Using the time-lapse (intervalometer) feature

The time-lapse feature has many parameters that at first glance may seem intimidating.
A very powerful way of using time_lapse is to simply follow the command with a single parameter that denotes the parameter-set (0 to 9) that you wish to use.
All the parameters described below should then be defined in your parameter-set, together with a four-line description.

Time_lapse operation is simple, once you decide what you want to do.
It is only necessary to change parameters that are relevant to your intended use, SDM will ignore the others.
Normally, time_lapse.bas is your default script, if not then load it now.

After reading this section and running the time-lapse script with the provided default values, try working through the examples described in the section 'Testing the time-lapse (intervalometer) feature'.

Now, let us examine the default parameters :

time_lapse a, b, c, d, e, f, g, h, i, j, k, l, m, n, p, q, r, s, t, u

@param a first delay minutes
@default a 0
@param b first delay seconds
@default b 10

Parameters 'a' and 'b' set the delay time before the sequence begins.
Default is ten seconds.

@param c shoot interval minutes
@default c 0
@param d shoot interval seconds
@default d 5

This is the time-interval between each capture 'repeat'.
We are using the word 'repeat' to describe capture of a single image or bracketed series of images, whatever you require.
The default value is a five second interval between repeats.

If the time-interval is set too short for the shooting situation, the sequence may not terminate.

@param e number of repeats
@default e 3

The number of times you want to repeat the capture of a single image or bracketed sequence of images.

@param f endless mode N/Y 0/1
@default f 0

Instead of the above number of repeats, you may wish the capture to continue indefinitely until the script is halted.
Enter '1' for that option (parameter 'e' will be ignored).

@param g single/cont/time/burst
@default g 0

Each repeat can be a single image, enter '0' for that.
If each repeat is a bracketed sequence, the camera needs to be in continuous-shooting mode (enter '1') or custom-timer mode (enter '2').
Note that the number of images with custom-timer is determined by the value in its menu, not parameters 'h' or 'i'.
Nevertheless, parameters 'h' or 'i' should be set to same value as in custom timer as they are used by SDM.
It is also possible to take a number of images as fast as your camera continuous-shooting mode will allow.
Set the camera to continuous-shooting mode
For that option, enter '3' for 'burst' mode.
If you set the number of repeats (parameter 'e')to '0', the burst will last for the 'shoot interval seconds' value.
Otherwise, the number of images captured will be the value entered in 'number of repeats'.

@param h Tv exposures
@default h 3

In a bracketed capture, this is the number of shutter-speed (Tv) bracketing shots.
For example, every 30 seconds you may take five Tv-bracketed exposures.

@param i Focus exposures
@default i 3

In a bracketed capture, this is the number of focus-bracketed shots.

@param j bracket Tv/foc/Both 0/2
@default j 0

If bracketing, we have set parameter 'g' to continuous or custom timer and have set parameters 'h' and 'i' to required values.
Now, we specify if we want Tv bracketing (0), focus bracketing (1) or both (2).
If we choose both, multiple focus stacks at different exposures will be created at every repeat interval.
If we have set focus exposures to 5 and Tv exposures to 3, a focus-stack of five exposures will be captured at a certain speed and then repeated twice more at other shutter speeds.
Note that the camera must be in a mode that allows focus-override.

@param k light/dark/alternate 0/1/2
@default k 2

In continuous-shooting Tv bracketing, the exposure alternates each side of the starting value.
With custom-timer Tv bracketing the exposure can make the image lighter (0), darker (1) or alternating (2).

@param l num of 1/3 EV steps
@default l 3

For Tv bracketing, this is the size of each bracketing step in units of 1/3EV.
Three EV is equivalent to one f-stop.

@param m equal/auto/digi 0-2
@default m 0

There are three types of focus bracketing.
You can have equal-step (0), automatically-calculated steps (1) or a special digiscoping (2) mode.
Be aware that the auto function captures however many images are required to reach infinity from the starting focus.
For extreme close-ups at a telephoto setting, this could be a large number of images.
You should first try one repeat, the time to capture the stack will be indicated.
Use that as a guide to possible repeat intervals.
With digiscoping, the camera is attached to a spotting telescope and focused on the virtual image.
This option allows you to capture a number of images each side of the reference-focus position.
The camera will zoom to the position defined in the digiscoping menu.

@param n focus-step
@default n 50

The size of the focus-step to be used in equal-step and digiscope focus bracketing.

@param p digiscope focus ref
@default p 500

The camera focuses on the virtual image at this distance for digiscoping.

@param q blank screen N/Y 0/1
@default q 0

Many photographers like to blank the screen for long time-lapse sequences, often using a 2.5 to 3mm wooden dowel inserted in the camera's A/V socket.
An alternative is to enter '1' with this option.
The LCD backlight will be turned-off and only very briefly turns-on after each exposure.

@param r shutdown N/Auto/USB 0/1/2
@default r 0

The camera may shut-down automatically after the required number of exposures (1) or when a USB V+ signal is received (2).
Typically, the signal could be from a wireless receiver.
In that mode, the time-lapse is also started by a USB V+ signal.

@param s save stack N/Y 0/1
@default s 0

Enter '1' to save the bracketed values to a log file.
The file will be in folder CHDK/STACKS.

@param t Sunrise mode
@default t 0

If this option is checked, the number of images to be captured is as set in the Advanced/Experimental Sunrise menu.
The exposure for each image is also determined by the settings in that menu and consists of three non-linear exposure-change phases followed by constant exposure.
This mode is free-running (that is, it does not require external USB pulses that are used for multiple-camera shooting).
@param u TXT/CSV 0/1
@default u 0

If you have chosen the option above to log data to a file, for sunrise mode you can choose to save to a text file or, for brightness and luminance values, to a CSV file for spreadsheet analysis.
Knowledge of how the scene brightness changes helps you to devise an exposure strategy.

So, it is really quite simple, do you wish to take ......

a fixed number of images at a regular time interval ?
an indefinte number of images until capture is interrupted ?
a fixed number of images as quickly as possible in a 'burst' ?
as many images as possible in a fixed duration burst ?
a fixed number of repeat captures, each capture Tv, focus or Tv and focus bracketing ?
a sunrise/sunset using variable, very small changes of exposure

Now that you know all of that and assuming the camera is in single-shot mode, press the shutter button to start the default time-lapse script.

After focus has been attained and locked, three images at five second intervals will be taken.
On completion, a message is displayed and the blue LED flashes.