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Camcorder Masterclass
Don Mouatt

Camcorder Masterclass - Index

Post-production Sound

Eric was a trifle unhappy about whether some of his location sound was good enough for the finished sound-track. We told him that whatever precautions are taken to maximise quality of the original sound, it was inevitable that some replacement or enhancement will be required if that element of a soundtrack is to be of a reasonable standard.

So what is a reasonable standard?

  1. There should be no unwanted noises. Whenever possible replace with suitable sounds from a sound effects (SFX) tape/disc or, from other video recordings (see 2).
    Replacement might be effected as each shot is laid or, as a continual run, using audio-dub over the whole sequence. It depends on the extent of the problem.
    There are occasions where replacement would also result in wanted sound being lost. For instance Simon and I filmed an interview as part of a documentary and carelessly failed to notice that the air-conditioning was on. Because we couldn't re-shoot this integral part of the documentary our only hope was to use a graphic equaliser when editing. This eliminated about 90 per cent of the unwanted noise and the sequence, although not perfect, was usable.

  2. Unless the situation demands otherwise - and there are many exceptions - the level and, probably the dominant content of the ambient sound should be consistent throughout a sequence. Because the necessary repositioning of the camcorder when shooting, and other factors, leads to fluctuations it often pays to use it solely to record a few minutes of uninterrupted ambient sound which can be dubbed in if required. Volume levels might be matched using a mixer or the sound replaced as in (1) above.

  3. Sound should not unnecessarily annoy an audience. Whilst it might be appropriate for a sequence involving, say an aircraft or perhaps a mighty waterfall, to commence with a moderately high volume, turn it down to an acceptable and less obtrusive level once the point has been made. The audience can then get back to enjoying the visuals, and perhaps listen to additional sounds.

  4. The overall volume should obviously vary according to what is being screened as well as take into consideration the presence of voice-over and music. In the latter instances SFX should come through but not too loudly. However, avoid having a completely silent portion of soundtrack, even if only a few seconds. Life isn't like that. There's always noise around, though our brain may elect to ignore it. In extremely quiet situations a low-key "buzz" track of the ambient sound is far more acceptable.

  5. Often perfectly recorded location sound needs enhancing. to induce atmosphere or suspense. A quiet country scene might benefit by discreetly adding the "caw" of crows or other relevant sounds. owls and creaks in a spooky night-time scene can add suspense. But unless those sounds are fundamental to the plot and/or pre-empt disclosure of their perpetrator, don't overdo it.

  6. Pre- empting adds realism. A car approaches; add the sound prior to the visual and carry it on for a few seconds after the vehicle has disappeared from the frame.

  7. Sound perspective is important. In the above car sequence the engine noise should increase as the car approaches and decrease as it goes away. Sometimes, such as in UK TV's Last of the Summer Wine, perspective is flouted. We see the three main characters in extreme long shot but their speech is very distinct. In this instance we accept, because it is within the context of the show and frequent usage of that device had made it a trademark. In other circumstances ignoring the advice could invite unintentional laughter.

  8. Sound jump-cuts should be avoided. This is particularly important when editing a sequence which requires unbroken sound, perhaps a band playing, or the aircraft mentioned earlier. Hopefully the camcorder operator will have kept recording as suggested at (2). If so, that sound can accompany the various shots forming the sequence, either via the audio-dub or the insert-edit facility.


Camcorder Masterclass - Index

Camerawork: Depth of field and Pulling Focus

Eric said, "On the box the other night I saw a very effective sequence where the top half of a girl (medium shot) was fully in focus whilst the background was out-of-focus. suddenly the focussing altered so that the girl was blurred and the background became clear. How was it done?"

What Eric had viewed was an example of pulling focus. It is easy to achieve but, before explaining how, it is necessary to know a little about depth of field because pulling focus involves its manipulation. Although a lens may be set to focus on a subject at a specific distance, there is a zone in front and behind which also appears to be sharply in focus. This zone is termed depth of field. The extent of the zone is variable and depends upon whether the camcorder's zoom lens is set at the wide-angle, telephoto, or somewhere in between , position (focal length); the distance of the subject, as set on the lens (focal distance) and finally, the aperture setting.

