All the above AND.....
Something such as a video camera can be rather bukly and solid, if there was a sudden impact or even breaking while the aircraft is taking off/landing then a video camera could become a possibly lethal missile in the cabin should you let go of it!!! It should be safely stowed in the overhead bins or in a bag under your seat. Also, if you are using a video cam your concentration will be occuppied with whatever you are recording so if something happens you may not be as immediately aware and thus hamper any precautionary action!!! Take for example the Air France evac a few months ago, how many people must have sat in their seats or blocked the aisles from evacuating pax and crew so that they could switch on their phone, wait for it to load and then take pictures of the interior...imagine what you would be doing if you had a video camera. It may be great to sell to the news agencies but it could be so dangerous if you prevented people or yourself from evacuating! Thank god the Air France flight did evacuate without any problems. Of course, you are allowed to use video cams onboard but it is suggested you ask any strangers/passengers and crew if it is ok to video them or parts of the plane as this is considered polite and in this day and age, crew have to look upon people suspiciously and report odd happenings to the captain! If a complaint comes in from another passenger then Im afraid the crew would more than likely tell you to stop recording and put it away!!!