Synchronised shooting using scripts (deprecated)

This information is provided for historical reasons only, SDM 1.60 and later do not require scripts for ordinary or flash shooting.

For testing, if you run the following script, every time you plug the USB cable into the PC (or press the button on a custom-built control) a photo will be taken :-

@title Twinned Remote button
wait_click 1
is_key k "remote"
if k=1 then shoot
goto "loop"

If it does not work, check you have the red wires connected to the +ve of the battery and also check the battery voltage.
Try inserting the USB plug into the PC.
This is fine for many applications but does not synchronise the cameras to the greatest possible extent !

Power-up both cameras individually (the timing is not important) and ensure all the settings are identical on both cameras.
Enable the synchronisation mode in the above menu.
This automatically enables scripting 'Remote enable' which is necessary for USB-status detection.
Assuming flash-synchronisation is not required, simply run the above script in both cameras :-

If we are in synch mode, by default the delay status will be shown at the top of the screen.
Even though the script is the same, the shooting-process acts differently.
On pressing the button, the blue LED's will light.
When both are lit, release the button and a highly-synchronised pair of images will be taken.
If you do not release the button after ten seconds, the process will time-out and the photo will be taken.
For action shots, press the USB-remote button and follow the action in the camera viewfinder.
You may then release the button anytime within the next ten seconds to capture a highly-synchronised shot.
Tests have shown average synchronisation up to 1/20,000 sec and the synch does not drift with time.

Instantaneous and delayed synchronised-flash is possible using the cameras internal flash and Tv mode.
Assume that the Left camera is designated as 'no flash' .
Although the start of shutter-opening in the cameras is very nearly simultaneous, we cannot know which will actually be the first.
We therefore delay the 'flash' camera by half the exposure-time so that the flash is triggered halfway through exposure.
If the shutter speed is 1/250sec (regarded as fast for stereo flash) that equals 1000/250 = 4 msec = 40 SDM fine-delay units (which are 100 micro-seconds).
Half of that is 20, so we need to 'Enable synch delay' and enter '20' in 'Synch fine delay 0.1ms'.

We also need to reduce the power of the 'no flash' camera so all of these operations are best incorporated into a script.
The script below (for the left camera) uses the 'set_sync' command to ensure that we are in synch mode and synch delay is disabled.
After running the script,the current delay-status will be shown at the top of the screen together with the delay value.
(you can change the position of any on-screen display element using the OSD Layout Editor).
For the left camera the value should be 0.0000 sec and for the right camera 0.0020 :-

@title Synch Test
@param a Synch enable
@default a 1

@param b Delay enable
@default b 0
@param c Fine (in 0.1ms)
@default c 1
@param d Coarse delay (in 0.1s)
@default d 0
@param e Flash EV -4 stops
@default e -384

rem get current flash override status
get_prop 28 f

> rem get flash on/off status (2 = closed, 1 = ON, 0 = Auto)
get_prop 16 g

set_sync a b c d

until (is_key "remote")

rem turn-down the flash on camera that has delay disabled but flash is ON (not Auto)
if b = 0 & g == 1 then set_prop 28 e

sleep 20

rem restore original flash override status
if b = 0 then set_prop 28 f
goto "loop"

On the Right camera, set script parameter 'b' to '1' and 'c' to '20' (for 1/250sec)

Adopt the same shooting procedure as above but BOTH flashes should be on !.
On pressing the button, both preflashes will fire to allow the cameras to determine white-balance.
Tests have so-far shown that the resulting white-balance is the same on both cameras.
On releasing the button, the left 'no flash' camera will instantly fire its flash at -4 stops below nominal level.
After a 2 msec delay, the right camera will fire its flash at full-power and illuminate both images (in the vast-majority of cases).
After acquiring the images, half-press the shutter to interrupt the script and ALT to return to normal menu mode.
You can try even faster shutter speeds if you enter the correct delay values.
There will be a few more failures but still a very high success rate.

After deciding what shutter-speed you prefer for flash, make a copy of the above script but with delay enabled and a suitable delay for the shutter-speed.
Install that in the camera that will be providing the main flash.

For convenience, the SDM download includes scripts for synchronised shooting.
For normal use, run 'Synch.bas' on both cameras
For flash, run 'Synch_L.bas' on left camera and 'Synch_R.bas' on right camera.
The flash scripts assume a shutter-speed of 1/250 sec, alter them if you wish.

It is possible to introduce a delay before making the synchronised-flash shot.
In this case, use the menu 'Synch coarse delay 0.1s' to enter a value up to 9 seconds on both cameras.
The value has to be the same on both cameras, of course.

(Minimum fine-delay is 0.0001 sec, hence in left image above value is 5.0001 sec).
It is best to use shorter values as the 'clocks' in both cameras do not run at exactly the same rate and you will need to 'tweak' the fine-delay value on the 'flash' camera.

Single-shot, delayed single-shot and continuous shooting-mode with external flash is possible using a circuit and script devised by Damir Vrancic.
In that case, the delay is achieved electronically rather than by using a coarse-delay SDM setting and there is obviously no need for a fine-delay 'tweaking'.

'Continuous-shooting synchronised-flash PCB