This is the correct answer.Do it.Turn up in a black poloneck and beret, chain smoking with a cigarette holder, then proceed to ignore all the people and instead take a dozen out of focus close-ups of leaves, bark, cutlery, and door hinges, and if engaged in conversation immediately start waffling about heroine.
We had a few friends taking pics at our wedding. One was just setting up as a pro and did a 1 hour session doing the 'official' group photos and a few of the two of us. That was their gift to us, they offered rather than us asking. Another was also a pro and was the partner of a friend. We didn't ask them to, but they took lots of nice casual pics. I think being a partner meant they were probably happy to have something to do rather than the the socialising thing. A third friend, a hobbyist, did a session where we set up a blackboard and few funny hats so people could write a message and pose for a fun photo. This was a great way to get group photos of people who aren't in the official group pics and are great fun to look back on.
In your position I'd be happy to do it but discuss with them what their expectations are. I wouldn't expect you to spend the whole day behind the camera. Probably a few of the ceremony, a few group shots (not every possible combination) and a few candid ones during the evening.
I did it this past weekend for friends who had a registry ceremony and a reception at a local village hall, but it was definitely more on the "will you bring your camera and take some photos" end rather than "will you be the official photographer", and both sides were happy with that - the bride and groom didn't want endless posed photographs and I didn't want the responsibility. I also quite frankly don't have the gear or expertise - I shot everything with a cheap SLR (Canon 500d), kit lens (18-55) and a flash with diffuser. I know I'd have got better results using natural lighting but I don't have an f1.4 lens and I can't afford to buy one.
I took so many photos that there are bound to be a few reasonable ones. I haven't even looked through them all to be honest - I looked through the pics from the ceremony and posted a few online to give people something to look at then bunged the lot on a memory stick and gave it to the bride and groom so that they can choose the best and edit them where appropriate (I did shoot raw 🙂 )
As an aside, we had a pro at our wedding who we paid a huge sum, the film didn't capture the colours of the dresses - brown not green, the composition was poor and exposure off due to bad processing. We have a box of those pictures in the loft, and a nice casual B&W photo in a frame from my step father on the mantelpiece. Endless posed photos don't capture a wedding.
I used to shoot about 5/6 films of B&W and hope to get 36 in a really nice album as a present. I've shot about 10 weddings for family and friends. Always informal and always stated upfront so it is understood. I've then had to order multiple albums for the bride and groom's relatives because they like the informality.
If they are precious about photos of the wedding, don't do it. If they are more laid back, or really have no other options, I'd say why not?
Do it (probably)! Give me a shout on Facebook if you want some advice, I do two or three a year.
Do it maybe. I did, was a hectic stressful day, but I loved it.
Bride and groom loved the photos and I was really happy how they turned out. I even managed to make the bride cry when a couple weeks later they were just expecting files turned up with an album of my favourite pics in.. She still regularly gets it out to show anyone and everyone.
So if you're confident in your own ability so it, they obviously are otherwise they wouldn't ask. I managed to scope out the venue before hand and did some mock photos beforehand so prepared as best I could.
Oh and it gave me an excuse to buy some additional camera kit..
