I can film anything or anyone on the public highway, on a public beach, public footpath. I can film anyone on the public highway from my windows.
I can stand on the public highway and film you in your garden, or inside your house.
I can't come on to your land and film without the landowner's permission.
I can film anybody in a public park, theatre, school, business, zoo, swimming pool, shop etc that I have access to unless there is a sign stating 'no photography/filming allowed'.
I am not allowed to cause anyone alarm, harassment or distress so I must stop filming if I am asked to.
If I do take a photo or make a recording the copyright is mine, to do with as I like - so long as I don't cause alarm, harassment or distress or use it to libel or slander or any other illegal purpose.
I cannot take covert photos or films for voyeuristic purposes - but it would have to be proven that sexual stimulation was my motivation for taking the photos or recordings.
As already stated, an individual taking photographs or making videos is not subjected to the Data Protection Act.