What are the laws for photos taken during a commercial flight? Just shooting some clouds outside the window and maybe a small city picture after takeoff. Anything I need to know?
Background: I write as a traveller and not a formal expert, but I have made 50+ flight "legs" on either international carriers or on local carriers within Asia in the last 4 or so years. I take many photos out of airline windows and make a point of reading the rules that each airline has established. I use both a DSLR and smaller point and shoot cameras - the latter mainly for their video capability. I am a professional electrical designer - which 'informs' my opinions on the relative merits of various airlines' policies in this area.
Update - 2015: Recent changes have seen many airlines relax their rules and most are reportedly now more like those listed for Qantas below. With that proviso, much of my prior answer still applies.
A summary answer to your question is:
The actual use of a camera in an aircraft is governed by the regulations of the airline concerned. While no modern camera is probably going to be a danger to the navigation systems, the rules for when you can and can't use them vary by airline, with some having tighter requirements than others.
Q: Do the bans make sense?
I am not sure why QANTAS disallow video cameras with external batteries - it may be due to size, possibility of spark on external contacts (unlikely), prospect of batteries being dropped during changing (unlikely) or ??? Most non purpose built cameras with video capability are not affected by this ban - including essentially all video capable DSLRs.
Modern aircraft electronic systems are designed to be as safe as possible against the sort of threats which they may reasonably encounter during flight. As passengers are quite likely to use cellphones in flight despite bans on use, the aircraft systems MUST be proof against such use. The focused beam from a high power RADAR system can inject signals well above what a cellphone can achieve. (In another lifetime when I worked for Telecom NZ, we had an experience where a US warship docked in our capital city and left its main RADAR system scanning. ALL the phones in the city "tinkled" every time the RADAR beam swept across the main telephone exchange :-). The level of EMI generated by a camera under worst case conditions will be far lower than from eg a cellphone. (Assume no super in-camera WifI transmitters etc). So the use of a camera during takeoff and landing is very very very unlikely to pose a hazard of any sort to any aircraft system. Electronic equipment that is allowed to remain operational may present more of a hazard than a camera does. While computers, pdas, "tablets", electronic games, cellphone and smart phones in flight mode and more are required to be turned off during takeoff and landing, items such as watches, pacemakers (fortunately) and miscellaneous items of portable non-display-equipped electronic equipment are exempt or overlooked.
However, "rules are rules" and, while QANTAS allow it, and common sense says it does no harm, getting most other airlines to agree to in-aircraft camera use is "problemantic" at best.
All the normal social 'rules' apply, plus anything laid down by the airline, plus whatever the cabin staff may decide to add if they are having a bad day.
I find that in most cases if I choose to I can end up with most of the cabin staff in the rear galley for a group photo at some stage during the flight. On one occasion I managed most of the cabin staff PlUS the airline's safety training manager, plus an offer of personal assistance with finding sightseeing destinations next time I visited their country.
I have had no problems from staff while taking in-cabin photos of passengers with their permission. Not something I do a vast amount - but often enough to note staff reaction.
On a very few occasions the staff have got grumpy about general in cabin photography (which I try hard to keep to a minimum for trip record or whole cabin pictorial shots only). and suggested I limit in cabin shots BUT I generally don't take more than a few impressions and usually from the back looking forward, if I am not taking personal photos with permission. (Rear of cabin looking forwards with lights off and many monitors on looks good).
(1) Fly QANTAS :-)
(2) Otherwise, what you choose to do is up to you - and exceeding limits may cause you to end up in court. I have seen numerous people using 'point and shoot' cameras during takeoff and landing without airline staff complaint. A film SLR could probably be used and would probably not be seen as an "electronic device" even though almost all would be. A DSLR without LCD enabled may or may not be seen by airline staff as "electronic". The most likely interference from such would probably be the rather large current spike that occurs at shutter operation. The motor drive on a film camera would be worse.
Apart from airline staff reaction you need to assess for yourself the morality of using a device which the airline has banned on "safety" grounds - no matter how reasonable such concerns may or may not be.
My experiences in recent years have been limited to "Pacific Rim" / Asia and a limited number of airlines. However, I believe that they would apply to most reasonably major airlines in many countries.
2004-2012: NZ, Australia, Singapore, Malaysia, Indonesia, Hing Kong, China.
Often poor :-(.
Papua New Guinea - Sensor needs cleaning :-(
North Eastern China - Flying from Urumqi in Xinjiang (top left hand side of China west of Mongolia) towards Hong Kong. Looking towards Himalayas and Everest somewhere far beyond seeing distance. China is almost never this clear at this altitude - even in the far North West.
Definitely not China !
Crossing Australia from NZ heading for Asia - somewhere in inland Queensland - probably at about 35,000 feet. Colours are sure to be wrong but no amount of playing gave anything convincingly better. Manifestly too much yellow - but less looked worse :-(. Australian scorched earth summers plus irrigation tend to get extreme brown and green combinations - but not this extreme (probably). Double optically poor windows do not help. (At this altitude anywhere in China essentially all ground detail would be lost or fully invisible.
Still beautiful - double windows and all. Somewhere between Brunei and Hong Kong.
In addition to Russell's excellent and extensive response, I wanted to note that I have - on at least a dozen occasions - flagrantly used a large Nikon D300 DSLR (sometimes with the 70-200mm f/2.8 lens!) during takeoff and landing on a variety of major airlines, being quite aware that it's incapable of harming anything. I think this is the best time to take photos because you're closer to the ground - objects are closer, the angle is better, and there's less atmospheric haze. The airport tarmac is also full of great shots. The staff have never asked me to stop or even commented on it, although I'm sure they noticed the mirror clap sounds. Obviously if staff do ask you to stop, it is important to comply with instructions.
It helps to turn off image review and not review images until later - staff are trained to look for shining LCD screens (although that's not really an option with mirrorless/P&S). Also if your camera or memory card has any kind of radio transmitting feature like wifi it's a good idea to turn that off.
Finally, as a side note, I recommend a low light lens with a large surface area - the crappy plastic windows of commercial airliners are often heavily scratched or otherwise defective and absorb a lot of light, but a large lens that is nearly touching the window will make a lot of those defects invisible. Additionally the cabin interior is poorly lit so you'd need fast glass or VR to shoot it.
In Norway the short answer is that you are allowed to take photos on commercial flights. I'm not sure of any policies for different airlines, but the law is clear on the matter.
The safest way is to wait until you hear the "cabin crew to take-off position" or "cabin crew to landing position". With the cabin crew out if sight, no one can take your camera away. Usually the most spectacular pictures can be taken during this stage of the flight. When landing, you usually have larger window to take nice pictures because the plane descends relatively slowly compared to take-off. Make sure you choose a short exposure time of 1/1000 of a second or less by cranking up the ISO sufficiently. Under broad daylight conditions, the ISO could still be as low as 100. You can choose the F number around 6 or 7 for maximum sharpness. Then if you decide in advance that you are going to aim for landmarks at infinity just after take-off, the smart thing to do is to put the camera in manual focus and use some distant object to set the focus correctly (e.g. using the magnification in live view).
This is a picture I took just seconds after take-off from Longyear international airport.