Hey Banksie,
I will start off by saying Welcome to Cyclechat.
Now the reasons you want a camera are as follows
1) You want to deter/capture any potential harm caused by motorists
2) You want something that looks good and modest.
- Sadly, these reasons contradict themselves. If you want less abuse, it's better to have something to prevent it in the first place.
to do just that, you need something that is visible - as an active deterrent. For this, there is no better place to put a camera than the Helmet.
However, sacrificing the modesty does come with a plus side; not only are you able to deter motorists in the first place, but should anything ever happen anyway you are More able to capture it.
Confining your camera to a "modest" place (such as handlebars) will result in less dynamic footage that can potentially capture important points.
However, if you still want to start slow and put the camera in a less revealing place it is your choice.
If you take this route, you will be treated as per usual and the camera will only serve a use for When something has already happened. - Rather, than deterring it beforehand.
The negative for the modesty is not only the lack of pre-hand deterrent, it's also for when something has occurred. The best place to put your camera is on the handlebars However vibrations are strong from the handlebar and can blur camera quality.
Now let's talk about the ways to get the best of both these worlds.
1) The right cameras
2) How many cameras
If you purchase the Right camera, you can get a good blend of modesty (Well hidden) and ability to capture alot of dynamic footage. (such as, the camera glasses)
However, the quality of these smaller cameras is quite drastic at the low end; so low infact that it's hard for the cameras to pick up number plates in the time of day. - These Cheap (sub <£30.00) Small cameras are best avoided. - Camera glasses are expensive in the whole; any cheaper onces will yield less quality which can be fatal for when you really need the footage.
Your best bet is to purchase a medium tier camera of intermediate scale. Look at the SJ4000 (or even, its chinese copies) for a good blend of price, size and quality.
Now, how many cameras you get is based purely on how much you're willing to spend. Often, it's not uncommon to see 1 expensive camera on the front; and 1 cheapo on the back of a bicycle nowadays.
While that's all good and dandy you should remember that whatever you purchase up front should be spent on the back too. - You can cut corners, but both are equally as important directions to put a camera in.
If you are only going to use one camera it is always advised you point it Forward. - While logically you would assume it'd be best pointed from behind, don't be so sure - this is personal preference to alot of people but in sharp reality you will always capture more potentially unsafe footage in the direction you are going to travel rather than the places you have just travelled.
Now, here are some personal tips from me.
With whatever camera you buy you can play with where you want it. - You don't have to limit yourself; even if it didn't come with the right attachments.
For example, I have my camera installed on the very front of my helmet - SJ4000; I couldn't use the attachments that came with it to do this, instead, I made a brace out of Cable ties; which works incredibly well, keeping it stiff, quiet and also managable for when i need to open the camera out of its waterproof case.
- It also looks very modest. - Being on the front of my helmet means it follows the curves downward - doesn't stick up tall and become a deterrent, but I didn't want it to be so noticeable. - It's literally pinned to the front of the helmet which allows me to capture dynamic footage too.
Bare these things in mind and more importantly take your time.
Note: To some drivers a camera will not be a deterrent at all.