faster than the fastest fl ash synchronization speed