blackest Loc: Ireland

Do I need to explain what an action camera is? I think most of us have seen the go pro cameras. primarily designed for video (up to 4k 60 fps) and various pixel sizes. The top of the market gopro hero black is a 12 Mpix camera some are 20 Mpix and other sizes. Sensor size varies also.

capabilities vary some save in raw , most do not focus, but thats not necessarily a problem. The focal length is around 4mm with a very wide field of view. The hyperfocal distance is around 14 inches which pretty much gives focus from 7inches to infinity.

There is a company making aftermarket lenses for around $100 ( action cams tend to be based on a 12mm threaded lens which is locked with glue at infinity focus) these can focus from around an inch to infinity. A longer focal length reduces distortion at the edges, "the fish eye effect" that can be seen at times (the camera's software normally corrects for most of this).

Cameras can include wifi, bluetooth, voice control, hdmi, raw dng files and various white balance and color profiles, iso settings , spot and matrix center weighted metering.

Prices vary from $50 or less to around $500 many are rebadged at the low end. Many have electronic image stabilization, Sony action cams tend to have optical image stabilization. Electronic image stabilization has positives and negatives. it basically reduces the frame size and moves the frame to compensate for movement (there are gyroscopes built in) the camera knows how far its been moved in each direction. The downside is if say panning vertically you can get jerky movement as it tries to keep the camera level and gives up. A gimbal is better and for an action cam pretty affordable (they are pretty light weight) If you want to create cinematic footage motion blur confuses the camera electronic image stabilization (its trying to keep everything sharp).

Cameras with wifi can usually be controlled from a smart phone app. This makes it possible to say attach the camera to a pole and get view points you could not get normallly and see what the camera is viewing. Gimbal control can let you angle the camera where you want it.

Most actioncams do not have a filter ring although some housings do. The lenses tend to be fairly fast at f2.8 or so. which can lead to very high shutter speeds which for video can result in jerky footage. With a housing that can take an nd filter you can get much better results.

Night time footage tends to be a weak point, this is where a 12 Mpix sensor will be cleaner in lowlight than a 20 Mpix sensor.

Wifi is a plus in an action cam allowing for remote operation settings and even live streaming.
audio quality can be a bit hit and miss if you have a waterproof housing then built in microphones are going to be muffled. Some audio can have clicks and other strange noises, especially on a cheap actioncam.

Apart from Video why might you want an action cam?
They are very light weight and can easily be carried in a shirt pocket, they are not too noticeable and can be a good street photographers camera with such a wide focus most shots can be easily achieved. Having raw available can give you the possibility of getting a very good white balance.
They can get to places you just wouldn't want to risk a dslr.
Many can double up as a dashcam which can be also useful at times.

Good brands include GoPro DJI (most wellknown for drone cameras) xaomi yi (xaomi is the parent company of YI and manufactures its own hardware its also quite hackable you can increase bit rate and other things that can really improve IQ) Sony and
Nikon both make actioncams unfortunately Nikons cameras haven't been that great.

I'll leave this here for now, I will try and answer questions that you may have. I've had to do a fair amount of research to figure out whats worth buying and what to skip. My choice has been the YI 4K plus and i'll explain that choice in another post.

Terrymac Loc: LONDON U.K.

Very interesting and helpful post. Thanks.

berchman Loc: South Central PA

I bought a Sony a year ago. The menu choices are very hard to read from the LCD screen. The extra cost lens protector is easily dislodged. The waterproof housing cuts out the sound if you're using the built-in mike. I have never gotten comfortable with using the camera and had to have a guide at Iguazu Falls figure out how to turn on the record. It does take quality video but so does my iPhone X and the latter is far easier to use.

mikegreenwald Loc: Illinois

Excellent and helpful explanation!
What about battery life?

blackest Loc: Ireland

it depends, most seem to aim for an hour or two of video shooting. Some supply a second or third battery some have a built in battery that can't be replaced.

I read on one cam a power rating of 5 watts so 5volt at 1 amp or a 1000mA battery should last an hour typically 1450mA battery is supplied, should do 90 minutes, try and keep batteries warm if you want to film in snow. Battery charge will dissipate quickly in freezing weather.

Batteries can be hard to find or pretty easy like panasonic. Most seem to use mini / micro or usb type c connectors for data transfer and charging.
some will be happy with a battery booster pack but it depends on the housing you use.

Housings can be Gopro sized but not all action cams mimic the Gopro dimensions.

with a housing designed to be waterproof to a depth of 40 meters you will have no way to charge and audio may only have a muffled scream as you get attacked by sharks but the picture quality can be really good with an under water white balance selected.

with no filter thread on the lens, lenscaps are generally not included.

This case is cnc machined aluminium has a thread for a 37mm filter or cap it is held captive with a 1/4 20 tripod screw. It has the "Gopro" mount so ties into a huge eco system of accessories. There are versions with a 40.5 mm ring size. I wanted the 37mm because i have a moondog anamorphic lens that should fit it along with nd filters to suit.

Having the handy 1/4 20 thread means you can use a standard quick release plate if thats your preference. These are so light a dollar store tripod is good enough.

Ebay no 132808590459

(Download)

RichardTaylor Loc: Sydney, Australia

In the historic motor racing world down here, lot of teams have them attached to the race cars. The video is used for memories, and race analysis.

Tomcat5133 Loc: Gladwyne PA

This is great blackest. i recently shot a huge running festival with camcorder and mirrorless. And was supported by a national company that does quick review of races with action cams. Most GoPro users
are in 4k mode and their is a jittery look to the footage. Great to capture shots on a pole or in the case
they shot some running in the festival where are couldnt to with my team.
I used to go to NAB and GoPro was the star of the show at times. The footage looked better to me then.
Also the look of the footage and matching it with 10 bit Sony camcorders does not go well.
I think the Sony action cams might be bit better.
If I have to do some of this kind of shooting which camera would you use first.
This post if very useful. Thanks for your contribution. Tom

blackest Loc: Ireland

yes they are kind of doing it wrong.
Electronic image stabilization is a bit better than none but its trying to keep the frame steady which is ok till you want to move and it fights you and then suddenly gives up and then starts fighting over the next bit of framing. The other problem is a fixed f2.8 lens it can shift iso and shutter speed but if the shutter speed is high it gets to be a bit like an old flick book as the shutter speed increases best speed is around double the frame rate so 24 fps should be at 1/48th in practice the shutter speed may go to a 1/1000th or less so you only see around 25/thousands of a second for 975/1000ths the shutter is closed so its going to get a bit strobe like. The answer is to use an nd filter to lower the light.

Actioncam is hard to get the control we are used to, but with a little work its quite a nice bit of kit. Not as good as a red or arri but then its a lot less money.

blackest Loc: Ireland

Ok my Yi 4K plus arrived today.
here is a sample, edited on my old iPad

https://youtu.be/jpVGEIb5a-Y

DJphoto Loc: SF Bay Area

I wanted an action cam about 4 or 5 years ago and the Go-Pros didn't seem very substantial and didn't have a viewfinder. I bought a Garmin that seemed much more robust for about the same price and it has been a great camera. My normal use is on a suction cup mount shooting in time-lapse mode through my windshield on road trips, but I've also used it at normal video speed and under water in a Garmin enclosure.

blackest Loc: Ireland

lack of viewfinder is a small downside they do tend to have a rear screen. Shooting 4k you can tidy things up in post a lot if you use 1080p for the final video.