Shooting on the GoPro Hero HD
Happy New Year folks. I’ve not posted here for a few months now as things have been pretty busy, but I wanted to write a short blogpost about using the GoPro Hero HD camera.
Last November I took a break in Dahab, Egypt. It’s a great place to windsurf, mainly because it’s a damn sight warmer than over here in the UK, but it also has a large lagoon which protects the main bay from any swell and stops you getting swept out to sea (kinda handy!).
I was over there two years before and managed to get some great shots with my old Canon 300D of some of the pro’s doing various tricks like the “Grubby” pictured below (This is what it should look like).
A word of warning for anyone doing much travelling at the moment. It seems that some of the airlines leaving the UK are getting quite strict about carry-on baggage weight. I’m a bit of a gadget freak, and I don’t particularly trust the baggage handling system, so my carry-on bag had a Macbook Pro, iPad, Canon 5D MkII (with two lenses) and the GoPro HD camera. The check-in girl took one look at the straining shoulder strap and weighed it in at about 13 kilos which is over half the weight of the hold luggage limit! So yes, they made me repack. You have been warned!
So before I went away I bought a GoPro HD. A friend of mine at The Mill had used one on his skiing holiday and it looked pretty awesome. I also saw this great video by GoPro themselves here which is well worth a watch.
They’re not particularly cheap (£269 for the basic set), so I guess it’s understandable that I was a little protective over it the first time I took it out on the water. I had a bit of blast around on the windsurfer, took a look at it and noticed that it wasn’t switched on anymore. I could see that there was water condensation inside the casing too, at which point I assumed the worst and figured that the case had leaked water and shorted out the camera.
Anyway, it turned out that the camera was fine. Apparently, the one issue with the GoPro is that the water tight casing means that changes in temperature can cause condensation to form. The camera had just turned itself off after it had reached the 3.4Gb file size limit and stopped recording (more on this below). GoPro sell anti-fog strips that you can buy that stop fogging from happening, but don’t bother, there are some simple steps you can take that will guarantee you won’t get any fogging and it won’t cost you a penny.
Right, so in the time honoured tradition of internet blogging; here are 10 tips and tricks for making the GoPro work for you:
Condensation is formed when warm humid air meets a cold surface. In my situation, I shut the camera case when it was on dry land in the warm humid air and as soon as the camera got wet, the clear perspex case cooled and condensation formed, resulting in a blurred washed out image. Not nice!
As I mentioned above, you can use the GoPro anti-fog strips, but otherwise you just need a source of dry cool air. An air-conditioning unit is perfect for this, or a fridge. Whatever you use, expose the case to the cool air for a minute, put the camera inside, and carefully shut the case. As an added precaution, put a small piece of toilet tissue behind the camera. That should make sure you won’t get any condensation at all. Doing this everyday before I went out worked perfectly. (Thanks to the GoPro forums for this tip)
Closing the case
The case is what keeps your £270 camera from annihilation by salty water so it pays to look after the mechanism that keeps it shut. The clip that holds the case shut is made of pretty sturdy stuff. However, it’s plastic, so it’s vulnerable to UV damage from the sun that can cause it to become brittle. Knowing how to shut the case in a way that applies a minimum stress on the clip is a good idea.
One of the users on the GoPro forums shows the proper way to do it:
Another thing to check is the casing’s rubber seal. It’s is the last defence against water getting into the case so you need to treat it with care. It’s always worth just giving it a wipe after being on the beach to make sure you don’t get any sand in it. Hairs getting trapped are another thing to watch out for.
Tether it because it doesn’t float!
You might be surprised to know that no component of the camera system or mounting brackets float. That’s right. It all sinks. Like a stone.
That’s why it’s essential to tether your camera in some way to something that does float, whether that’s you, your windsurfer, or your rig. This is especially important if you ever wear the camera on your head using the head strap mount. If you get catapulted, you can expect to see your camera bouncing across the water Barnes Wallis style if you don’t have it fixed to you in some way. Generally, you need to keep the tether short so you don’t get strangled, but enough to give it some play.
