Oh ok I see. Would the H4N (on its own) suffice for decent indoor audio, for the time it takes me to save up for the cardioid condenser mic that alcove recommended (few months)?
For the indoor cardoid condenser mic, would you still use this on a boom? Doesn't it have to be extremely close to the person speaking?
Okay, let's consolidate the info on the thread for all of the audio newbs...
DSLR audio is crap at best. You will need a separate audio recording system.
The optimum separate audio system would be a digital audio recorder, a mixer and a selection of wired and wireless mics with the obligatory accessories - boom, shock-mount, cables, cases, extra data cards, batteries, etc.
Most indie filmmakers cheap out on sound, so they go with one or two mics and a digital audio recorder; currently the H4n ($299) is the cheapest that will accept XLR inputs and record higher bit/sample rates. Many professional sound types have one in their kit as an emergency third back-up or keep one handy when they're out and about to capture that neat sound to add to their library; but "the pros use it" was all the marketing people needed to hear and that sold it to the ultra-low budget market -
that does not make it a professional piece of gear.
You need the proper tools to do specific jobs. A shotgun mic is a good selection for outdoor usage, it has (or should have) terrific off axis rejection - meaning that, in principle, it picks up the sound directly in the front of the mic and rejects sound from the side and back although that is not in actual practice 100% true. A shotgun mic is a poor choice for indoor usage as the way it picks up sound gives the dialog that "roomy" "hollow" "echoey" sound which makes the dialog less intelligible and is almost impossible to mitigate in audio post. The choice for indoors is a hyper-cardioid condenser mic which will lessen the "roomy" "hollow" "echoey" sound but not eliminate it. You can further reduce the roomy sound by properly treating the set with sound blankets and carpeting. And yes, you always use a boom; proper boom technique is another discussion.
A mixer is essential for proper production sound recording; it allows for on-the-fly adjustment of sound levels, usually has much better mic pres, limiters & metering than stand-alone recorders, and will allow for better mix & monitoring distribution.
Syncing sound is simple - use a slate on the set and verbally announce the take. You line up the audio SMACK with the visual; it's been done that way since the inception of sound for picture back in the late 1920's. If you are using video it's even easier - you can line up the wave shapes from the camera and the audio recorder. Keep detailed video and audio logs.
A professional sound cart can cost $50k and more; hell, a single mic that most pros would use costs more than most indie types spend on their entire sound kit! However, all the best gear in the world won't do you any good if you cannot operate it properly and use correct mic/booming/mixing technique. As with all disciplines this takes knowledge and experience to acquire. Your best bet is to work with someone who knows about sound. If you are dead set on DIY you may be better off renting what you need.
Also, Alcove, since you've mentioned that the H4n is not your favorite, which ones might you recommend that are at least close to the same price range?
There is nothing else in that price range which is why it's so popular, it's relatively dirt cheap. In the under $1k range I really like the Fostex FR2-LE ($600) with the Oade Brothers mod (about $300) - better mic pres and they eliminated the hiss from the heaphone monitoring. The Edirol R-44 ($1k) with the Oade mods ($450?) and the Tascam HD-P2 ($750) also with the Oade mods ($350) are quite popular as well, as is the Marantz PMD-671 ($1k) (I hear that Oade may do mods for this as well). The Oade mods put them at a little over $1k, but nothing competes until you get to the $2k+ range like the Sound Devices 702, etc.