Using nd filter for a day to nighttimelapse

I'm pretty sure there's no way to do that without noticing it in post. My guess is the best way to do this would be to shoot on aperture priority and then shoot with a BULB shutter. Could be wrong, but this should work

any other thoughts?

Only thing I can think of would be to rig up some kind of motor to a variable ND... No idea how you would be able to do that precisely enough to match the actual exposure adjustment though.

Pretty sure the actual way to do that is to use a nice intervalometer that has bulb ramping.

Two or three years ago I did a night to day timelapse with no filters or anything, pretty much just used ML in manual mode, changed the exposure settings manually as the day brightened, turning the intervalometer on and off between exposure changes then turning it back. Somewhere like 20 or 30 second intervals between pictures so it gave me plenty of time to change settings, even had to change the battery once or twice. If that doesn't make sense I can probably explain it better, here was the outcome:

https://www.instagram.com/p/dSuAXou4_U/?taken-by=gavinrudy

Oh also forgot to mention I used a program called LRTimelapse which allowed me to smoothen and eliminate the exposure jumps present from when I changed the settings on the camera to compensate for a brightening day.

gavinrudyOh also forgot to mention I used a program called LRTimelapse which allowed me to smoothen and eliminate the exposure jumps present from when I changed the settings on the camera to compensate for a brightening day.

That one is dope man! I have LRtimelapse, so I guess I'm just going to use bulb ramping on magic lantern without the nd filter and see how that goes.