Why do I often see lav mics used on indoor interviews? I can understand outdoors, or if the subject it far away. But why do I see a person wearing a lav in an indoor setting in what presumably is a couple of feet away from the camera? I would think that a shotgun would pick-up the sound just as well and you would not have to see the lav in the shot. (Though with effort I know a Lav can be hidden). Are shotguns usually relegated only to high quality scratch audio? BTW, I think this phenomenon is more prevalent in corporate videos.
There are two general methods to employ a shotgun mic: on a boom with a dedicated operator, or on camera.
A properly-operated boom mic is great but requires expertise and is easy to get in frame, or introduce handling noise. This in turn requires communication between camera operator, boom operator and sound technician. This can interfere with the spontaneous nature of an interview.
Also in a tight space the boom requires additional floor area and complicates positioning multiple cameras and lights.
To avoid inhibiting the subject, it's often best to have the cameras back, not in their face. However the boom must be closer which negates this somewhat.
A camera-mounted shotgun is not an audio telescope -- the main strength of any shotgun is off-axis rejection, not on-axis pickup. If camera mounted, you can't effectively position the shotgun to null off-axis noise. Shotguns also have a rear pickup lobe, so noise behind the camera can interfere.
With the camera pulled back to allow more natural subject expression, it usually produces worse quality sound than a lav. It's more prone to picking up room echo and unwanted sounds, vs the lav which picks up direct sound from the subject.
Maybe because there is zero time for setup? I use a hypercardiod on a standard microphone stand with boom arm for sit-down interviews. Sometimes I add a lav as a backup. If it's a walk-and-talk or standing interview and I can't use a boom pole I use a lav.
If you mean an on-camera shotgun, for me that's an absolute last ditch measure as simply a slight improvement over the in-camera mics - even at 2 feet away.
A general rule: the further the mic is from the subject, the more room sound you get, no matter what microphone you use.
The better acoustic treatment the room has, the further you can have the mic without ill effects such as a 'boxy" sound.
The character of the sound also changes depending on how far the mic is from the subject.
If the budget allows for it, use both. We often have a mic boom operator with a wireless sennheiser on the pole in addition to a high quality lavalier on the talent. The close to mouth pickup the lav provides is great, clean audio, and the boom with a good mic (we use Rode NTG1 or DPA mics) provides another channel of audio if something goes wrong. Plus, it is sometimes desirable to have a bit of ambient sound from the boom mic mixed in with the lav audio. On camera mics often pick up the mechanics of the camera (motors, fans, etc.).
Hands down, use a LAV. It's not really a hassle at all. The subject will sound clear as oppose to using shotgun. It also cuts down on room noise big time. You might always still get a little noise but it's WAY easier to correct in post then a really poorly mic'd talent. I literally just had to go through this recently because our LAV had issues and resorted to an off camera mic positioned close to a stationary subject. It was the worst.
I disagree with several of the above comments. Dialogue audio recorded on a lav mic is not better than a good quality shotgun mic (that is on a boom hanging as close as possible to the talent). Typical lav placement puts it on the talent's chest and it's tone, therefore, contains much more base and less of the natural tone of the voice. Also, hanging a shotgun from a boom (I use a C-stand/holder instead of a boom op for static talent) is much less obtrusive for the talent. Yes it's hanging near their face, but you don't have to make them uncomfortable playing with their clothing either ("It's okay mam, I'm a trained audio professional"). Not to mention the problems that arise when the talent is talking and they touch their clothing producing fabric noise.
That being said, there are great uses for lav mics and I use them all the time. If it is a run-and-gun shoot with no room for the boom or the talent is moving and you don't have a boom operator or if there is significant environment noise that a very directional shotgun mic can't isolate out. As was mentioned, using both is the safest way to insure you get solid location audio.
Unless the area is *very* noisy or close booming is not possible, my hypercardioid (AT 4053b) sounds better in every way than my best lav (Countryman B3 into a Sennheiser G2 wireless). I always use the hyper except in cases where it's just not feasible.
Sorry, I just saw the post from dgwvideo above - he's right - my comments are redundant.
One more perspective: I've always used the "belt and suspenders" approach to recording audio in the field - and in the studio too. By that I mean, if I'm shooting an interview - a sit-down or walk-and-talk - or even a dramatic scene with actors, I mic them with lavs (wireless usually) but I also record with a boom mic (shotgun usually). This way I get to choose the best audio which can change depending on the circumstances as others have pointed out here. If someone hits their chest or if they are wearing silk shirt or something like that you may get a thump or some rustle on the lav as Jarrod points out. Alternatively, the shotgun position needs to be managed too if the interviewee or the mic "shifts" in direction or axis. Also, the possibility of recording the "room" refection (ambient) is typically greater when using a boom mic - though this is not necessarily a bad thing. Of course, a good soundman monitoring the quality and recording as it's laid down is the one indispensable necessity. But still, my two-cents, "belt-and-suspenders" is the way to go if you can. Just like in life.
...hanging a shotgun from a boom (I use a C-stand/holder instead of a boom op for static talent) is much less obtrusive for the talent....
This may be the case for studio production of a scripted narrative, but it's not my experience in documentary field production. This is especially when interview subjects are shy, inhibited or in emotional turmoil.
It is true the lav must be plumbed through their apparel but they quickly forget. This is proved by how easy it is for a subject to depart the set wearing an expensive Sennheiser SK100 G3
By contrast a boom-operated shotgun mic in the subject's field of view reinforces in their mind they're being interviewed, and they clam up. In a studio you can mitigate this a little by using a stand, but in the field that's often not an option. That's why you don't usually see field news crews using a shotgun on a C-stand.
However the OP asked about indoor shooting, and assumed the presence of a lav meant a shotgun wasn't employed. Often that is not the case -- there may be a shotgun out of frame, and the lav is for backup or additional coverage. This is especially needed for a multi-person interview where the shotgun must flip back and forth.
In general the sound from a properly operated shotgun is better but it's also easier to make mistakes, get boom in frame, introduce handling noise, interpose an obstacle to a roving camera in a tight space, etc. Even if caught it can break the take, and if that happens when the subject is about to open up, that's a big loss.
Your point is well made, but I guess we'll just have to agree to disagree. I use a shotgun mic on interviews (in the field) all the time and when subjects are nervous it's usually because of the camera/lights rather than the mic. It's nice for them to be able to just walk in and sit down so the conversation can start without having to wire them up first.
I think we've probably exhausted the pros and cons of each style of mic at this point. The main thing is to use what works best for your production/workflow. There really is no right or wrong answer.