Besides photography, I also do some indie film making in digital video, most of the time as director of photography.
I had to resort to use my K10D to make some time-lapse movies a few times, since not many video cameras are time-lapse capable.
After the usual trial and error, I've come up to some conclusions. So here are my recommendations:
1)
NO AUTO-FOCUS! You don't want your AF hunting and ruining 10 seconds out of a 30 seconds time-lapse clip. Just switch to MF and focus on the proper subject or near infinity or, even better, select an aperture for a good hyperfocal DOF.
Again, NO AUTO-FOCUS.
2)
Use a ND filter when shooting in daylight. I suggest at least a ND 8X (0.9) filter. This will allow you to achieve slower shutter speeds, which will give the clip a much smoother appearance. If the shutter speed is 1/15th of a second or faster, "blimps" might appear and can become intrusive at times. "Blimps" are moving subjects that seem to blink from one place to another.
If do you want "blimps", choose a faster shutter speed, like 1/60th of a second or faster.
3)
When shooting over a long period with some big differences in lighting conditions (like from afternoon to night), mount a low contrast filter on your lens as well. This kind of filter is used in the video industry to mimic the results of film, since digital video is often too contrasty. This filter helps achieve the smoother tonal variations we're used too see in film.
Using such a filter will reduce contrast and lift up details in shadows, so you can under-expose a bit to decrease the risk of highlight clipping (to some extend). In some circumstances, it will give you about a stop of additional dynamic range in the shadows.
4)
When possible, use the AE-lock to prevent the sometimes less accurate exposure metering of the evaluative metering system, which will result in inconsistent lighting of the time-lapse sequence. IMO, the Pentax evaluative metering isn't very reliable for such use and can sometimes go "berserk", overexposing or under-exposing a few shots here and there. (There isn't any DSLR with a metering system suited for such use, IMO.)
Better, expose using spot metering (and whatever exposure compensation that is needed) on a part of the frame that can provide consistent results for the whole frame and the whole duration of the clip.
An example? If you shoot a high-rise building under the autumn sky from dawn to noon, metering on the concrete wall will result in a building lit with much more consistency than if you're metering the sky or the windows. That's if you want the building to be properly lit, of course.
5)
In any exposure mode but M (manual), I suggest you use an average ISO (400 is often best) setting for extended shootings, especially those going from day to night or night to day. You'll see less difference in shutter speed variation (in Av mode) or field of depth changes (in Tv mode).
If shooting on shorter periods, with less important changes in lighting conditions, I suggest you select the lowest ISO, so you can achieve longer shutter speeds and reduce the risks for "blimps" to appear.
6)
Use either M (manual), Av (aperture value) or Tv (time value) exposure mode.
M mode means your aperture and shutter speed remains constant. However, since most DSLRs can only handle about 8-9 stops of dynamic range (about 9-10 with the low contrast filter mentioned above), extended time-lapse photo can become less interesting, because the initial exposure, which could have been good at noon, just might have gone completely wrong at sunset. Going from a sunny noon to past sunset in summer often means going throught 12 stops of dynamic range.
Av mode means constant aperture and depth-of-field, but higher risks of seeing "blimps" appear. It does however prevents overexposure most of the time (the shutter might go up to 1/250th of a second to prevent that) and is well suited for extended time-lapse photography.
Tv mode means constant shutter speed, so no "blimps" there. However, depth-of-field might change during the time-lapse clip. This can be troublesome if your subject is close to the camera, but shouldn't be a problem if you focus on or near the infinity. The other risk is to get some overexposure (since the aperture can only go down to F/22, F/32 or F/45), especially if you choose a long shutter speed (like, say, 1/4th of a second).
7)
Last but not least, cloudy days are just the best for shooting time-lapse clips, since the constrast is lower and the exposure variations are much smoother. (Especially if the sky is clearing at night to reveal the stars — then: bingo!)
And I would never recommend shooting around noon in summer unless you have a very strong ND filter, since even at F/22 you'll often experience blimps or get some overexposure (or clipping), or get... both problems!
Winter, with its shorter days and weaker sunlight, is much better for shooting time-lapse clips at noon (and for time-lapse photo in general).
Hope it helps.
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Once you've mastered the technique and the equipment, you can concentrate on
the more important aspects of photography: originality, atmosphere, emotion
and — ultimately — soul.
— Jeff
I like the way the clouds (well, the wind) change direction part way through, and the way they roil and stuff, and the way the sun blinks in and out.
