High frame rates question

[samstock]

I have a question regarding the use of frame rates. I'm planning to buy a GoPro 4 Black or Silver and noticed the main difference (apart from the LCD) are the framerate options. The black edition can shoot with higher frame rates.


I know higher frame rates can be useful for slow motion shots. But is there also a disadvantage with using high frame rates? For example, the black edition can shoot 1080p with frame rates up to 120. What should be a good frame rate to use with underwater filming. Is there any reason apart from slomo shots why you should/shouldn't film with high frame rates?


And another question. I always render my videos to 24 frames. I also see videos on youtube with 50 frames. When/why do you choose 24, 30 or 50 frames?


I hope someone can help my understand this a little better

 

[EL Pistoffo]

Like you said higher frame rates allow for smoother slow motion. I think 60 fps is a good balance unless you want to slow something down a lot. With most standard cameras, a higher frame rate requires a higher minimum shutter speed. Usually, the shutter speed should/will not drop bellow the frame rate, ex. 60 fps - 1/60 minimum, 30 fps -1/30 minimum. The reason this matters is because the lower the shutter speed, the more light the camera can gather in low light situations. Therefore a camera shooting at 30 fps can gather more light than a camera shooting at 120 fps. This is all assuming that the GoPro handles shutter speeds as a proper camera should.

Some YouTube videos might list at 50 fps instead of 60 fps because of the video was shot in the PAL video standard. In the US we use NTSC which consists of frame rates like 30 fps and 60 fps. Europe uses PAL which consists of frame rates like 25 fps and 50 fps. Usually a camera will come as a version of one standard or the other. Rarely will a camera be able to do both. Be sure you get the right version.

I like to shoot at 30 or 60 fps. If your a filmmaker, 24 fps is the norm since that is standard for cinema. It gives a more filmic appearance of motion. It's all depends on your needs. My videos are for viewing on TV's and the internet so i'm good with 30 fps as a final output.

 

[DiverLaura]

Higher frame rates need way more light. 60fps will meet you halfway with regards to light needed and works nicely for swimming pool slow-mo, I shoot almost all pool video (UW segments for music videos or short films) in 60fps (although for higher frame rates I'm using a Panasonic GH4 or FS700) because when it is played back at 1/2 speed it looks the way the clients 'imagine' people should look underwater.

120 underwater can be brutal with regards to how much light you will need.

Also keep in mind when you increase the resolution (like say shooting in 2K or 4K or whatnot) you also increase the lighting needs, so high resolution, high frame rate needs impressive amount of light.

What are you hoping to shoot with it?

 

[samstock]

Thanks for your replies! I'm starting to understand the frame rates a lot better now. I'm mainly filming in tropical waters (Philippines, Indonesia, Thailand, etc), so clear waters with a good visibility. Since slomo shots often look nice in underwater footage I'd say 1080p in 60fps would be a good setting for me.

What is the main use to film in 4K? My videos are mostly for viewing on internet and TV. When you film in 4K or 1080p and you master the video to 1080P with 24 fps,would you see much difference in the final result?

I have to decide if I go for the Black or White edition of the gopro 4, after reading your messages I'd say the Silver edition would be a good choice. But the silver edition can film in 4K with max 15 fps which is not enough I think. I just wonder If I would miss the more advanced options of the black edition.Any tips would be welcome. Thanks in advance!

 

[Shasta_man]

The main use of 4K would be watch on a 4K monitor. Shooting in 4K to always reduce to 1080p would not really help, and could actually reduce quality @ 1080p because you would then use software to reduce multiple pixels to a single pixel in a software program so you would inevitably lose quality in that process rather than just capturing at 1080p initially and not resizing. Of course the main use would be eventually use as 4K, but you'll deal with much bigger files (longer editing time, need more RAM, etc) and have to do the resolution reduction all the time until you switch to all 4K. 4K at 15 fps is useless for most uses so that's not a primary reason to get it unless you like high res slideshows. Shooting in 24 fps to switch to 30 fps is also not a good option because it's not an easy conversion so you can end up with jerky spots or other problems. If your primary use is TV monitors or even computer monitors here in the US, then a 30 fps (29.97 and 59.94 actually) based rate is better for your uses.

 

[EL Pistoffo]

In my experience and that of many videographers, rendering to 1080 from a 4K master results in sharper, more detailed video. This happens because most 1080 camera don't actually resolve 1080 lines from the sensor but less (or something along those lines). I now always try to shoot in native 4K for 1080 output, I love the results. The other huge advantage of shooting 4K for 1080 output is for cropping. You can crop and pan and zoom quite a bit of a 4K video and still have full 1080p sharp video at output because of the larger canvas provided by the higher resolution of 4K.


Though the GoPro is not the best 4K camera you can still reap those benefits. You can also have the same benefits though to a lesser degree if you film at 2.7k. It will also provide sharp 1080 video and allow cropping though not as significant before resolution drops below 1080.


4K at 15 fps is useless but 2.7k at 24 or 30 can work. I think the Hero Silver can do that.


I rented a Hero4 Black a month ago while on a trip in the Caribbean. I also had an Sony RX100IV with me as well. The Hero 4 4k had nothing on the Sony 4K as far as IQ goes. I didn't use the GoPro UW much because I have another setup for that which although only 1080 it has more versatility than the GoPro.


I like 4K so much that when finances allow, I will upgrade to a 4K compact camera for my next UW rig. I stopped using GoPros because of poor or no IS, lack of real macro, and poor low-light performance. For the money though, GoPros are hard to beat.

 

[samstock]

Hm interesting. When I search on the internet I mostly read good comments about downscaling 4k to a final 1080p render. Do more people have experience with rendering 4K footage to 1080p?

 

[DiverLaura]

Echoing what was already stated for most part....

In addition to being stunning on almost any monitor if it's shot well (I don't have a 4K monitor and i can see a difference), shooting in 4K is so that you can crop (and motion stabilize) whilst still being able to deliver 1080p. Meaning you can get 'more' out of your single shot. Example: have you watched an interview or scene that cut back and forth between a close and a wide shot that somehow feels a bit... odd? like its from _exactly_ the same angle? yeah, that is very likely a cropped shot from 4K being used to for the transition.

I shoot 4K when there is work to be done in post (green screen so more detail = better), the client requests it specifically or aforementioned ability to crop. Down side is, file size is massive and if I'm not careful it will bring my poor old editing computer to its knees.

Almost all my current diving video that is being shot with the GH4 (unless i'm shooting in 60fps) is being shot in 4K and then a lot of the time being mixed with 1080p and exported. I do this because I sell footage via stock footage library and if i manage to get some awesome man on the moon shot it can be worth couple bucks more, and mixable with RED footage.

All that said, side by side with enough light, a skilled shooter and a good DSLR there are times that unless you knew up front what it was shot in, say, macro work with 100mm macro on a 5DMK2, many people would be hard pressed to 'see' the difference until they started scaling it up.

Another use with the gopro, if i'm shooting with gopro on DJI Phantom, I shoot 2K so that i can crop out the occasional propeller in the top of screen