A few years ago, I had this crazy idea to shoot a five-hour exposure while I was camping near the Tetons in Wyoming. The major obstacle to making a picture like this is battery power. The whole time a long exposure is recording, the sensor is activated, the shutter is held open, and a DSLR’s mirror is held up, all of which require power. What’s more, if you use the built-in ‘long exposure noise reduction’ setting, the camera will process the photo for the same amount of time that the shutter was open. That means if I started the picture before bedtime, it’d be finished cooking about the same time breakfast was finished cooking. To my knowledge, there’s not a single camera battery that will last for ten hours of processing.

In the past, this meant you had to get an AC adapter for your camera. It’s a dongle that replaces the battery in the camera and has a cord that plugs into the wall. Trouble is, there aren’t usually a lot of walls with power when camping. So, I also used the big battery pack I use for my strobes to power the camera all night. This power solution worked well enough, but it weighed several pounds and cost several hundred dollars.

Well, TetherTools has a new system that can help to power a camera for a long time, and it won’t break the bank. I wish it had been around when I tried to make my picture. Unfortunately, the moon came out and made my picture so bright it’s like noonday with some streaks of stars in the sky, and it’s not worth showing here. Let’s talk about TetherTools’s new Case Relay power solution and some tips for long exposure situations.


Case Relay

Like a traditional AC adapter, the Case Relay replaces your camera’s battery and lets you plug it into something else. The major advantage to TetherTools’s system is that instead of an AC wall socket, this little tool lets you plug your camera into any USB jack. That is marvelous. I can plug it into the same block I use for my phone, or use a USB adapter in the car, or the computer, or, best of all, I can plug it into a USB battery.


USB Battery Advantages

USB battery packs are readily available for charging mobile devices on the go, so this is a perfect solution for powering a camera. USB batteries range from $20 to $80 depending on how much power they can hold and how durable they are. Batteries for Nikons, Canons, and my Lumix GH4 hold between 1800mAh, and 1900mAh (mAh= milliamp hours; it’s just a measure of how much power is in a battery). A cheap USB battery holds 10,000mAh. So this, Case Relay lets me shoot for more than 5 times as long as a camera battery.


Not only does the Case Relay connect to a USB battery, it also has a 1200mAh battery built in. That means when my USB battery is getting low, I can simply unplug it and plug in a new one without interrupting camera operation. I can keep my long exposure, or my time-lapse, or my video running continuously. In fact, the built-in battery recharges itself off the new battery, so you’ve always got that as a backup when your USB dies. Changing a battery like this without stopping the camera is called ‘hot-swapping.’

What You Need

To get your camera running, you need to buy the Case Relay and the DC Camera Coupler made for your specific camera body. They plug into one another, so you could use the same Case Relay with different cameras if you buy the couplers for those other cameras. TetherTools sells both pieces in a kit; get the right kit for your camera (see the ‘Compatibility’ tab at the bottom of the link). More cameras will be available in the future.

You can use any USB battery, but TetherTools also sells a battery that I rather like. It’s tough, it looks good, and it seems very reliable. It sits at the high end of price for batteries, but I’ve found you get what you pay for when it comes to batteries, and I recommend this one. It’s called the Rock Solid External Battery Pack, and I also recommend the silicon cover.

TetherTools are known for making accessories which perfectly meet the needs for tethering your camera to another device. While the Case Relay and a battery are all you need, you’ll have an easier time of it if you also get the Strap Moore to hold the battery on your tripod. You can figure out another way to do it, but TetherTools already did, and it’s perfect.

I used the Case Relay system to power my camera for 14 hours while driving from Utah to Oregon. I secured my Lumix GH4 to the dashboard with my Platypod Pro and used the Case Relay plugged into the car’s USB outlet for power. The built-in battery let my time-lapse keep going even when I shut off the car for meals and fuel breaks. I think that’s pretty rad. 

This video condenses the 12-hour drive on Interstate Highway 84 from Utah to Oregon to four minutes. I learned a few good lessons, which I relate below.


So, US$99 for the Case Relay plus, the coupler (up to $35), plus a USB battery. $185 total, if you use the TetherTools battery. That’s a lot less costly than my previous setup, and I can use the battery for charging my other devices. It lasts fives times longer than a camera battery, and it costs less than 3 camera batteries; that’s a good deal.

With these tools, you’re ready to make pictures or videos for a long, long time. But I’ve got a few other ideas for you to consider.

Don’t Forget…

Here are a few more lessons I’ve learned shooting long exposures, videos, and time-lapse:

  • Memory cards fill quickly. Make sure yours is big enough and format it in the camera before you begin. Conser reducing the quality or resolution of your pictures so you get enough pictures on your card.
  • Setup out of the way. The spot you’re in may not be busy when you begin, but will there be people tripping over your tripod in an hour or two when the business day ends? Will the sun end up shining directly into your lens?
  • Stabilize your tripod. Just as people may end up in your way, the wind might start blowing and if you try to add weight to your tripod later, you’ll end up bumping it and that ruins a long exposure or time-lapse and wastes all the time you’ve spent to that point. Add weight before you begin.
  • Practice your timing. In my hyper-lapse while driving, I made the interval between shots too long, and the video isn’t as fluid as I’d have liked. I used 5 seconds, but I think 3 seconds would have been better.
  • Remember to use manual focus. Anytime you shoot a time-lapse you should focus, then switch the camera to manual so it doesn’t change as trees blow in the breeze, or people walk by, or while driving the car.
  • Use PhotoPills, SunSeeker, The Photographer’s Ephemeris or similar tools to plan where the sun, moon, and stars will be during your long exposure. Don’t let yourself be surprised by a moonrise in the middle of your picture like I was.
  • Bring a book. You’ll be sitting with your camera for a long time, so use the time to catch up on your reading. There are several book reviews on Photofocus.com to get you started.


Whether you’re shooting long exposures, time-lapse, or video, proper prior planning will ensure your picture making goes smoothly. That means preparing to power your camera, as well as planning for all the little changes that will happen while you shoot. The TetherTools Case Relay system is a good way to power your tools for the long haul. Just be sure to prepare for all the other stuff, too.