Time lapse video

Use a time lapse as a great way to condense a long process into a more focused and interesting visual but there are challenges to overcome in making it work well.

Any video needs to have a clear subject to hold the viewer's interest or it risks the purpose of the video being lost in the general background, and failing to achieve the intended purpose.

Timelapse - roofing on new building construction

Just putting a camera in position and leaving it to work without managing the shoot process can mean you miss a lot of the action. These cameras quite often use wide angle lenses which make it difficult to distinguish the intended subject from the overall action.

“A time lapse should catch the important parts of the subject while condensing the background into a recognisable shot.”

So setting up a time lapse needs planning and management. Some key factors are;

- What is the subject and how does it fit into the overall video. A relatively small subject in a wide angle shot risks being swamped, whereas a tight angle on a small subject risks loosing the overall context of the scene.

- What are the restrictions on the placement of the cameras. Locating a camera for an extended period of time needs to take into account the site requirements, the planned evolution of it, so that it is able to capture the information required for the period needed.

- Will the location evolve over time, for example will walls or other structures go up that impede a camera field of view. Whats starts out as the ideal camera location may not be the case later in the shoot.

- When is the action that is wanted to be captured take place and what will the conditions be like when it does. Issues like the position of the sun relative to the subject and the camera need to be taken into account or run the risk of the product being unusable.

Then there are the physical problems of getting the right content to create the final video. These are complicated by the duration of the time lapse. Something taking a day or less is easy to manage, whereas something that may be several months or longer in duration, such as a building construction, will need a lot more management. This also affects the technique used to make the shots; where possible opting for the largest file format means that you have greater flexibility in post processing but at the expense of a higher time cost for this editing.

Access to the camera when needed, power supply, a means of retrieving the data, these all depend on the location arrangement and the duration of the shoot.

Selecting the camera set up depends on the subject and the intended use of the time lapse. The main points are to select the frame rate that will create the intended visual effect, and the speed of the shutter in camera to create the required image qualities. The camera will need to be able to provide the quality of image required by the design of the shoot.

Where the subject is busy, there is a lot going on, a fast frame rate - perhaps one frame every second - will make for capturing a continuous flow of the action. If the subject is more gradual a slower frame rate will be used, perhaps one every five seconds or in some cases a lot longer, minutes or tens of minutes. The usual criteria is to calculate the frame rate that will provide a smooth flow for the end product; you can always shoot more frames than you need and not use them, but there is no recovery from not having enough frames to work with.

The shutter speed will dictate how motion in the time lapse will be presented. It may be that people are not to be seen clearly, in which case a frame rate of 1/10th of a second will make for a blur of anyone moving. If each video is to have a full crisp and sharp content then a frame rate adequate to capture that will be needed; people walking at least 1/125th of a second.

Time lapse can also be used to condense very long periods of time. An extreme example would be a plant growing which can take months perhaps. Here the criteria may require the camera to be located at precise co-ordinates so as to always work from the same position, with adjustments being made in focus at every stage of the shoot. These sorts of shoots tend to take place under very controlled conditions as the investment in achieving a good result is significant.