A technique of time-lapse involves taking a picture at a regular time interval in order to create an accelerated film. Sounds easy, right? We have rounded up our thoughts and experiences on how you can enrich your own time lapses with the right equipment and techniques at your disposal.
Time-lapse as we know it is used to produce a video that emphasises the acceleration of time, and show something that the naked eye would simply not be able to see. The first question for this is what’s the point?
Uses of Time-lapse
- A time-lapse is used to show off something that is impossible to observe at real speed. A classic example is that of cloud formation as seen below. In real-time, you will not see their evolution because of their slow movement but with time-lapse the long-term movement is perfectly demonstrated.
- Time-lapse is also used to speed up an action that would have been impossible to film in real-time. As seen below, a 3D printing would take several hours in real-time but just a few seconds with use of time-lapse. Another example is the construction of a building over a year, and at a rate of one image per day the growth will be perfectly demonstrated.
- Time-lapses can be used to create rhythm breaks within a production. We created this within the AG-CX350 camera video to demonstrate real speed, slow motion, real slow-mo and time-lapses:
- Time lapse can be used to create a style within a production. The well known one is the “car headlamp trails” that we see in urban scenes, which is again not visible to the naked eye.
Calculating Time Lapse
Before putting time-lapse into practice, it is necessary to do a several calculations beforehand because it is important to predict the duration of the final result. The first parameter to take into account is the frame rate of the final edit (see our article on frame rates). Most commonly, it can be 24/25 or 50 frames per second (fps). It will therefore be necessary to take 24/25/50 photos in order to produce only 1 second of film.
The second parameter is the famous interval between each shot. Do I take an image every 2 seconds? Or every minute? To help make this choice, everything will depend on the scene and the movement of the objects it shows. Some rules that we have identified is as follows:
A very mobile subject i.e. a vehicle: interval of 1 to 2 seconds
A slower subject i.e. pedestrians: interval of 2 to 3 seconds
An even slower subject i.e the course of the sun etc: interval from 5 seconds to several minutes.
Of course, all this is only indicative, but the idea is there. So, to get our sequence and reason mathematically, for a 10-second shot, which will be broadcast at a rate of 25 frames per second (fps), and an interval of 3 seconds, we would apply the following formula to know the number of photos to take:
(Duration of the shot in seconds) X (final frame rate)
= Number (N) of pictures to be taken
If you don’t have a camera or a hybrid that includes the ‘Interval Rec’ or ‘Time-Lapse’ function (as found on most Panasonic cameras), you will need to apply the following formula to calculate the length of time to wait before the time-lapse finishes:
(Number of pictures to be taken) X selected interval
= Shooting time in seconds
In our example, we will have to take 250 images (10 seconds x 25 fps) and wait 250 x 3 seconds (interval duration). Either 750 seconds or 750: 60 = 12 minutes 30. That’s it, for the basic calculation. Obviously, it can be done the other way around i.e. “I know that the sun’s path before sunset takes 3 hours and I will set an interval of 10 seconds”. I will therefore need: (3600 seconds/1 hour x 3 hours)/10 = 1080 images. The shot will therefore last: 1080/25 (frame rate) = about 43 seconds.
Equipment for Time-Lapse
The hardware is fairly simple – a DSLR, a hybrid of a camera that can take a picture every X seconds. Even if you don’t have a camera with this functionality, you can purchase an “intervalometer” to connect to the remote socket of the device for it to be able to do so. It is the intervalometer that will decide whether to take a picture every x seconds. In Panasonic cameras, the function has been integrated for a long time and above all, the devices know how to assemble the images to make an internal film without having to edit them, meaning that you would get the video directly.
For the rest, a time-lapse is above all a shot that shouldn’t move (except in the case of a motion time-lapse). In order to avoid any image shake, you will need the following:
– A strong tripod (or any truly stable support). Even the wind can make a shot shake and ruin your shot if the support is not stable, especially with heavy optics in long focal length.
– A “power bank” (see our article on accessories) if you expect the shooting to take several hours. It will allow you to power your device for as long as necessary.
– A variable ND filter (or a set of ND filters). As we will see later, to obtain drag effects, we have to choose a very low exposure time (even several seconds). And so, even at night, it may be necessary to use a Neutral Filter to lower the amount of light and keep the shutter speed very slow.
The choice of interval and shutter
Now that we’ve gone through the necessary calculations and hardware needed to complete a time-lapse, we now have some time for reflection. Firstly, framing is extremely important. You also need to prioritise the moving or still subjects within your scene, and it is here where the choice of interval will play a role.
