Photo by Visuallens
Jeff Ascough has been a professional wedding photographer in the United Kingdom since 1989. He has covered over 1000 weddings with a documentary photography style. Ascough emphasizes capturing the moment without any prompting or interference and using available light. American Photo voted Ascough as one of the ten best wedding photographers in the world.
Advice for wedding photographers
The best thing to do is to practice with a model. Take images in different lighting conditions and see which give you the best images. That's how I started out. You should be looking for how the light molds the subject. Sometimes it's best to squint when looking at the light as this gives you a better indication of the light direction.
One of the differences that separates the talented pros from the rest in photography, is the photographer's ability to see light direction and quality. Try to second-guess what is going to happen. It might sound weird, but I have almost a sixth sense when it comes to photographing. I can see the image in my mind's eye before it happens. I suspect this is a result of many years of experience, though, rather than any special ability.
I know how and when to position myself for an image even before I bring the camera up to my eye. Once I'm looking through the view finder, I refine the framing and decide on what to leave in and what to leave out of the image. I then wait for the desired moment to happen. If all hell is breaking loose around me, e.g., the dancing at the reception, I'll go with my instincts and react to things happening. This manner of photographing is more haphazard though, and my success rate is a lot lower.
It's important to be as unobtrusive while photographing weddings. That said, you can be unobtrusive while less than three feet from the subject. It's all about how you behave when photographing. If you permanently have a camera up to your eye, firing off hundreds of images, the client is going to be very aware of you. Also, hiding in the shadows can be more intrusive than standing close to your subject, because odd behavior is noticeable. If you simply have the camera down at your side and just quietly observe, they will relax and start to ignore you.
Unobtrusiveness doesn't mean you can't be seen. That's a mistake many people make. For many clients, unobtrusiveness means that you are letting them get on with their special day without making them stop for photographs.