Gopro 10, why 30 or 60 fps for underwater?

[WouterB]

Hi,

I am new to diving, but have been filming for awhile now. I keep reading that it is advised to set a camera to 30 or 60 fps for underwater video.
But I do not really understand why. There is allways less light below the water, and the higher the framerate, the less time each frame has for exposure on the sensor.
With 60 vs 24 fps, the time for exposure is more than doubled with 24 fps. Using 24 fps should mean lower iso and less grainy footage.

What am I missing, why is the advise for low light shooting on land "the lower the fps the better, meaning 24 fps", but for underwater I keep reading 30 or 60 fps.

What am I not understanding/missing?

Wouter

 

[El Diablo]

Hi,

I am new to diving, but have been filming for awhile now. I keep reading that it is advised to set a camera to 30 or 60 fps for underwater video.
But I do not really understand why. There is allways less light below the water, and the higher the framerate, the less time each frame has for exposure on the sensor.
With 60 vs 24 fps, the time for exposure is more than doubled with 24 fps. Using 24 fps should mean lower iso and less grainy footage.

What am I missing, why is the advise for low light shooting on land "the lower the fps the better, meaning 24 fps", but for underwater I keep reading 30 or 60 fps.

What am I not understanding/missing?

Wouter

Hi Wouter,

Filming at 60 fps will give you the option to further slow down your UW footage if you export it on a 24 or 30 fps timeline. Slowing down the recording also means that your videos will look smoother and less shaky because the electronic stabilization doesn't work so well underwater and you will be introducing movement just by fining no matter how slow you go. If there are currents they will also shake your camera.

However, this means that you are willing to edit your videos and spend some time. If you do not wish to edit your videos, 24 fps for a more cinematic look or 30 fps work also fine.

As a bonus and IF you use a desktop or Mac, GoPro use a software called ReelSteady that automatically stabilizes your videos with amazing results. I believe its free but don't quote me on this as the last years I use a DJI Osmo.

You are totally right about the exposure triangle, if you are going deep you might see some grain. Personally I've filmed a couple wrecks around 40m depth in the Madeira islands with quite low viz and the 60fps were no issue for me. Of course, you need to test what values your auto ISO reaches as above 400 all these action cams have lots of noise.

ps. Be sure to get a good grip or tray to help you keep the GoPro as stable as possible while fining. Also as I guess you'll be diving below 10m, get a red filter (if diving in seawater, magenta if green lake water) otherwise your white balance will be all over the place

Link to: ReelSteady

 

[WouterB]

Thanks for your answer. I assume you used lights when filming at 40 m?

 

[Diver With Altitude]

Higher frame rates are recommended when your subjects are in motion. The pre-set Activity settings on my GP 10 are 4K/60 fps. I saw a YouTube how-to that recommended 120 fps, switching to 60 fps when you get deeper.

 

[El Diablo]

Thanks for your answer. I assume you used lights when filming at 40 m?

You are welcome, no lights, I kept it as simple as possible.

 

[El Diablo]

Higher frame rates are recommended when your subjects are in motion. The pre-set Activity settings on my GP 10 are 4K/60 fps. I saw a YouTube how-to that recommended 120 fps, switching to 60 fps when you get deeper.

120 fps UW is a hyperbole unless you want to slow down the speed to 25% the original.

 

[Diver With Altitude]

120 fps UW is a hyperbole unless you want to slow down the speed to 25% the original.

One of the videos I watched suggested that a lot of underwater scenes look good in slow motion. I'm just starting to experiment with settings.

 

[Dan]

120 fps UW is a hyperbole unless you want to slow down the speed to 25% the original.

That’s the reason I set my GoPro 10 fps to 120, to slow down an action clip to see what just happened, as shown, below.

 

[El Diablo]

That’s the reason I set my GoPro 10 fps to 120, to slow down an action clip to see what just happened, as shown, below.

Hi Dan,

Perhaps you could give some more context to Wouter as what you are doing is slowing down a specific short segment to 'freeze' the action. Shooting the whole video on 120fps will take a huge a mount of space in his Mini SD card / PC and if he has no action sequences that worth slowing down 4 times, basically he will end up with a huge file if he keeps the original frame rate for no apparent reason while probably the sensor will struggle to get enough light OR an extremely slow and boring video where fining 1 time takes 10sec if he decides to drop it on a 24fps for that cinematic look that we previously mentioned...

As you can see on your own footage, the segment that is not slow down looks quite shaky. If you had decided to do so for the whole length, it would take 4m to watch instead of 1mn. What software are you using to combine the 2 timelines?

I still believe that 60pfs is a good compromise to slow down enough the video in order to stabilize micro , jitters or cut too much light. That video you posted looks like the Bahamas (?) so very clear water and perhaps not too deep so light isn't an issue for the high frame rate.

In any case, great video

 

[Dan]

Hi Dan,

Perhaps you could give some more context to Wouter as what you are doing is slowing down a specific short segment to 'freeze' the action. Shooting the whole video on 120fps will take a huge a mount of space in his Mini SD card / PC and if he has no action sequences that worth slowing down 4 times, basically he will end up with a huge file if he keeps the original frame rate for no apparent reason while probably the sensor will struggle to get enough light OR an extremely slow and boring video where fining 1 time takes 10sec if he decides to drop it on a 24fps for that cinematic look that we previously mentioned...

As you can see on your own footage, the segment that is not slow down looks quite shaky. If you had decided to do so for the whole length, it would take 4m to watch instead of 1mn. What software are you using to combine the 2 timelines?

I still believe that 60pfs is a good compromise to slow down enough the video in order to stabilize micro , jitters or cut too much light. That video you posted looks like the Bahamas (?) so very clear water and perhaps not too deep so light isn't an issue for the high frame rate.

In any case, great video

Most of the time I don’t need to slow it down. So I’ll drop the fps to 60 for better video quality then. Thanks for your tips.

I use this video editing Shotcut - Home