The above image was taken last week at Chinese Arch with a GoPro Hero 12 Black, employing its simple to use "Star Trails" mode.
I promised at the end of last week's post on "5 Ways to Capture Star Trails" that I'd share details one of those five ways (this will be in the presentation on star trails that I'm giving later this month at the Nightscaper Photo Conference). This is ONE of those five ways. GoPro has put all the features you need into the "Star Trails" mode of a little camera that most people only consider as an "action" camera for extreme sports! (Note: the "Star Trails" feature was introduced with the Hero 11, and is not available on earlier models.)
Trail Length Styles: In fact, the camera features three different star trail style "lengths" — the "Max" Trails length style (shown above), a "Short" Trails length style (not shown), and a "Long" (comet-like) Trails length style:
Star Trails Camera Specs: Every time you take a star trails photo with GoPro Hero 12 Black, it gives you both a 27MP (5312 x 4648 pixels) still image and a time lapse video. You can choose between an aspect ratio of 8:7 (almost square) or 16:9 ratio. For the video resolution you can choose between 4K or 5.3K output (choosing 5.3K will allow you to output still frame images at a resolution of 24MP. Images are saved to a MicroSD memory card (a 64GB card is included with your camera purchase). The camera lens angle of view for the Star Trails mode is a super wide 156º when using the 8:7 aspect ratio. I highly recommend this aspect ratio because it gives you the greatest options for cropping both the still image and the video.
In-camera Post-processing. With regular stacked star trail exposures, you have to do hundreds of 30-second exposures (in a time lapse), process all the images in Lightroom, and send them to StarStaX to stack them end-to-end into star trails. GoPro does all that for you. Here's an enlargement of the top image (enlarged to actual pixel size) to show how the GoPro software has stacked some of the 360 30-second exposures in that 3-hour capture. And, it does this in only about 5 seconds after the final exposure!
VIDEOS Time Lapses - Comparing "Max" and "Long" Trail Length Styles: To further compare these two trail length styles, I going to show you time lapse videos of each (a 3-hour recording duration on both, resulting in 12-second videos), starting with the "Max" and ending with the "Long" or 'comet' style (both have been cropped and rendered here to a 1080p resolution):
"Max" Trails length style time lapse VIDEO at Silver Lake (click to view)
"Long" Trails length (comet-like) style time lapse VIDEO at Silver Lake (click to view)
Both of these scenes were recorded at Silver Lake, only 16 miles from Salt Lake City, Utah, where we are still in a very light-polluted environment (about a Bortle 5), and I had a 90% Gibbous Moon behind me.
Three things you should notice in these videos that are very important in how these different style lengths record star trails:
1.) Trail Length comparison. "Max" records the maximum star trail length or arc, whereas "Long" is constantly fading away (tapering into a 'long comet tail'). When I mention "arc," I'm refering to the arc angle that the star trails travel during the duration you choose to record. In this case, the total exposure duration was 3 hours, so the arc angle of the trails around Polaris (North Star) is 45º (the fraction of 3 hours divided by 24 hours, times 360º). I have not shown the "Short" Trails length style (a much shorter 'comet' tail) because I think it is a useless option (in my opinion).
2.) Overall Scene Brightness comparison. Notice how in the "Max" Trails length style the scene remains a constant brightness, whereas in the "Long" Trails length (comet-like) style that the scene starts out bright and becomes darker? This is due to how the two styles record the star trails. "Long" records the scene brightness as it happens. Because the 90% Moon started to go behind a mountain and shade the lake, this darkening of the scene showed up in the time lapse video; and as the Moon began to set below the horizon, the sky behind the stars also began to get darker towards the end of the video (the still photo output will show an average of these two brightnesses). The "Max" not only records the longest trail lengths, but it also records the brightest scene in the time lapse. This maximum scene brightness will remain throughout the whole video and in the still image output.
3.) Fading interference comparison. Compare the airplane trail interference in each of the videos (notice the airplane trail near the horizon). In the "Max" style, once a meteor, car headlights or airplane streaks across the sky or foreground, the original brightness of that interference remains throughout the video or in the final still image. Whereas in the "Long" recording style, those interferences start to fade away as time elapses.