Tighten the screws as much as you can
The black plastic clamps that fix the camera to the windsurfer mast or boom can flex by quite a lot, but it’s surprisingly tough. You may be scared to tighten the screws too much as it can look as if you’re going to break the clamp, but it’s actually fine. If you don’t tighten it properly, the flexibility can mean that the camera can slip during filming.
If you watch my video at the bottom of this article, you’ll notice I hit a bit of chop at 1:01 that causes the camera to nod down a few degrees because I didn’t tighten it fully. Oops.
Know your hardware limits
I bought my GoPro with a 16Gb memory card. That’s enough space for about 2 hours of HD footage. As I mentioned above, there’s a 3.4Gb limit on the file size that can be written to the cards (something which is apparently to be fixed by GoPro), so that means a maximum of approximately 30 minutes of continuous video.
It’s easy to let the camera just run, but unless you keep track of how long it’s been recording, then you run the risk of the camera stopping on you and missing some awesome shots. Unfortunately I learnt this from bitter experience!
Before every trip out on the windsurfer, I’d start the camera. As soon as I got back, I’d stop it again. Each session lasted on average about 10 minutes so it made sure I always captured the action.
Short takes for easy editing
As a result of the previous point; keeping your takes short makes life a lot easier in post when it comes to editing it all together. Instead of having to trawl through a huge 3.4Gb video file, you can do a lot of culling of unwanted footage by just deleting files.
Keeping file size down
There’s another reason to not let your GoPro camera record for the maximum duration. The longer it records for, the greater the chance exists of a file getting corrupted as it can occasionally write bad data to the movie file. This only happened to me once in a weeks worth of recording and it’s hardly unexpected considering the extreme conditions and motion the camera gets exposed to.
It’s not a complete disaster though, as it is possible to recover most of the corrupted footage (see below).
When you get your camera, check to see if it has PAL support. If not, go to here and download the latest update. There are a few other additions to the software, but the PAL support is probably the most useful.
Recovering corrupt videos
As mentioned above, the GoPro can occasionally corrupt videos. The good news is that there’s a Perl script that can fix it for you. You can download the original script from this forum post.
One thing to note is that the script doesn’t directly support the PAL formats, However it’s a fairly simple fix to change the script yourself. You just need to change the $framerate variables at the top from 30 to 25, and from 60 to 50 and it works. (If you can’t figure it out, drop a comment below and I’ll go into more detail).
If you do this, you’ll find that you should be able to play the file in VLC, but other programs might still have issues opening the video. This may or may not be a problem depending what you’re wanting to do with it.
Oh, and you’ll also lose audio, but that’s not generally a problem since capturing audio through the waterproof casing is something you’ll rarely want to do anyway.
Resolution and implications
I initially started shooting with full 1920×1080 HD, but ended up switching to 1280×960. Why? Three reasons.
- Firstly it let me reduce the file size, so I could shoot more footage and have less issues with corruption.
- Secondly, the full HD refused to load into After Effects whereas the 960p could be loaded directly. I believe you can convert the 1080p using Mpeg Streamclip into a format that After Effects will load, but I’ve not tried it yet.
- Finally, the format you use results in a different field of view being captured. Footage shot at 1280×960 has a field of view of 170º compared to that at full 1920×1080 HD which has a 25% narrower field of view at 127º. I felt that the wider angle worked better for the shot from the mast so I went with the 960p. Here’s a link to the PDF of the manual. It shows the full range of resolutions that the camera supports.
From tests I did at 960p, it could be resized up to full 1080p and sharpened slightly to give a very similar result. I need to do a few more experiments with this though, so I’ll post the results up here when I do.
So, here’s the video. You’ll notice that it isn’t as sharp as the GoPro skiing video. I expect that that’s partly down to the fact that I used 960p, but it’s also because I rotated (and therefore cropped) the image to make the camera angle a little more natural.
Thanks again go to the users at the GoPro forum. There’s a wealth of information over there, so go check it out.