How to time-lapse Part II
- Category: Blog Filming and Video
- Published: Friday, 27 June 2014 09:53
What are time-lapses?
Practical thoughts on the time-lapse technique - Part II
How do time-lapse come into being?
The best way to capture the dance of the aurora borealis is by time-lapse: here in Norway.
An easy way to obtain a time-lapse is to simply let my video camera record a scene over a long period of time. The memory cards are affordable compared to the previous used tapes or even film rolls and the digital edit techniques make the cutting of the video material an easy-going issue. The recorded scenes are compressed in the software and played back at a higher speed rate (at two-times, three-times or eight-times the original speed). During this process single images are dropped following a certain algorithm. This is method an option if for certain reasons I want to use my main video camera, which does not feature an interval recording (note: for a long time I used a Sony video cam).
The method of taking a time-lapse by a film camera: just let it run over a long period of time. Picture taken on Bali, Indonesia
Yet as it eats up the memory on my cards I prefer to use my backup camera if the light conditions are not too problematic. This consumer camera (a Panasonic HDC-TM700) allows me to record at certain preset intervals but only in manual modus. And that for a very good reason: the automatic modus of the camera may change the focus or the white balance during the recording over longer periods of time. This is something to be strictly avoided so when “time-lapsing” it is best to use only manual settings whenever possible. By this method I can quickly insert the clip directly into the timeline of my editing program. And I avoid the so-called flickering, that is a problem, which I explain when describing the third method. A video camera opens seamlessly the aperture so that there are not even small exposure differences between two following images.
These two methods save you a lot of time and headache.
One oft he advantages of a small back-up camera for time-lapses: it is light! Perfect when I have to climb the steep volcano oft he Anak Krakatau in Indonesia.
Still the big disadvantage is their lack of flexibility: before starting the time-lapse you have to think thoroughly about the settings because you cannot change too much the contrast, white balance and so on in the post-production. Last but not least, unless you own a super expensive 4K video camera the time-lapse will be limited to HD resolution which doesn’t allow you too much of good-looking Ken Burn effects in the post.
The third way to record time-lapses offers the most possibilities but requires also the most concentration, accuracy and practice. You can take a series of still pictures at certain intervals with a photo camera and edit them later to a video. For this an IPhone would be already sufficient but the majority of the time-lapse aficionados use a DSLR camera for best results. The high light sensitivity achieved by good lenses and large sensors allows you to take images in light conditions where even a high-end video camera reaches its limits. For example, the “Holy Grail” of the time-lapse technique, that is the transition from day to night (or vice versa) requires altering the set-ups (the shutter speed and ISO) during the take. This is possible with a DSLR camera but not with a video camera. Additionally the possible lossless compression of the raw images gives you a lot of flexibility in the post-production as to brightness, white balance, contrast etc. The difference in resolution between the 5K (or more) images and the final HD video gives you a lot of room for playing with Ken Burns, panning or tilting effects.
Waiting for the night to fall on the top of a rock in the Chapada Diamantina NP/ Brazil
Yet there are also certain disadvantages that go along with this method. As a filmmaker I am acquainted with the photographic notions of framing a scene, proper exposure, focus and so on. Yet when I started to use this method I had to learn first the specific photographic capture techniques and the way a DSLR works. For example I had to take into consideration the buffer time a DSLR needs to store a raw image on the card. If the capture interval is shorter than the camera needs to empty its cache memory than it may happen that some images are not stored, producing thus ugly gaps in my time-lapse. This again makes a time-lapse with a DSLR more time-intensive because I cannot chose intervals under one or two seconds. Plus I need a lot of storage. Three to four sequences of raw night shots, which run over four hours, may easily fill a 64 GB CF card. The editing and storage of the processed images also cries for fast hard drives in the realm of terabytes. I cannot just insert the clip into the timeline and voilà there I have my time-lapse. With this method I definitely need more time to prepare the images of the sequence, not to forget the time I needed to learn the software for editing raw images. And what is the most annoying: if I grab a time-lapse with my video camera I can check the outcome on my display immediately afterwards. Time lapsing with a DSLR is like buying a pig in a poke, especially when I travel far to get my shots. Only back home I can tell for sure if the sequences were a success or a failure. (Due to weight issues I don’t carry a notebook. Besides I don’t have time to edit the sequences on my travels.)
I brought several northern lights sequences back home from my trip to Lapland (in northern Norway) last year. When looking through them I found out that one with a great aurora borealis was completely messed up. During a shift in the camera position the focus displaced from its original position. My mistake was that I didn’t thoroughly check the focus again. On the small display at night it was very hard to immediately recognize that the motive was out of focus.