I'll discuss later how these two different recording styles can be a great benefit for how you want your final image to appear.
TUTORIAL for Making Star Trails with the GoPro Hero 12: The Hero 12 has three basic recording modes: Photo, Video and Time Lapse. Starting with the Hero 11, GoPro added a "Star Trails" recording feature within the Time Lapse mode.
Step 1: Choose the "Star Trails" preset within the Time Lapse mode and touch the settings to the right.
Step 2:
Within the Star Trails Settings choose your Aspect Ratio and Resolution. The 8:7 aspect ratio allows more room to crop your final still photo or video (the older Hero 11 had the 4:3 option).
The 5.3K resolution will give you higher resolution stills and video without using a lot of storage space on your memory card.
For Star Trails, there is no lens option: you are stuck with the ultra wide, 156º angle of view that has some fisheye (barrel) distortion. However you can zoom in up to 1.4X (see below in the Capture settings).
Step 3, choose your capture settings:
As I've mentioned previously, for Trail Length you have the options of Max, Long and Short.
Interval is automatic and cannot be changed.
For your shutter speed you have the option of 0.5" second to 30 seconds. For star trail in most dark areas ( about Bortle 1 to Bortle 5), choose 30 seconds. Shorter times can be used in city environments and around airports. Experiment.
You can Schedule a time to start your capture.
The total Duration of your star trails time lapse can be anywhere from 15 seconds to 3 hours. At the end of your preset duration, the camera will automatically stop capturing and process all the images (this only takes about 5 seconds!) into still photo and a time lapse video that you can immediately review. There is also a "No Limit" duration setting, but you have to click the shutter again to stop capturing. Be aware that the internal battery will only give a maximum of about 2 hours of star trails capture time (often only about 1.5 hours), unless you plug your camera into an auxiliary power source (more on this later).
The Timer is a shutter delay (after you press the shutter button) to prevent camera shake. The options are 3 seconds, 10 seconds and no delay. As I mentioned above you are stuck with the ultra wide, 156º angle of view lens; however you can zoom in up to 1.4X.
Step 4: In the Protune settings you can only control the the ISO, everything else is preset, including a 3200K White Balance (makes for dark blue sky backgrounds around the stars). I'll discuss a bit of a workaround for this later on. The camera has a range of ISO 100 to ISO 3200. Setting the Minimum ISO will automatically set the Maximum ISO and vise versa. For star trails, I typically set the ISO to 800. In brighter environments (cityscapes) you may wish to go lower. Increasing your ISO to 3200 can produce unacceptable noise (in my opinion).
Step 5: Compose on a sturdy tripod. Wait for the start of the Nautical Twilight and press the shutter button! (More about choosing the "Nautical Twilight" to start your star trails time lapse in a moment...)
Here are two YouTube videos (both using the older Hero 11, which is slightly different in the settings menu) that may help you, if you like learning from a video:
Powering the Hero 12 for Star Trail Captures Longer Than 1 hour. A 1-hour star trails duration yields 4 seconds of time lapse video. A 2-hour durations produces an 8 second time lapse video. 3 hours give you 12 seconds, and so on. Star trails still photos look pretty cool with even 1 hour of capture duration, but the look even more elegant if you go longer (all my star trail photos shown here have a 3 hour duration). It takes 6 hours duration to make a 90º or quarter arc circle around the polar star. An internal GoPro battery will last through a little over 1.5 hours of star trails duration. If you choose a capture "Duration" of 2 hours or longer, you'll need auxiliary power to your GoPro. A good choice is GoPro's Volta Battery Grip, with will give you up to 5.5 hours of capture time. The grip kit comes with a special battery door that allows the power from the Volta to come through the door and into a USB Type C plug in. This power recharges your camera's internal battery on-the-go.
Designing your own auxiliary power: Sometimes you may need to go longer than 5.5 hours or shoot with two GoPro's simultaneously like I have done. For these instances you'll need to replace the battery door with a USB Pass-Through Door and connect the female USB Type-C connection to an 5-watt USB (at least 2 amp output) auxiliary power source.
