In SMS mode, I'm having trouble with my motors moving during the exposure?

It is very important to fully understand each MX2 / MX3 / NMX interval cycle is ALWAYS a sequence of events. At start or at each external trigger event, the cycle repeats:

The Interval is the sum of:

1. Focus Time (MX3:Camera>Focus>)

  • This is essentially like a trigger 'half press' on your camera causing the autofocus to become active. In most cases it's best to have your auto-focus off but this setting can be useful when using Live-View (or auto-review) settings, or to 'wake' your camera if your interval is long enough that the camera goes to a sleep mode.    

2. Trigger Time (MX3:Camera>Exp. Time>)

  • This is essentially 'full pressing' your trigger on your camera causing an exposure. In most cases 100ms is enough time to trigger the exposure. This setting can also be used to set a Blub Exposure (by setting the camera to Bulb Mode) or when using the camera's AEB (auto exposure bracketing) for HDR. For AEB you would set the trigger time long enough to fire off all of the brackets (this will vary depending on the AEB exposures set)

3. Motor Delay Time (MX3:Camera>Exp. Delay>)

  • This is a set duration time AFTER the Trigger Time and BEFORE the motors move, in general you want set this setting a little longer than your set exposure but *see the VERY IMPORTANT NOTE below.  

4. Motor Movement Time (note: the longer the motor move the longer this takes)

5. Buffer Time

  • This is the excess time, if the interval is longer than all the above this excess time will be dumped into the buffer time.

If you are using longer exposures, the setting to concentrate on is #3 the Exposure Delay. You'll need to set the exposure delay LONGER than your exposure time set on the camera. So for example if your camera is set to 10 second exposures then you'll want to set the exposure delay to about 11.5 seconds or 11500 ms (1000ms = 1 second).

*VERY IMPORTANT NOTE: be aware due to the rule of reciprocity the camera exposure setting is not 100% accurate! Camera manufacturers have always rounded off exposure times, the longer the exposure the further off it will be! The actual exposure time for a 30 second exposure is closer to 32.5 seconds!  (use a stopwatch to time it and you will see the truth for yourself!)

If there is no room for buffer time (in other words the camera seems to be firing too close to the end of the motor move), this problem can be resolved by setting the Focus Time a little higher to give the system time to settle before firing the camera. There is a built-in 100ms delay between the end and the beginning of the loop, but that's so quick it may appear that the motor is still moving when the camera fires.

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