Intervalometer for Canon and Nikon cameras

Step 10 Intervalometer operation

There are 4 buttons on the intervalometer.  Up, Down, Enter, and Trigger. 

Up - move backwards in the menu structure, or if at item level, increase value.
Down - Move forewards in the menu structure, or if at item level, decrease value.
Enter/Sel - Select the current menu item, or at item level, change value.

Trigger - Trigger is used to initiate each function.  When Interval, Sensor, or Manual are selected, Trigger causes the unit to execute the function based on the settings that were made to the unit.  For instance, in Sensor mode, once the edge is chosen and the threshold is selected, pressing Trigger will cause the CT-1 to start looking at the sensor input and triggering the camera based on the current readings.  In Setup mode, the Trigger button has no function.



The menu structure is shown below.  There's four main menu items:
Interval - Intervalometer functions.  Set exposure and delay and take a series of pictures.
Sensor - Use the built-in phototransistor to detect changes in lighting and take pictures
Manual - Use the unit as a simple remote device
Setup - Setup functions

Interval menu
The interval menu is use to access and set the exposure and delay timers for the unit.  Items in this menu are:

• DlyUnits - This sets the units of measure for the delay portion of the intervalometer - either seconds or minutes.
• Delay - Amount of time for the delay, of course based on DlyUnits.
• ExpUnits - Exposure units (min/sec)
• Expose - Amount of time for the exposure - in ExpUnits.

Once the four items are selected and set, press the Trigger button to start taking pictures.  The CT-1 will take pictures until any button on the unit is pressed - causing it to stop.  When the unit is triggered, the display will show 3 different values (see the picture below).  The D value is the delay between frames - the E value is the exposure time, and the F value is the frame counter.

Note: Generally exposure is controlled on the camera, so 0.2 second exposure time (default) is sufficient to trigger the camera.  If exposure control from the CT-1 is desired, the camera must be in bulb exposure mode.

Note: Autofocus should probably be OFF on the camera.  The CT-1 will turn on the focus output to the camera, but in general if Autofocus is On in the camera, you'll have two undesired effects.  First, the camera will take a long time to set focus, potentially missing the exposure.  Second, each frame taken in the sequence will potentially have a different focus point.

Sensor menu
The sensor menu allows use of either the built-in photo (light) sensor, or an external sensor that is plugged into the 2.5mm sensor input on the side of the unit.  Items in this menu are:

• SensVal - Current value of the sensor input. This is an analog input channel that ranges from 0 to 255.  Not changable - expect of course by changing the light hitting the sensor.
• Edge - Lets you select the edge that will cause the unit to trigger. Choices are Rise and Fall.
• Thrshld - This is the threshold value - it sets the sensitivity of the unit.  When the SensVal crosses the Thrshld value in the Edge direction, the camera will be triggered.

Once Edge and Thrshld are set as desired, press the trigger button all the way to enable the active sensor mode.  The screen will change to show what's happening - see the picture below.  It shows the current SensVal, the Threshold, and an arrow pointing up or down depending on the Edge that was chosen.

Example: Say your camera is set up such that it's in the sun, and you want to take a picture when a shadow obscures the sun.  In direct sun, you see that SensVal is 240.  When you block the sun, SensVal drops to 100.  In order to set up the unit, you'd want to set the Edge to Fall (we want to take the picture at the moment that the sun is blocked), and set Thrshld to around 200.  This way, when the sun is blocked, SensVal will drop from 240 to 100, and as it passes 200, a picture will be taken.

Note: For sensor mode, Autofocus should be disabled as it will generally cause a delay in taking the picture, likely missing the event that you wish to capture.

Note: Consider using Mirror lockup when in sensor mode (see the setup menu).


Manual menu
The manual menu allows two options that make the CT-1 more like a simple switch trigger.

• Remote - Choose this mode and when you press the trigger button, it acts like a simple remote.  Press the Trigger button 1/2 way, it focuses, press it all the way to take a picture.
• BulbTogl - This mode toggles the camera output.  When first initiated, press the Trigger button 1/2 way, and the camera will focus, press the Trigger completely, and the camera shutter will open.  Press the Trigger again, and the shutter will close.  The camera must be in bulb mode for this function to work correctly.

Setup menu

• MirrorLU - Use this option to set mirror lockup mode on or off in the CT-1.  Note that you need to turn mirror lockup on or off accordingly in the camera to match the CT-1 setting.  Mirror lockup allows the camera to work in two stages.  Stage 1 is to lock up the mirror, stage two is to open the shutter.  Normally these stages happen concurrently.  With mirror lockup mode, they happen separately.  There's a couple uses for this mode:
  • Long-distance shots where the mirror movement will affect the stability of the shot
  • Capturing events that happen very quickly - eliminating the mirror movement speeds the camera's response.
• FocMaint - Tells CT-1 whether to maintain the focus output to the camera during intervalometer or sensor mode.  Since it's recommended that Autofocus be turned off during these functions, FocMaint should generally be set to Off.
• ClkAdj - Allows you to make small adjustments to the system clock.  In general it's accurate enough for most work, but if you need more precision, this is the place to set it.
• Contrast - Sets the contrast of the LCD screen.
• BkLight - Sets the backlight mode.  Choices are On, Off, and 15 seconds.