My Rig: Here I've attached two GoPro's to a 2-inch aluminum plate via 1/4" bolts and wing nuts (with a Arca-Swiss quick release plate in the middle to attach to the tripod). The USB Type-C cords go to auxiliary 5-watt 2.4 amp Li-ion battery packs. The GoPro on the right is an older Hero 11 that has a different mounting connection than the newer GoPro 12 on the left. This set up allows me to shoot both the "Max" and the "Long" (comet-like) star trails at the same time.
Determining the Best Time to Start Your Star Trails. I've found that GoPro star trails look best if you add a little extra "light" to the sky and foreground. Unlike traditional star trail methods, that often look best in a super-dark environment, the GoPro computer algorithm seems to thrive on a little extra light pollution — be it from city lights, the moon, light painting (or my Low Level Lighting) or twilight, as long as it is subtle and not overdone.
Although you have been told to avoid moonlight and to not start shooting the stars until the Astronomical Dusk in order to get the richest contrast between the sky and the stars, I've found that it is best to start shooting GoPro star trails at beginning of the Nautical Dusk, which is often about 30 minutes prior to the Astro Dusk. You can find theses time on websites like ClearOutside.com or apps like PhotoPills.
Test Exposures: I typically start shooting test exposures about 10-15 minutes before the Nautical Dusk. To do this, I keep the same ISO 800 setting and 30-seconds shutter speed, but reduce my Duration to only 1-minute. Here is an example of what your sky and foreground might look like, once you've reached the proper time to start your star trail capture. At this point I changed the Duration to 3 hours and started my star trails exposure. You may wish to do a shorter or longer Duration:
Warming the foreground: This weathered and gnarled tree on an 11,000 foot (about 3,000 m.) mountain pass was lit with a Lume Cube Panel Mini (set at only 5% intensity) at a distance of about 60 feet (18 m.). The light's White Balance was set to 3200º K to match the GoPro's White Balance setting for star trails. To add extra warmth to the tree, I added a warming gel over the light (effectively dropping the White Balance to about 2400ºK.
The GoPro's amazing DOF: The large limb pointing towards the camera was only 12 inches (30 cm) from the lens — showing the Hero 12's amazing Depth of Field with its f/2.5 fixed focus lens (imagine what flower closeups with star trails would look like with this camera)!
Cover the Blinking Red Status Light: Don't forget to cover the status light with black tape when you are doing extreme closeups (not a problem on regular star trail shots, where the foreground is several feet away). Otherwise that little LED will paint your foreground with red light and ruin your shot (yes, it happened to me on one of my early test shots)!
Correcting "interference" issues. Here is the final 3-hour "Max" Trails capture of the gnarled tree: During the last few minutes of that capture, three teenage photographers discovered my setup and painted it with their bright flashlights and red headlamps, which resulted in this image (kind of cool, but not quite what I had planned):
However, this interference can be corrected by doing one of two things:
1.) Taking the foreground from the Nautical Dusk test exposure still photo and pasting it via a Photoshop layer on top of the disastrous interference results — very similar to doing a twilight blend with a Milky Way photo.
2.) Taking the time lapse video and scrubbing (fast forwarding) it to just before the interference occurred, and output a high-resolution (24MP) still frame from the video. This is a very effect solution to annoying airplane trails that enter the capture. It can be even more effective with "Long" (comet-like) trail style captures, where some of the early airplane trails have faded away, and a new annoying trail appears near the end of the video.
Here's the result of the blend with the Nautical Dusk test exposure:
GoPro Star Trail PROS:
Super simple solution to star trails
Comes with a wide variety of effects
Very inexpensive (currently only US$ 350)
Great Depth of Field (no focus stacking needed)
No post-processing needed for most images
Yields a hi-res still image AND a video time lapse with just one exposure
GoPro Star Trail CONS:
Only one lens focal length (albeit you can zoom in up to 1.4X)
Only one White Balance setting of 3200ºK (albeit many prefer this color balance for star trail skies)
JPEG only output for the still image. The camera is capable of RAW files in other modes, but NOT the star trails mode. However, this was not an issue for me since most of the post-processing was handled in-camera by its onboard computer and software.
Conclusion: Incredible results for such an inexpensive camera. It rivaled the results from my $3,000 mirrorless and DSLR cameras, and it did it with very little post-processing. From now on, I plan to setup a GoPro on a 2nd tripod whenever I'm doing nightscapes!