The Basics of Time Lapse Photography
We live in an exciting time for photography. It’s more accessible than ever before and even entry-level cameras are capable of capturing high resolution images at great quality.
We also live in a time where the lines between still and motion pictures are blurring. Inexpensive high quality video capture is a reality and with increased bandwidth and better compression, the demand for video content is increasing at a phenomenal pace.
One area of this convergence of still and video that’s of particular interest to still photographers is time lapse photography. This technique truly allows you to see the world in a totally different way and requires little in the way of additional equipment.
What is it?
Time lapse photography is the art of compressing a long period of time into a shorter one during playback. How long a period you shoot over and how long you take to play it back are entirely up to you. Basically you set the camera up to take images one after the other, waiting a specified interval between each one.
When done correctly, the results look like this:
As you can see, it brings the scene to life in a way that a still photography can’t.
What Equipment do I Need?
Obviously you need a camera – and I recommend a digital SLR. Doesn’t need to be anything fancy, an entry-level model is just as capable as a top-end one as far as this process goes.
After that, you need a tripod. And it has to be a good one that is very stable – any camera movement at all during the time lapse will be very visible. A cheap tripod might be OK on a completely calm day, but if there’s any wind you need something that won’t vibrate or shift. For advice on choosing a tripod, you can see my article on the subject.
Lastly, you need an intervalometer – this is the only piece of gear that you likely don’t have already. The intervalometer is a programmable cable release that lets you instruct the camera to take one exposure every x seconds. Since I use Canon equipment, I use the Canon intervalometer, which they call the TC-80N3. Here’s what it looks like:
This is a critical item, as without it you’ll (a) be bored silly pressing the shutter every few seconds for an extended period of time and (b) you won’t be able to keep to an exact schedule so the time lapse will run at an uneven pace.
A rain cover and lens hood is a good idea if the weather is likely to turn and you’re not shooting from a sheltered location. Other than that, there’s not really anything else you need to get started.
What Camera Settings to Use?
For this article I’m going to talk about time lapses that don’t involve radical changes in scene brightness (i.e. not at dawn or dusk). With that in mind, camera settings are pretty straightforward.
You shoot in manual – you need each exposure to be the same as the last, or else you’ll get flicker when playing back the movie. Your shutter speed should be relatively slow, so that any moving objects in the time lapse are slightly blurred. If not, the final playback may appear jittery. A good rule of thumb is to have your shutter speed be half your interval time. So if you’re shooting a four second interval, your shutter speed should be around two seconds, if possible.
Doing this in the middle of the day would require using the smallest available aperture and the lowest ISO. If that’s not enough, then a neutral density filter may be used to cut down the intensity of light reaching the sensor, allowing a longer exposure.
If you don’t have any ND filters, then don’t fret – just slow the shutter down as much as possible without compromising the exposure and you should be fine.
You’ll also want to set your white balance manually (or shoot in RAW and normalize the white balance across all the images in postproduction).
You’ll need to set your focus to manual as you don’t want the camera refocusing for every shot. Autofocus where desired for the first shot, then switch to manual and be careful not to move the focus ring by accident.
A Word on Choosing Exposure
It’s important to try and anticipate what is likely to happen to the available light during the time lapse. If it’s likely to get brighter, then you need to set your initial exposure to be a little darker than you might if taking a single image. If you don’t allow some headroom, and the Sun comes out from behind clouds for example, then the image will become overexposed and you’ll lose detail in the highlights. Likewise if it’s likely to get darker, set your initial exposure to be quite bright (without overexposing, of course).
Locking the Aperture
One thing that surprised me when I tried my first time lapse was that even though I used manual exposure settings, there was still a noticeable flicker in the playback. This, I discovered, is largely due to the aperture.
In modern cameras, the aperture is electronically controlled. That means it closes down to the desired setting just before exposure. Unfortunately, there is a slight margin of error, and it doesn’t end up the exact same size every time – there are tiny discrepancies. Not a problem for still photography, but a big one for time lapses.
The solution here is to either use an older lens with a mechanically controlled aperture, or to do something to lock the aperture in the lens you have. With Canon cameras, the way to do this is to set the desired aperture, press the depth-of-field preview button and while holding it down, unlock the lens and rotate it so the electrical contacts are no longer touching. Then, when you release the DoF preview button, the aperture stays at the set size and won’t move again until you relock the lens.