For example, you plan to shoot the unloading of a huge container from a boat onto a dock. The unloading will take an hour in total, and within the scene you will have the crane carrying the container and dozens of workers and vehicles on hand:
- If you opt for a very large interval (i.e. around 15 seconds), your final plan will highlight the path of the container (because the movement is very, very slow) to the detriment of the workers/vehicles that will flicker, appear and disappear. In 15 seconds, they will have covered a long way.
timelapse – discharging a container ship from Andre Freyboth on Vimeo.
- If you opt for a shorter interval (i.e. 1-2 seconds), they are the ones who will be highlighted, unlike the container which will seem almost motionless.
Everything is therefore a matter of both choice and priority within the composition. In terms of aesthetics, the shutter speed becomes extremely important, as it is that which determines the motion-blur. To take another example:
- With a fast shutter (1/50th of a second for example) you will increase the feeling of passage, because passers-by will be almost clear and seem to run and run again in this street.
- On the contrary, with a very slow shutter (1 second), they will all fade away and leave only diffuse streaks. In this case, you will prefer the street and buildings.
GH1 Timelapse test with intervalometer from Arthur Kulcsar on Vimeo.
In Practice: Manual Modes
With a time-lapse being a collection of photos, any gap between the two images will show. As a result, you have to remove all the automatic settings on your camera. To understand this, imagine that you are on the street completing a time-lapse with Autofocus. Each new photo will be focused on a different pedestrian, therefore if you use an automatism (opening of iris, shutter, ISO etc.), then this change will vary the parameters and adapt its settings.
In the end, you will not be able to exploit the result. The only downside might be the white balance, which can sometimes be left automatically. We recommend the following:
- Switch the camera to 100% manual: focus, aperture, shutter, ISO (Gain). We then set the device to Live-View/Constant Preview to see the impact of the settings. In the case of a camera, it’s useless as it does it all by itself. In the case of a DSLR, we recommend to also use manual lenses, as raising the mirror often causes the exposure to shift by a few milliseconds, which will be visible at the end.
- Once we have chosen the frame and locked the tripod, we take a test photo to fully check the quality of the photo and detect defects. In the case of a camera, we start a recording of only a few images to check the same settings. We adjust the parameters if necessary.
- We prepare the recording of the time-lapse (interval, shutter…) and start it.
Time-Lapse in Post Production
Once your time-lapse is completed, you have two options. Either your camera has already generated the film (in the case of GH4/5S, CX350 etc…) in the desired resolution, or you have saved the X images as photos on your memory card. In the latter case:
- Import all photos to a folder on your workstation
- In your editing software, import the images as “image sequence”. It will be played back as a movie one frame at a time. Or, if your software does not support this feature, specify that each photo should only last one frame when importing by dragging them onto your time-line
- For more advanced use, you can purchase specialised software such as LrTimelapse in conjunction with Adobe Lightroom. This type of application reserved for professionals will allow you to assemble the time-lapse, correct all inconsistencies from one image to another and even play on the RAW format of the photos if your camera is able to do so.
Techniques for Time-Lapse
To conclude, we will briefly discuss different techniques derived from time-lapse:
1. The ‘Holy Grail Effect’ for sunrises and sunsets
This technique consists of shooting a time-lapse from night to day and vice versa. As we remain in Manuel, the exposure will change from dark to full sun. So how do we do it? The easiest way is to split the time-lapse into 4 sections. In the case of a sunset, you start the shot slightly overexposed and as soon as you start to be underexposed, you pause and readjust the exposure. You then restart the second time-lapse. And so on until the dark night. During assembly, you will overlap the four time-lapses with a simple fade.
2. The Tilt-Shift
This effect consists in taking time-lapse from a very high point of view. With this technique the humans at the very bottom will look like little toy-like characters. We also add blur at the top of the scene and saturate the colours. The best way is to see this example in pictures:
3. Motion Time-Lapse and Hyperlapse
The motion time-lapse will require a slider and a motorised head that will move from position A to position B in the time interval. If you have to take 250 pictures, the slider software (which also controls the camera in general) will cut its movement into 250 positions and will only move between each picture. Hyperlapse is the technique of moving between each image while keeping a stable frame. It’s pretty hard to master, but the new sports or 360° cameras are starting to natively embrace this feature. This technique was also used extensively in Planet Earth II with the now infamous lizard sequence!