I regularly video interview comic artists and writers who are behind tables at comic and anime conventions. They are in large, open rooms with loud, packed chattering crowds, so lots of ambient noise. I am always behind the camera with the interviewee(s) in front. The camera (and mic) is usually pointed at the guest(s), but I often scan over their wares on the table.
I've had terrible audio quality--in terms of interpreting/hearing speakers over crowd--in the past and am just getting around to fixing it. I do not want to mic-up the guests as the interviews last 6-15 minutes and are usually performed within 2-5 minutes of meeting the guest and I'm off shortly afterwards. So handing a mic to someone, even if it's a wireless dedicated audio recorder lavallier seems a bit formal, but maybe I just have misconceptions about that. It seems like I would also need one for myself as well, though this wouldn't be as much of a hassle.
Given this, I've been shopping for camcorders to improve the video and audio. Specifically, it seems like it would be a good idea to get a camcorder with a zoom mic which has a super-parabolic recording area, which would be me and the guest right in front of me. Would a mid-range ($300-$600) camcorder with a built-in zoom mic be sufficient for this, specifically one has facial recognition to adjust audio properties to speech? I would also be fine with getting an external boom or shotgun mic for the camcorder, but I'm not sure if this would be necessary or if it would sufficiently reduce crowd noise.
A couple side notes, I have no idea if camcorders by default disable the front-mounted internal mic when an external mic is plugged in or if you can choose to leave it on. Further, I don't know if zoom mics are standard, in other words, I don't know if my junky Samsung SMX-F50BN camcorder has a zoom mic or just a generic single mic.
I've also tried to use some multi-speaker isolation algorithms about which I read in a few research papers, but could never get the MATLAB plug-in to give good results.
Any advice would be appreciated as to what I should be focusing on to best improve audio.