Making "GPS Power Safe" feature more customizable and therefore usable

[chris88]

I would suggest to make the GPS Power Safe feature more customizable and therefore usable.

Introduction:
There are several modes:

Mode 1: Normal Operation
Mode 2: Auto Power Off (timer)
Mode 3: Power Off (by physical pówer switch)

And between the modes there are several possible transitions.

Transition Mode 1 -> Mode 2 is timer based
Transition Mode 2 -> Mode 3 is done by the power switch
Transition Mode 1 -> Mode 3 is also done by the power switch

And also important, the "reactivation" transition from standby back to normal:
Transition Mode 2 -> Mode 1 can be done by pressing e.g. the shutter button


Current ML functionality:
Currently GPS Power Safe can be switched ON or OFF. If "on" then the GPS works like this:

Transition Mode 1 -> Mode 2 is timer based, GPS is switched OFF
Transition Mode 2 -> Mode 3 is done by the power switch, GPS is switched OFF
Transition Mode 1 -> Mode 3 is also done by the power switch, GPS is switched OFF

BUT when switching from standby back to normal:
Transition Mode 2 -> Mode 1 can be done by pressing e.g. the shutter button, GPS is turned back on but needs some time (~30-60s) to find the satellites. Until the satellites are found, no GPS data is written to the image files. This means that after waking up the camera you have to wait 30-60s to be able to shoot geotagged images - this is a no-go!


Solution:

Adding a new GPS Power Safe mode which works like this:

Transition Mode 1 -> Mode 2 is timer based, GPS still remains ON
Transition Mode 2 -> Mode 3 is done by the power switch, GPS is switched OFF
Transition Mode 1 -> Mode 3 is also done by the power switch, GPS is switched OFF

This way switching from standby back to normal will be no problem:
Transition Mode 2 -> Mode 1 can be done by pressing e.g. the shutter button, as the GPS is still active it does not need any initialization time to find the satellites. Therefore there is no delay when taking geotagged images. This is how it should work!


The Canon-Way
Switching the original Canon GPS functionality to "on" means:

Transition Mode 1 -> Mode 2 is timer based, GPS remains ON
Transition Mode 2 -> Mode 3 is done by the power switch, GPS remains ON
Transition Mode 1 -> Mode 3 is also done by the power switch, GPS remains ON

Therefore it is no solution to use the Canon way because GPS remains on during the transitions 2->3 and 1->3 and therefore depleting the battery even if the camera is switched off by the power switch.


Remark:
Normally you should switch the camer off by using the power switch. Then also the GPS functionality should be off. But during a shoot, or e.g. if you are on a city trip, you might want to use the power off timer to safe some battery power, but at the same time be able to quickly get back to active mode to take a picture. In this situation GPS should (as mentioned above) not be switched off.


Best regards,
Chris

[a1ex]

Thanks for the detailed explanation.

This feature needs a small bit of reverse engineering. Fortunately, it only involves figuring out what GUI events are sent at each type of shutdown, so I think it fits perfectly as an easy coding task (that is, any 6D owner with basic C skills should be able to do it^*).

^*) if (s)he is not afraid of using LED blinks for debugging, and has the patience to wait for 1 minute for every test run

http://www.magiclantern.fm/forum/index.php?topic=12650

[chris88]

Hi a1ex,
thank you for your answer. I hope that there will be someone who has the skills to try this. I would do it myself, but unfortunately I don't have any clue of C, not any clue of Linux, no clue of compiling. Also I do not have a second camera, so I have no possibility to use LED blinks for debugging. The last point is the biggest show stopper for me, because I can not afford to disable my camera. And as I am totally inexperienced, I am sure this would happen. So I hope there will be someone who is able to support with this. But as I have seen that the same question was raised by ptygmit in 2014 ( http://www.magiclantern.fm/forum/index.php?topic=3904.msg109369#msg109369 ) I do not have much confidence that there will be a solution in the next time.

Chris