 Poster: A snowHead
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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The framerate of only 25fps means that any faster action is going to look jerky. My drift HD (not the latest tech by any stretch of the imagination) records at 30fps at 1080p but 60fps at 720, and I find I really need the 60fps to get the smoothness of action shots. Even the iPhone can handle 120fps now, as well as the latest Drift Ghost S and the GoPro
£89 isn't that cheap, you could probably pick up an early Drift, contour or GoPro for not much more and get better quality video.
The other thing that I think is often overlooked is how temperature affects battery life. It can cripple a camera in only a couple of hours if it's really cold, when it would normally last all day at normal temps. If the whole unit needs charged rather than having interchangeable batteries, then it might prove a waste of time to take it on the hill
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Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
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| feef wrote: |
The framerate of only 25fps means that any faster action is going to look jerky. My drift HD (not the latest tech by any stretch of the imagination) records at 30fps at 1080p but 60fps at 720, and I find I really need the 60fps to get the smoothness of action shots. Even the iPhone can handle 120fps now, as well as the latest Drift Ghost S and the GoPro
£89 isn't that cheap, you could probably pick up an early Drift, contour or GoPro for not much more and get better quality video.
The other thing that I think is often overlooked is how temperature affects battery life. It can cripple a camera in only a couple of hours if it's really cold, when it would normally last all day at normal temps. If the whole unit needs charged rather than having interchangeable batteries, then it might prove a waste of time to take it on the hill |
Thanks for that. Think I'll give it a miss
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You need to Login to know who's really who.
You need to Login to know who's really who.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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The best that can be said is that it is the right shape for a colo-rectal examination and the body heat might help the battery life, splash resistance could be a plus in this environment.
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You'll need to Register first of course.
You'll need to Register first of course.
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| davidof wrote: |
| The best that can be said is that it is the right shape for a colo-rectal examination and the body heat might help the battery life, splash resistance could be a plus in this environment. |
 let us know how you get on
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| feef wrote: |
| The framerate of only 25fps means that any faster action is going to look jerky. |
I think you need to justify/explain that. UK TV is only 25fps and looks fine to my (oldish) eyes.
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| RobW wrote: |
| feef wrote: |
| The framerate of only 25fps means that any faster action is going to look jerky. |
I think you need to justify/explain that. UK TV is only 25fps and looks fine to my (oldish) eyes. |
Interpolation.
The conversion from 120,60 or even 30 down to 25fps allows for some 'smearing' between the frames to help smooth the motion out. If you record at 25fps you have nothing in between to smear.
This is my super-simplified understanding of it. I'm sure someone else will be along to elaborate or just simply correct me.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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feef, it works a bit like this. At 24/25 frames per second for the most part motion will be smooth to the human eye, if you're really concentrating or the image is in your peripheral vision then higher frame rates are noticeably smoother. Keeping the framerate lower obviously saves money but is a historical artefact but this is why we've not seen a push to higher frame rates as it's "not cinematic". There was lots of hoohah over The Hobbit using a higher framerate.
Each frame isn't a moment in time it's a small period of time exactly the same as the exposure time of a photograph. Typically the rule of thumb is to set the exposure time to be half the frame time. This gives "the most pleasant" smearing of motion in the frame. If you have a really low exposure time motion looks more jerky at lower frame rates. So conforming high frame rates to low frame rates can be quite complex if you want to end up with the same sense of smearing (you can't just discard frames). This is further complicated if you need to conform to a frame rate that doesn't divide exactly into the original (e.g. Going from 120 to 25). This isn't so bad though as you have lots of information to work with.
Higher frame rates essentially give more steps so there is more information that let's you slow down the footage easily. If you want to slow down footage at 24fps but keep the resulting video at 24fps then you have a problem as there is no extra information. You have to interpolate between frames which can be very difficult and often gives odd results. Plugins like Twixtor do a really good job but people really have to search for footage it will work with without doing some really weird things. You could just show the frames for a longer period of time but the end result quickly feels jerky.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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TLDR; 25fps is fine for a video camera as long as you don't want to slow the footage down.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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Yet I've found a noticeable difference between 30 and 60fps in how a video looks for the same sort of action. It was noticeably more 'stepped' at 30 and smoother at 60, and that wasn't with slowing anything down. Granted that was on the laptop and not a TV, so I suppose there the difference is more visible?
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feef, probably because you are closer up but maybe because of how the camera is setup itself. If 30fps and 60fps have the same exposure time then 60fps will feel smoother as it'll be more contiguous with the motion blur.
Higher frame rates are generally better but can suffer in encoding quality if the max bitrate is limited. You need more storage space as well!
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You know it makes sense.
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| RobW wrote: |
| feef wrote: |
| The framerate of only 25fps means that any faster action is going to look jerky. |
I think you need to justify/explain that. UK TV is only 25fps and looks fine to my (oldish) eyes. |
UK TV is 25 Frames per second but is also 50 fields per second. This is because uk TV is interlaced and not progressive. Interlaced means a full resolution frame is built from two half resolution images (every other line), these two field images were taken at different times so although from a picture detail point of view we have a full resolution image every 25th of a second from the view of motion portrayal we have a half resolution image ever 50th of a second.
These action cameras are all producing progressive (not interlaced) pictures meaning every fraction of a second you get a full resolution image unlike uk this means a 25fps sequence is only sampling motion every 25fps and hence the poor motion portrayal compared to uk tv.
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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dan-b, it's definitely not the case that each field image was taken at a different time, if it were they wouldn't line up and you get weird artifacts like this which is particular visible with any motion:
^--- this is what you'd get and also end up with if your deinterlacing algorithm is crap.
Most modern TVs go as far as to rebuild the frames and display those in a progressive manner when handling interlaced footage.
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Poster: A snowHead
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| meh wrote: |
feef, probably because you are closer up but maybe because of how the camera is setup itself. If 30fps and 60fps have the same exposure time then 60fps will feel smoother as it'll be more contiguous with the motion blur.
Higher frame rates are generally better but can suffer in encoding quality if the max bitrate is limited. You need more storage space as well! |
Got a 32GB card in my Drift, that can outlast 3 batteries on a cold day on the hill 
I just dump the content to my laptop each evening and start fresh.
I am tempted by the Ghost S, 120fps at 720 will make for some fun slo-mo stuff.
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FAQ
