I have been running a pretty long term timelapse on an EOS R that I have. It has been going for several months now, taking photos at 5min intervals. Here are a few things I've learned specific to such long term timelapses that might help other people doing long timelapses.
1) Don't rely on the camera's native timelapse feature for a few reasons.
I realized that when doing a really long timelapse, it's best to use an external intervalometer and join the photos into a timelapse after the fact with software. The internal feature is good for shorter timelapses, but there are some big drawbacks for long timelapses. First and most obvious, the number of frames is limited to 3600 in the camera. Second I have noticed that even though the camera has a feature where it can adjust exposure for each frame, I've realized that there seems to be a limit to how much the camera will adjust the exposure between each frame. It took me a while to realize this was causing my problems. If your frame rate is fairly quick, say every 45 seconds or so, this will not cause an issue with a transition from daytime to night if you are doing an outdoor scene. However, in my case, a frame rate of 1 frame every 5 minutes meant that the camera did not allow the exposure to adjust from daytime to nighttime smoothly. Obviously this isn't an issue when using an intervalometer since each and every frame will have the proper exposure adjustment. I'm not aware of any documentation that talks about this weird lag in timelapse mode to adjust the exposure from frame to frame, so it's worth noting.
Also, one set of fresh AAA batteries has been running my intervalometer timer for a few months now. I thought the intervalometer battery life might be an issue, but it hasn't been.
Using an intervalometer allows you to check settings and review photos between frames as well, which is nice for a very long term timelapse.
2) Turn off sensor cleaning completely.
Obviously I have been using the full electronic shutter so I don't put thousands of additional clicks on my camera, but one thing I learned is that you should probably turn off sensor cleaning as well. The only error I had when doing this timelapse was once when the camera suddenly popped up an error saying it could not complete sensor cleaning. I thought maybe the sensor cleaning mechanism was toast because it has been running every 5 minutes for months (each time the camera goes to sleep between frames) but actually it was just a one time fluke error. Once I powered the camera on and off, sensor cleaning started working again. But obviously the sensor cleaning routine is apparently a little bit of a weak spot for reliability since it errored out on me one time. I decided it's probably best just to disable sensor cleaning. Curiously, I discovered that you can't even set it to just clean the sensor at power off, because apparently the camera considers going to sleep as powering off, as it kept running the sensor cleaning when it went to sleep until I turned off the sensor cleaning completely.
3) Use a Canon genuine DR-E6 DC coupler to power the camera.
I learned this before, but third party knockoff DC couplers (dummy batteries) are recognized by the camera as a battery, not a true DC coupler, so eventually the camera will think it has depleted the "battery" and will shut off. The Canon genuine DR-E6 is recognized by the camera as a true hardwired power source, so the camera will run indefinitely on it as long as there is power. Do be aware though that you can run the DR-E6 from a third party AC to DC adapter, as long as it has the proper connector to plug into a DR-E6. And the DR-E6 uses a little bit of a weird connector, so not all third party AC adapters fit it.
1) Don't rely on the camera's native timelapse feature for a few reasons.
I realized that when doing a really long timelapse, it's best to use an external intervalometer and join the photos into a timelapse after the fact with software. The internal feature is good for shorter timelapses, but there are some big drawbacks for long timelapses. First and most obvious, the number of frames is limited to 3600 in the camera. Second I have noticed that even though the camera has a feature where it can adjust exposure for each frame, I've realized that there seems to be a limit to how much the camera will adjust the exposure between each frame. It took me a while to realize this was causing my problems. If your frame rate is fairly quick, say every 45 seconds or so, this will not cause an issue with a transition from daytime to night if you are doing an outdoor scene. However, in my case, a frame rate of 1 frame every 5 minutes meant that the camera did not allow the exposure to adjust from daytime to nighttime smoothly. Obviously this isn't an issue when using an intervalometer since each and every frame will have the proper exposure adjustment. I'm not aware of any documentation that talks about this weird lag in timelapse mode to adjust the exposure from frame to frame, so it's worth noting.
Also, one set of fresh AAA batteries has been running my intervalometer timer for a few months now. I thought the intervalometer battery life might be an issue, but it hasn't been.
Using an intervalometer allows you to check settings and review photos between frames as well, which is nice for a very long term timelapse.
2) Turn off sensor cleaning completely.
Obviously I have been using the full electronic shutter so I don't put thousands of additional clicks on my camera, but one thing I learned is that you should probably turn off sensor cleaning as well. The only error I had when doing this timelapse was once when the camera suddenly popped up an error saying it could not complete sensor cleaning. I thought maybe the sensor cleaning mechanism was toast because it has been running every 5 minutes for months (each time the camera goes to sleep between frames) but actually it was just a one time fluke error. Once I powered the camera on and off, sensor cleaning started working again. But obviously the sensor cleaning routine is apparently a little bit of a weak spot for reliability since it errored out on me one time. I decided it's probably best just to disable sensor cleaning. Curiously, I discovered that you can't even set it to just clean the sensor at power off, because apparently the camera considers going to sleep as powering off, as it kept running the sensor cleaning when it went to sleep until I turned off the sensor cleaning completely.
3) Use a Canon genuine DR-E6 DC coupler to power the camera.
I learned this before, but third party knockoff DC couplers (dummy batteries) are recognized by the camera as a battery, not a true DC coupler, so eventually the camera will think it has depleted the "battery" and will shut off. The Canon genuine DR-E6 is recognized by the camera as a true hardwired power source, so the camera will run indefinitely on it as long as there is power. Do be aware though that you can run the DR-E6 from a third party AC to DC adapter, as long as it has the proper connector to plug into a DR-E6. And the DR-E6 uses a little bit of a weird connector, so not all third party AC adapters fit it.
