Time Lapse and Flicker

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Table Rock Fire Click on Link to see the Time Lapse Video

So some of you have seen my Time Lapse videos. My friend Gabby Salazar had some questions about Flicker and how to reduce it, so I thought I would share this info with you. Tomorrow I will put up a Setup checklist for shooting time-lapse.

Flicker in Time lapse is always caused by exposure differences from frame to frame. Below I will discuss the causes of exposure differences and how to possibly decrease or eliminate them..

  • Aperture – Because modern cameras allow the aperture to return to widen open after the shot, the converse is also true. It must close down to the specified opening during the shot. So if your shot is at f16 and you are shooting with a f4 lens, the aperture closes down to f16 an instant before the shutter opens and then returns to wide open as soon as the shutter closes.

Why is this understanding important? Because the exactness of closing down to f16 is not precise. If your exposure is ¼ -1/10 of a stop different, you will never notice in side by side comparison. But run those images as frames in a video, and the exposure difference will be apparent as flicker.

How do you deal with this?

  1. Shoot wide open.
  2. Set your aperture and then disengage the lens slightly from body (this only works if your lens has a manual aperture ring). And it only works on some camera bodies.
  3. Use a GoPro.. Aperture is set, so you won’t have to worry about it.. But GoPros don’t focus well closer than about 16 inches.. Just remember that..
  • Automatic ISO– This can cause some flicker, more from the noise it might generate.
  • Automatic WB – The WB can change slightly during a shoot. Set your camera on 5000K WB.
  • Shutter Speed– This is where you want to pay attention to using a ND filter to lower the shutter speed. Shutters are not precise (maybe a tolerance of +/- 1/10,000 sec). If you are shooting at 1 second, the difference is imperceptible. Shoot at 1/4000 second and it can mean exposure difference of +/- 40%.. That is why you shoot at longer exposures. Or at least one of the reasons.
  • Changing Light– This is the bane of Time Lapse and impossible to control. If you set you camera on Manual, and have passing clouds, etc, you exposure will vary greatly. This is one time to set your camera to Aperture Priority, shoot wide open and hope for the best.

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