Leica M Instruction Manual page 69

LINEAR FLASH MODE (HIGH SPEED SYNCHRONIZATION)
Fully automatic, i.e. camera controlled, linear flash operation is
available with the Leica M when using the Leica SF 58 flash unit, with
all shutter speeds and in aperture priority and manual exposure
modes. The camera activates it automatically if the selected or
calculated shutter speed is faster than the sync speed, i.e. ≤
the flash unit is set correctly, this change does not require the
photographer to do anything else.
Important:
The range for HSS flash is significantly lower than for TTL flash.
SELECTING THE SYNC SPEED / THE SYNC SPEED RANGE
Reproduction of the available light is determined by the shutter speed
and the aperture. A fixed setting to the fastest possible shutter speed
for flash operation, the sync time, leads unnecessarily in many
situations to a greater or lesser underexposure of all parts of the
subject not directly lit by the flash.
The Leica M allows you to combine flash operation with the shutter
speed generated in aperture priority mode to subtly change the
lighting conditions for the relevant subject to suit your compositional
ideas. You can choose any of five ways of doing this:
Setting the function
1. In the main menu (see p. 154/246),
section), and
CAMERA
2. Select the automatic lens-specific setting -
whether you want to specify a particular shutter speed yourself -
/ s. If Manual setting - in the sub-menu.
1
180
3. In the Manual setting sub-menu, set the range of shutter speeds
permitted by specifying the fastest speed permitted.
Notes:
1/Focal length
rule of thumb for blur-free pictures taken from the hand, e.g.
with a 50mm lens. However, in the
limited to /
1
125
The setting field in the
current slowest shutter speed setting.
Manual exposure control also allows any shutter speed up to the
sync speed /
1
If the Leica SF 58 (see p. 190) is being used and faster shutter
speeds are set on the camera, i.e. ≤
automatically switches to HSS mode.
Only when using Leica M lenses with 6-bit coding in the bayonet and lens
1
identification enabled in the menu.
194
Auto Slow Sync.
results in the slowest shutter speeds based on the
Auto Slow Sync.
s, even if the focal length used is longer.
sub-menu initially shows the
Manual setting
s to be set.
180
/ s, the flash unit
1
180
(page 1,
, or
1
1/Focal length
/ s
1
60
menu it is