In a previous tutorial I showed you how to use your smartphone and a TriggerTrap mobile dongle as an intervalometer to take time-lapses with your DSLR. In this tutorial, we dive deeper into one of the special kinds of time-lapses you can do with TriggerTrap and your smartphone: a bramping time-lapse.
Bramping is a portmanteau of bulb and ramping. It’s a time-lapse where the shutter speed, controlled by an intervalometer, gradually changes over the length of the shoot.
In situations where the light is gradually changing bramping is a great way to keep your exposures relatively constant. Sunrises and sunsets are the perfect opportunity to use this technique. If you don’t adjust your exposure throughout a time-lapse at sunset, for example, the frames will become more and more underexposed until they are completely underexposed and totally black. By gradually lengthening the shutter speed throughout, you get a far more gradual (and pleasing) transition from day into night.
Before continuing with this tutorial, please read my first one on time-lapse and long exposure control with the TriggerTrap mobile dongle. It covers all the basics of the TriggerTrap mobile dongle and TriggerTrap smartphone app (available for both iOS and Android), which I won’t be repeating here.
You will also need a TriggerTrap dongle, an iOS or Android device to control it, a tripod and your camera. The technique in this tutorial is more advanced than a simple time-lapse so you should have some familiarity with making basic time-lapses before trying bramping. The other posts in this series are enough to get you started.
Setting Up the Time-Lapse
Bramping is easier to do at sunset than sunrise: you can set up in daylight rather than in the dead of night. Get to the location around an hour before sunset. Depending on where you are and what time of year it is the speed at which light levels drop changes. If you’re not familiar with the local area, ask someone who is how fast the sun sets.
Lock your camera securely down on the tripod and frame your shot. This step’s important because you don’t want to waste two hours on a poorly composed time-lapse. The key thing is to think carefully about how the image is framed. Focus where you want in the scene and then switch your lens to manual focus.
For a time-lapse with a rapidly changing sky it’s usually best to leave your white balance on auto. The colour light will change dramatically as the sun sets.
Put your camera in manual mode and dial in your aperture and ISO settings. The fastest shutter speed TriggerTrap (and most cameras) can handle for bramping is 1/15 of a second. Some cameras might not be able to work at that speed, so check and test your equipment before you head out.
For time-lapses I like to use an aperture of f/16. For for bramping time-lapse an aperture that small won’t work as well because of the transition from light to dark. I find f/8 or f/10 to be the sweet spot where you still have depth-of-field throughout the scene, especially if you focus using your lens’s hyperfocal distance. At this setting you but don’t have to crank your ISO too high to compensate. These are also usually the sharpest f-stops in most lenses.
Set your shutter speed of 1/15 of a second or slower, and then select an ISO that produces clean images. For most DSLRs this will be around 400 or so. You don’t want to set your ISO too low; it is the key to well exposed images after the sun sets. If you want to start with a shutter speed slower than 1/15 or have a lower ISO you can use a neutral density filter. Be careful, this will affect the exposure time for the dark portions of the time-lapse too. Once you’ve found the settings that produce well exposed frames at 1/15 set the exposure to Bulb.
If there’s any breeze, hang a heavy bag off the hook that most tripods have on their centre column. This reduces unwanted vibrations that can degrade your images. Similarly, if it’s likely to rain either set your camera up under cover or shelter it with an umbrella, waterproof cover or plastic bag. Safety first!
Bramping With TriggerTrap
I’m using TriggerTrap on my iPhone but the process is the same on an Android device. Connect your phone to the TriggerTrap mobile dongle, and the dongle to your camera’s remote port.
For the Start shutter speed select 1/15, or slower if you are using neutral density filters. For the End value you’ll have to guess. There are no hard and fast rules on what will work. Any artificial lights will have a dramatic impact on the exposure, as will light from the moon and the stars. The more light there’ll be after sunset, the less you need to lower your shutter speed. I find a value of around 1 or 2 seconds to be fairly safe in most situations. So long as you shoot in RAW, you’ll still get useable files. If you’re able to take a test shot the night before in the same location to work out your final shutter speed, do.
Like with a regular time-lapse, calculate how long you want your final movie to be. For most time-lapses I use the cinematic standard of 24 frames per second. At that rae, for every second of the final video, you’ll need 24 shots. Enter this value in the Exposures section.
Finally, set the Interval between each shot. This determines the Duration of the shoot. You need to make sure to set an Interval that’s longer than your final shutter speed. If you want your time-lapse to cover a set time, you can calculate that by dividing how long you want it to be by the number of frames in your final movie. Otherwise, you can just tweak the value in TriggerTrap until you get a Duration that you’re happy with.
Once that’s done, push the big Red Button to start and settle in for the shoot. I always bring my Kindle with me to get a little reading done while I wait.
For this time-lapse I took 360 photos over the course of an hour. At 24 frames per second it’s a 14 second movie. The starting shutter speed was 1/15 of a second and the final one was 2 seconds. All the photos were taken at f/8 and ISO 400. I started shooting 20 minutes before sunset but had to restart ten minutes later after a seal destroyed my shot by drawing a crowd. Yes I had a photo shoot wrecked by a pesky seal.
Bramping is an great technique for shooting time-lapses during dynamic light. Many of the most popular time-lapse videos use bramping to go from shooting a sunset to exposing for the milky-way. There’s also a lot more that can be done with bramping using advanced tools and techniques, but the TriggerTrap mobile dongle is a great way to get started.
If you’ve tried taking a
time-lapse with the TriggerTrap mobile dongle I’d love to see it. If you
haven’t, why not? If you’ve any issues please let me know in the