I was pondering this subject after watching an excellent BBC documentary on Marianne North. You can find her wikipedia entry here...
She was a 19th century artist who travelled the world painting plant life, but in a way no one else had done before. The standard way of doing this back in those days was to paint a fairly static image on a clean white background. Efficient but a bit dull to non scientists. Marianne changed all this by painting her plants in context, in beautiful bold, vivd colours, with other plants and animals in the scene, while always maintaining the focus on her subject. She blurred the lines between documentation and art and in a way this is how I see good wedding photography.
The basic function of a wedding photographer is to capture the day. This has changed somewhat in style in recent years as back in the film days, shots were a lot more posed and there was very little reportage style photography. Film was expensive and you didn't have an unlimited supply. I remember my own wedding in photographic terms as a series of posed shots, there were no shots of the actual service and mostly it was just some group shots and a few posed couple shots. I can remember clearly how my jaw started hurting about half way through from the fixed, rictus like grin I produced whenever the photographer inevitably asked me to smile.
Today you are expected to capture every moment of the day, especially the key moments, the first kiss, the walk up and down the aisle, first dance, that sort of thing. Some people assume that all you need to do this is a fast camera, with a good burst mode and decent autofocus. Turn up, fire up the machine gun, I mean camera, and off you go. That is documenting a wedding, people will notice you, and their behaviour will change. They'll be looking around wondering who the hell invited the paparazzi, especially if you start using your flash to capture those startled rabbit like expressions as your victims look around in bewilderment. Then there is the other way, the reportage way, where you fade into the background and pick your moments. The guests become unaware that you are there and behave as they normally would. I really believe there is an art to this and you can see it in the work of any good reportage photographer. There is also the way they use light, they will instinctively position themselves to get the most out of any given situation. There is art in that and it takes practice to get better at it.
Then there is the use of artificial light. Some people will only ever use natural light, they even boast about it as if its some special ability. Well, in a way it is, using natural light well is a skill. However, using flash ( i.e. speedlights or strobes ) in the heat of a wedding day, using them well so that they blend into the natural light, that is an art as well and one I believe you need to master, even if mostly you prefer not to use that skillset. In the dance shot above, I used a strobe, and bounced the light off the ceiling to better illuminate the couple. But it doesn't look like a "flash shot" in my opinion.
There is further art in posing couples to look their best. This is stepping away from pure reportage photography, but its a skillset I think that is important and sets you apart from those who don't bother to learn it. Posing a couple quickly and efficiently to look their best is not easy, and is another skill I think we can point to when speaking of wedding photography as art.
So to summarise, I believe there are people out there who just document weddings, and people out there who document them and create art in doing so. I'm striving to be one of the latter camp, although there is a long way for me to go to match some of the greats in the genre ( but that won't stop me trying ).