DSLR Trigger Help

  • 'Switch:' lists COM ports that are available. Take a test shot to check it is the correct port. If you attempted to use the GPS U-blox7 virtual COM port you must restart DSLR Trigger.
  • Progress is displayed as (number of shots taken) / (total number to take.) 
  • The 'Start after:' row is initialized to the current time. If set to the future, after pressing 'Start', the sequence will start at the specified time. If set to the past the sequence starts straight away.
  • 'Exposure / s:' Set this to exposure length. Minimum value 0.01 seconds. In Bulb mode this sets the exposure time. In all other camera modes, this field's value must be equal or greater than the camera's shutter speed.
  • 'Bulb mode' Select if the camera is in Bulb Mode. Bulb mode is strongly recommended. It can improve exposure end time accuracy, and allows a sequence to be aborted without having to wait for a long exposure to finish.
  • 'Fire interval / s:' is the time from the start of the first shot to the start of the next shot. Note that if the camera starts buffering images, the shutter lag may become inconsistent. Ensure that:
'Fire interval' time    >    'Mirror Lock' time + 'Exposure' time + '0.25 seconds'.
  • 'Shots:' Set to the desired number of shots or set to a high number and use 'Stop' to end the sequence.
  • 'Single test shot': if selected, the 'Start' button will take a single shot straight away. The 'Start after' and 'Shots' settings are then ignored.
  • 'Mirror Lock' Tick this option if the camera is in mirror lock mode. Mirror lock can significantly reduce the shutter open lag and make it more consistent. Look for Mirror Lock in the camera's custom menu.
  • 'Mirror Lock / ms:' If the 'Mirror Lock' option is ticked, this field sets the number of seconds to flip the mirror up before the shot is taken. Minimum mirror up time is 1.0 seconds. The Mirror lock feature works with cameras that use the first button press to flip up the mirror and the second to take the shot. Take care that the 'mirror up' / 'take shot' button presses do not get out of sync. If 'Mirror Lock' is not ticked, the 'Mirror Lock / ms:' value is ignored.
  • Log folder: Use the '...' button to navigate to a new log file folder.
  • 'Filename:' The log file prefix. For example 'RemoveDebris', 'ISS', 'DARK', 'BIAS'. Its only affect is to prefix the log file name. The log file also uses the current time to make the filename unique.
  • Log file columns include:" +
'ML press' Time the button was pressed; instructs DSLR to lock up mirror.
'ML release' Time the button was released; mirror stays locked up.
'SB press' Time the button was pressed; instructs DSLR to take an image.
'SB release' Time the button was released; if in bulb mode, instruct DSLR to end exposure.
'Start time' The exposure start time; equal to 'SB press' + 'Shutter open delay'.
'End time' The exposure end time; equal to 'SB release' + 'Shutter close delay'.
'Exposure' The exposure time; equal to 'End time' - 'Start time'.
'Comment' BST / GMT, aborted image details.
  • DSLRtrigger tries to ensure that the exposure 'Start time' starts at an exact second. To do this, the shutter button is pressed early (by 'Shutter open delay'). However, due to OS multitasking, there may be a delay. The actual times the buttons are pressed are recorded in the log file. Shutter lag can be reduced by using Mirror Lock and either 'Manual' or 'Bulb' mode, with auto focus off.
  • 'Settings' Displays the 'DSLR Trigger Settings' dialog.

  • 'Shutter open delay compensation' Press the shutter button early by this number of ms to compensate for shutter lag.
  • 'Shutter close delay compensation' Release the shutter button early by this number of ms to compensate for shutter lag. The 'Shutter close delay' only has an effect in Bulb mode.
  • 'Tab separated data' If selected, the log file columns will be separated with a tab instead of a comma character
  • 'Log all events' If selected, all button press and release times will be logged.
  • 'Calibrate' displays a dialog used to determine the DSLR's shutter open lag times.

  • Why are all my exposures equal to half the mirror up time instead of the exposure time?
This can occur when using mirror lock if the 'mirror lock' / 'shutter button' presses have got out of sync. The image will be taken at the 'ML press' time instead of the 'SB press' time, so the logged times will also be wrong.

  • I asked for 5 shots, but 10 were taken. The odd number shots were incorrectly exposed for half the mirror lock time.
This can occur if DSLTrigger is set to use 'Mirror Lock' but 'Mirror Lock' has not been set on the camera.

  • How can I take a series of shots with exposures less than 0.01 seconds?
Set the camera to use 'Manual' instead of 'Bulb' mode. In DSLR Trigger, untick 'Bulb mode'.
Set the DSLR Trigger exposure to 0.01 seconds. Set a shorter exposure on the camera.
Note that it is essential that the camera shutter speed is never longer than the exposure time set in DSLR Trigger.