This is a bit of a nasty solution, and carries the risk that the lens could fall off the camera if you forget it’s not securely locked when you put it away. Consider yourself warned – do this at your own risk!
Picture Quality Settings
I’m a big advocate of shooting RAW, as it gives you significant advantages in postprocessing and image quality. However, with time lapse photography, the final resolution is much lower than normal for still imagery – full HD video is 1920×1080 pixels, which is just over two megapixels. You’re also shooting a LOT of images, so at full resolution you’ll fill up your memory cards pretty quickly.
The solution here is to shoot JPEG, and also at a lower resolution. Check out your camera’s documentation for specifics, but you need it to be at least 1920×1080. A bit more is desirable if you want to create any Ken Burns style pans or zooms in your final movie.
Another option – one that I use – is a lower resolution RAW format, if your camera supports it. Many cameras bought post-2009 have that facility. On my 5D Mk II, I can specify a five megapixel RAW file (significantly smaller files than the full 21mp!). This allows me to leave the white balance on auto and just correct it later in post. It also preserves as much quality as possible in the source images.
As you’ll be taking lots of images, battery power is going to be an issue. Make sure you have a fully charged battery with you, and an accessory battery grip for the camera is probably a good idea – that way you get to use two batteries at the same time, leading to longer shooting times. You don’t want to have to swap memory cards or batteries mid-shoot, as that will result in visible jumps in the final playback.
A useful accessory here is an external power source. Many cameras have accessories available that allow you to hook the camera up to a mains power supply. Obviously you’re not likely to have a power socket available out in the landscape, but you can get an inverter for your car that will let you run the camera off the car’s battery.
This option is likely not necessary unless you’re shooting several time lapses a day, or if you want to do one very long one (say, from dawn until dusk, or dusk until dawn).
At any rate, I make sure to switch off the automatic image review on my camera before starting a time lapse. You won’t be there to look at it, and the LCD screen takes power you’re going to need to make the images.
Setup for Mourne Time Lapse
How Many Images?
This is a crucial decision. You have three things to consider – how much real time do you want to pass, how long do you want the final movie to be, and how quickly do you want things to move in the final movie.
These are all closely related. If you want a full day to pass, but only want a thirty second movie, then everything will go quickly. Likewise, if you want a two minute movie, but only want to capture an hour of real time, then things will move quite slowly.
The thing to remember is that your movie will play back at about 25 frames per second (may be more or less depending on what’s standard in your part of the world). That means that 25 individual photographs give you one second of footage. So 1,500 frames will give you one minute of footage, or 750 frames for 30 seconds. That’s an awful lot of photographs.
Make sure you can get however many frames you need to take on one memory card – you don’t want to have to swap out halfway through.
A key concept is that (within a specific timeframe) the more frames you take, the slower the action will move. If I do a time lapse where I take a frame every 2 seconds for an hour, I get 1800 frames which equals 72 seconds of footage at 25fps. If I do the same time lapse, but this time take one frame every 4 seconds instead, I get just 900 frames which equals 36 seconds of footage.
In both examples, the same amount of real time has passed, but in the second one everything moves more quickly because it’s a shorter movie.
As you can see, there are many factors to consider. You need to decide what works best for the scene you have in mind, and what your intended use is. Is it going to be cut together with other footage into a larger composition or is it going to stand alone? Are you trying to convey speed, or something more relaxed? Etc..
Images Captured, Now What?
Now that you have your images on the memory card, you have to put them together into a movie. The simplest way to do this is to buy something like Quicktime Pro, which will accept a sequence of images and then compress it and save it out to something that can be put on the web.
I’ll have an article on the subject of movie creation in the months to come, but your basic steps to create a stand-alone clip are to create copies of your source images in whatever aspect ratio you want the final movie to be (16:9 is a good choice). Open up Quicktime Pro and select the ‘Open Image Sequence…’ option. Select the first image in your sequence and it will ask you for the desired frame rate. Select whatever’s appropriate (25fps in Europe, 29.97 or 30 in the US) and continue. It’ll churn away for a while, and then show you your movie.
If you want to save it out, you’ll need to export it. Choose the appropriate settings (if you choose ‘Export for Web’, it’ll give you helpful presets) and you’re good to upload it to your favourite video sharing site. Send me an email with your work, I’d love to see it.
I hope that you have found this tutorial useful. If you’d like to improve your camera or post-processing techniques, I run regular workshops at my studio in West Cork and in Dublin.