Technical question: is it possible to do low-light time-lapse filming that produces realistic "motion blur"?
At the beginning, there are a lot of shots where lights occupy long lines, as the earth turned during the exposure. Then jump to next frame, and the line has abruptly jumped forwards. Which is what must happen with sequential frames in low-light. So the total effect looks jerky.
Now let's suppose these were 30-second exposures. What if the camera instead took 30 1-second exposures, each of which were severely underexposed. But then software would add frames 1-30 to generate a well-exposed "final frame 1", then frames 2-31 to generate "final frame 2", frames 3-32 to generate "final frame 3", and so on. Each final frame would have full exposure, but the final output would be beautifully smooth, with "natural"-feeling motion blur.
This probably requires on-the-fly computation far beyond any kind of consumer camera. But does anyone know of software that does this? It would be fairly straightforward to write.
Yes that's possible. It would not be able to capture as much detail but you would get surpisingly far. The technique is called stacking in astrophotography. There is special software for it. Searching on astrophotography+software will get you some ideas of what is available. Stacking has revolutionized astro imaging and decent amateur pictures with moderate equipment + stacking can outdo professional work from a few decades ago.
Technical question: is it possible to do low-light time-lapse filming that produces realistic "motion blur"?
At the beginning, there are a lot of shots where lights occupy long lines, as the earth turned during the exposure. Then jump to next frame, and the line has abruptly jumped forwards. Which is what must happen with sequential frames in low-light. So the total effect looks jerky.
Now let's suppose these were 30-second exposures. What if the camera instead took 30 1-second exposures, each of which were severely underexposed. But then software would add frames 1-30 to generate a well-exposed "final frame 1", then frames 2-31 to generate "final frame 2", frames 3-32 to generate "final frame 3", and so on. Each final frame would have full exposure, but the final output would be beautifully smooth, with "natural"-feeling motion blur.
This probably requires on-the-fly computation far beyond any kind of consumer camera. But does anyone know of software that does this? It would be fairly straightforward to write.