Time Lapse - FPS Override and Shutter Speed

[CTYankee]

I've been using my 5D and 5D mkII for time lapse, but want to use ML on the mkII to save the shutter a bit...already at 360,000k

I've been playing with the FPS Override feature and not sure I understand it. If I wanted to have a time lapse with the following settings:

One shot every 3 seconds.
Shutter speed 1/30
Aperture (adjusted to get correct exposure).

I've been using the "Low Jello, 180d" setting for optimizing. Then adjust the Shutter Range to include my desired shutter speed.

However if I get down to the very low frame rates (for very slow time lapse) the shutter speeds become very difficult to adjust. I can play around with the time B value to get a shorter shutter speed, but I don't really understand what I'm doing. I see two numbers: xxxx (FT+/- xxxx). What do those mean?

Lastly, is it possible to use ML FPS Override to shoot star time lapses? Those require a shutter speed of ~30s and one shot every minute or so. I can only get a 5s shutter speed. I'm sure there are limits to ML TL and using the shutter to take 'real' photos is a better way to get night shots (noise reduction and higher res images).

thanks for the help, and of course for this amazing firmware!

[dexMilano]

Following

[halbmoki]

FPS override is somewhat limited. It's just not possible to go under 0,2FPS. For star timelapse and similar effects, there's no other way than stressing the shutter some more. Of course you could raise the ISO (also with ML digital gain) until speeds of about 5sec are enough, but I guess you don't want that much noise. For lower FPS you can use silent picture and intervalometer, but that doesn't change anything about the shutter speed and the resolution is even lower than full HD video. It's better to record low-FPS video and speed it up some more in post-processing.

Getting the desired shutter speed in video mode is done with "exposure override" from the expo menu and then setting the shutter speed from there. It gives you full manual exposure, so you need to carefully check the histograms for a proper exposure. At least that's how it's done with my 50D, so I guess it's the same for a 5D.

As for the timers in FPS override... only the devs know how that works. I have no idea and usually just select the setting that's closest to what I need for the current situation.

[a1ex]

http://wiki.magiclantern.fm/userguide#fps_override

FPS override is limited, but you can use a ND filter in daylight. For stars it's not so good, maybe it can be better with a f1.4 lens.

I've tried to record some stars with FPS override on 5D3 (samyang 8mm f3.5):

Compare it with a timelapse from still pictures (with intervalometer):

[tinyenormous]

Congrats on hitting 360,000! I think you may already be living on borrowed time

I think for the res alone, shooting stills is a must-have. Have you ever considered getting a cheaper body just for TL? I've thought about this a lot as well. I bought a t2i to save wear on my 7D (and so I could use ML) but I don't know if I would do the same again. Actually, it looks like replacing the shutter on your 5D classic is $200-$400 so that would be the cheapest option, and you wouldn't have to do anythign until it actually fails! Some people are reporting several _million_ actuations with no failures.. Low frame rate video is fun to play with, but it doesn't give you anywhere near the latitude as a sequence of properly exposed raw files, or HDR pairs.

The "180d" part of the preset means that it is trying to stay open for half of the interval time. Since 0.2 fps is the slowest that ML can go, that means that 10 sec is the longest interval that makes sense(5 sec exposure, 5 sec wait). I have no idea what ML tries to do once you change the timers, but it seems like the best it could do is to move towards a 360 degree shutter. Even that would end up with a 10 sec exposure every 10 seconds.

Lastly, with a 30 second exposure and a 60 second interval you would shoot 12*60=720 stills if you did a 12 hour day to night to day sequence. That's 0.225% of the median shutter life from here http://www.olegkikin.com/shutterlife/canon_eos5d.htm

In short, I wouldn't sweat it. Save the FPS for the daytime if you want to save clicks. Use 'em up at night!