For a relatively small investment a professional photographer can capture the moment with the best equipment and experience to know how to get the best backgrounds etc.
Photos last a lifetime, and you only get a fleeting moment to get them.
Don’t risk it. Employ a professional. There are many out there advertising their services. You will want to figure out what you want first, and then discuss it with a few photographers. There are still some photographers who do not put any prices onto their websites or public display. Why not!!!!?????
However don’t just go on price alone as well. You may well be able to get a person who will only charge a small amount for 4 hours of work. I would seriously question they capability to deliver. So stick with someone you can meet and have a look at their work. Most will happily discuss a range of prices for your needs. For example if you only want a photographer for the ceremony that will probably be a lot cheaper than having two professionals for the whole day.
Talk to your celebrant about whom they might recommend.
Above all get a professional – PHOTOS LAST A LIFETIME, THE MOMENTS IN A CEREMONY ARE FLEETING.