D800 4K Time Lapse in Hawaii (and some photos)

Started Dec 14, 2012 | Discussions thread
Reverb
Regular MemberPosts: 264
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Timelapse Shooting Technique
In reply to Reverb, Dec 15, 2012

Thanks everyone for the compliments.  I will reply to some of you individually but there seems to be interest in the technique and I'm happy to share so will post a few things in a few messages over the course of the next day or so.  Over the course of the past decade of photography I've gleaned a lot from the dpreview forums and I'm happy to contribute back.

The basic concept for timelapse is easy enough, you tell the camera to shoot a sequence of photos in a row from a stable platform (actually even the stable part is not necessary but that's a story for another day).   The key variable is the interval between shots. There is an art to selecting an appropriate interval but I think 3-5 seconds is a good baseline but it really depends on the nature of the scene, you get a sense of the right interval setting through practice.  To provide some guidelines though: The scene with the people diving in the water is about a 1 second interval while many of the cloud scenes are 3-4 second intervals.  You generally want to air on the side of shorter intervals because you can speed a timelapse up in postprocessing but can't slow them down without it looking bad.

You determine the number of shots you want to take by thinking about how long you want the scene in the movie and then multiplying that by the number of frames per second of the final movie.  So if you want a 10 second clip (probably the average clip length in my movie) and are shooting in a 24fps movie (I recommend this frame rate over 30fps as I think it looks more film-like as it matches the 24fps used in movies) then you need to take 240 shots.  The math can be frustrating when you want to figure out how long in total you need the camera to run  (i.e. number of shots x frames per second x interval) but there is a free iPhone app that I used, called Timelapse, that does the calculation for you.

So that's the basic process for doing a timelapse but getting a good quality clip is a challenge and it requires you to think quite differently about the technical process of taking a photo then you do for still photos.    As one of the posters above noted, you need to lock down as many photographic variables as possible so things don't change between shots (unless you want them to do).

Among the things you need to do prior to shooting a timelapse shoot:

  • Focus: you need to prefocus, then switch the camera to manual mode so that the focus doesn't change between shots;
  • White Balance: you need to switch white balance to manual white balance (or shoot in RAW and then impose a uniform white balance setting on all photos  which I recommend for postprocessing, but I'll save that for another post); and
  • Exposure: You generally need to use your Camera in M mode to pick a single shutter and aperture setting to be used throughout the shot.

In addition, the mechanical imperfections of all still cameras make it difficult to have a stable timelapse scene.  It turns out that there is some variation between shots simply because apertures and shutters are not completely precise and consistent shot to shot and this variability can ruin a scene for timelapse. This flicker between scenes is the bane of timelapse photographers.

So you need to shoot as wide open as possible and keep your shutter as slow as possible to minimize the variability between shots.  As a result, I highly recommend an ND filter so that you can bring the shutter speeds down to at least 1/10".  A lot of the shots in that video are done with a Lee 10-stop ND on the camera.  You generally want a fairly slow shutter speed anyway so there is some blurring in between shots, this looks much more natural in the final result (see the scene of the cars moving by the road). Even with all this effort, eliminating flicker between shots is difficult and I use a software program in postprocessing that helps.

You can also avoid issues with variable apertures by using a lens (I have two Zeiss lenses with manual aperture control) to do this but also possess a Canon to Nikon lens adapter that also sets a manual aperture for the Nikon lenses if I'm using them on a Canon.

Finally, I will acknowledge that despite all of the above there is even more advanced techniques needed for some type of scenes.  In particular, there are some scenes where light naturally varies in a significant way (particularly sunrise and sunset) and a camera left on M mode will end up grossly over/under exposing if left alone.  Some people solve this issue by turning turn their camera to aperture mode, letting the camera change the.  However this can introduce significant flicker (though it can be minimized via postprocessing) and isn't my preferred technique.

For scenes involving big changes in light (i.e. the opening and closing sunrise/sunset scenes in my timelapse movie) I used a technique called bulb ramping where the camera slowly increments (it has to be in bulb mode to do this) the exposure time for a photo to match changes in the light scene. Unfortunately, there is currently no way to do proper bulb ramping for Nikons, which is one of the reason why I brought my 450D on my vacation with me.

Instead, I tethered my 450D to a netbook and used a program called GBTimelapse (http://www.granitebaysoftware.com/Default.aspx) which measures the light level of a scene and figures.  It's quite advanced software and can use your location to determine how long sunrise lasts and you can also program how quickly it responds to light changes, etc.  GB timelapse is unfortunately only available for Canons due to Nikon's inability to do bulb ramping.

It's tough to do a good sunrise and sunset scene well and I'm not sure if I perfected it yet.  The ability to change between night and day is called the "holy grail" in timelapse photography for a good reason.

Anyway, those are some of the basic tips.  I'm happy to answer any questions.  Sometime today or tomorrow I will post some postprocessing info since postprocessing video timelapses is very different then still photos.

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Reverb www.alexdimson.com

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