Read the product pages of today’s flagship dash cams and you’ll be convinced the next must-have feature is a 60fps video. Double what most dash cams offered until recently, 60fps promises to create smoother video that should, in theory at least, retain more detail when slowed down – perfect for spotting a key piece of evidence, like a road marking, street sign or vehicle licence plate, should you be caught up in a collision.
Some of the best dash cams let you pick between two different frame rates, just as other models also let you choose from various resolutions. Often, a higher frame rate is only possible with a lower resolution. For example, the Viofo A229 can record 4K at 30fps (that’s frames per second), or 1440p at 60fps. Some, like the Garmin X310, even go right up to 120fps, but the resolution then falls to 1080p.
Only very recently have dash cams had the ability to shoot 4K video at 60fps. But should you pick this option? Or should you dive into the settings menu and record 4K at 30fps instead? To find out whether 60fps really makes a difference, I’m using the Viofo A329, a high-end dash cam that gives the user a choice of 4K at 30 or 60fps.
I installed the dash cam in my car and completed several journeys using both frame rate options. The camera resolution was set to 4K and I left all of its other settings in their default configuration. Since it is included with the A329, I fitted Viofo’s polarizing lens filter, which aims to cut down on windshield reflections.
Low-speed driving: 30 fps vs 60 fps
Given I live in London, surrounded by 20mph roads, my first test involved low-speed town and city driving. To make the test as fair as possible, I drove the same route twice. I first set the dash cam to its default 4K at 60fps, then changed it to 4K at 30fps. I then transferred the footage to my computer for a closer look (see below).
Viewed at normal speed, both videos appear sharp and smooth, with plenty of detail. They won’t win an Oscar, and despite its high specification the A329 produces fairly flat footage that lacks saturation. But the recordings are pretty much identical.
Details like licence plates and road signs are clearly visible, especially when the footage is paused. I occasionally had to scrub back and forth through a few frames of the 30fps sample to get a clear view of vehicles passing in the opposite direction, but otherwise the video is perfectly clear and usable.
Slow the footage down to half-speed though, and the difference between 30 fps and 60fps becomes clear. Since there are twice as many frames in the second recording, it remains smooth when slowed down by 50 percent, whereas the 30fps footage stutters. Every frame is still there, and it’s still unlikely that key details could be entirely lost due to the lower frame rate. But if you need a slow-motion shot of a high-speed collision or other incident, like a sudden puncture or other mechanical failure, the 60fps option will produce noticeably smoother results.
High-speed driving: 30fps vs 60fps
Next, I headed to the highway to see if there was a more obvious difference between the two frame rates at 70mph. Again, when played at full speed the 30fps and 60fps recordings looked very similar.
But, as expected, when slowed down to half-speed it was the 60fps video that played more smoothly. I was actually quite impressed by how smooth, almost cinematic, the 60fps footage looked when slowed right down. Naturally, driving at a higher speed means more distance is covered in each frame of the recording. A higher frame rate means key details stay in shot for more frames, giving you more opportunities to see them clearly.
Both samples retained a lot of detail, but had I driven on a 60mph main road with no central barrier, the 60fps setting would stand a much better chance of showing the license plates of oncoming vehicles.
Lastly, there’s a difference in file size. Using the same Viofo A329 dash cam, a one-minute recording at 4K and 30fps weighed in at about 320MB, while upping the frame rate to 60 took the file size to about 540MB.
To conclude, while the differences are small, I would recommend switching to a higher frame rate if your dash cam offers it, since the resulting footage is slightly improved, especially when slowed down.
However, I would think twice if upping the frame rate lowered the resolution, since some dash cams fall down from 1440p to 1080p, or from 4K to 1440p or 1080p, when increasing the frame rate. It’s also worth checking how your dash cam performs at night, since in theory a faster frame rate means less light hitting the sensor, and potentially less detailed footage. Ultimately, I would set the dash cam to its highest resolution, then look to increase the frame rate, but only if the resolution stays at 1440p (2K) or above.
