Videomaker – Learn video production and editing, camera reviews › Forums › Cameras and Camcorders › Professional Camcorders › deciding between xf100, AC90 and Mark III for first low budget feature › Recording sound separately
Recording sound separately has always been the recommended method. A scratch track can be sent to your camera(s) for helping to sync things in post. I don't think any of the cameras you're considering support time code input so you'll have to use an old fashioned clapper slte. Sound can be synced in post using a tool such as Plural Eyes which seems to be the tool of choice these days for doing this.
I don't want to scare you but you could be looking at around $500/day for a pro sound person. Can you get him/her cheaper? Absolutely. Craig's List and Mandy are full of people looking for a pro sound person who is willing to work for around $100/day. The problem is that you get what you pay for and this is often is someone who thinks they know what they're doing. The sad reality is that they don't and your sound track will suffer for it. A pro sound mixer has anywhere from $50K to $100K invested in their gear and, more importantly, knows what tools to use and when and how to use them to get the best sound possible. Gear rental is around $250/day and the sound op is another $250/day (typically for a 10 hr. day). If you live near a major city, see if you have a pro sound shop such as Trew Audio or Pro Sound as they will be able to help you find a good person for the job. The other site to check out is JW Soundgroup at http://jwsoundgroup.net/ This is a forum for pro sound mixers and they have a sub forum called "Work Available – Available for Work". Don't go here unless you're serious as these are pro sound people who can be somewhat sarcastic if you're not willing to pay a decent rate. As I said, most of them have a lot of money invested and don't take kindly to people not willing to pay them what they're worth.
Good luck with your project.