Unfortunately even with the most well featured camcorder it is not always possible to vary the aperture setting without seriously affecting picture quality. Therefore, unlike still photography manipulation of the depth of field rests principally on the first two factors.

A long focal length setting, i.e. at or near the telephoto end, combined with a close focal distance, gives a shallow depth of field. Even more so in poor light (wide aperture). Conversely at, or near, the wide angle and infinity settings the zone is much greater, especially in good lighting conditions.

It follows from the above that our two subjects must be located in different zones, each requiring it's own focal distance setting. Secondly, because a shallow depth of field is necessary, the zoom lens must be set around the telephoto end. This latter setting remains unchanged throughout the shot. Apart from placing the camcorder reasonably near to the subject (or at least the first one) and selecting a long focal length setting, two other conditions are required. Manual focussing is essential and the camcorder should be mounted on a tripod to ensure steadiness and an unaltered framing.

Practice makes perfect

Before recording, rehearse the framing and variable focussing. When satisfied, start shooting with the first subject clearly in focus, continue running for the desired length (after allowing about five seconds for any instabilities etc), and then smoothly manually refocus until the second subject clearly dominates. If misfocussing or jerky manipulation of the zoom lens occurs, then reshoot. As previously indicated do not readjust the zoom lens during this operation.

Pulling focus adds variety to camerawork, can assist a smooth transition from one scene to another or, as is frequently seen on TV, make a conversational sequence between two people look better by first focussing an the speaker, and when the listener responds making him or her the new centre of attraction.

Manipulating the depth of field is also useful when you want to avoid distraction of the subject by it's background. For example, a close-up of a rose usually looks better if the surrounding foliage is out-of-focus. In these instances the appropriate depth of field manipulation is selected but there is no pulling focus to bring the background or foliage clearly into view.

Finally, whilst manipulating the depth of field is an integral part of good camerawork, like other elements, there needs to be a valid reason. It shouldn't be overdone.


Camcorder Masterclass - Index

Post production Sound: Commercial Sound-effects (SFX)

We have discussed the constituent elements of a satisfactory SFX track elsewhere and suggested that, where replacement or enhancement of the location sound is required, the appropriate material might be found on SFX audio tapes or CDs. (Lists held by one major store suggest that most SFX are being marketed on CD only.) The SFX can be obtained from leading record shops and because the price includes copyright fee can be used without fear of illegal dubbing etc.

There are other producers but, to the best of our knowledge, the most comprehensive range in the UK is marketed by the BBC; their SFX covering a wide spectrum from babies crying to a pitched battle. If horror or Sci-fi is your thing, or you want some "Bubbling Musical" (it goes well with pictures of hot springs or bubbling mud etc.) then there's something for you as well.

Although at first sight there seems to be every conceivable SFX available, Sod's Law guarantees that the one you want either isn't there, or doesn't quite match requirements. This is where a little ingenuity and imagination comes in; you might opt to adapt or mix the sounds or, in the last resort, make your own. Before sighing in despair, there are at least three points worth bearing in mind when selecting a potential effect:

  • Don't disregard a commercially produced sound simply because its title doesn't precisely match your situation. Very often that sound will easily pass muster for something broadly, or possibly even loosely, akin. For instance, SFX relating to the departure - sea-wash at stern - engines running at 18 knots and then berthing of a cross channel ferry appear to be totally authentic when matched with the appropriate visuals of a cruise ship.

  • Don't be put off if the sound perspective fails to accord with the visuals. With judicial use of the audio-mixer volume control, matching can often be achieved. A hovering helicopter sound can be manipulated to represent the machine approaching, circling overhead and moving away. Similarly waves can be made to crash , at the appropriate moment, against rocks or that same sound to lap on shingle, simply by controlling the volume.

  • Various SFX can be mixed to obtain a more comprehensive sound scenario. Dull location sound for a beach scene can be enhanced by discreetly adding lapping waves, the occasional seagull and children at play. Properly blended and timed to fit the visuals such additions can make a world of difference. A word of warning - don't overdo the gulls - it can aggravate an audience and sound amateurish (using the derogatory sense of that word).

If you need to make your own sounds it can be quite good fun. Experiment. The opening and closing of an umbrella, held near to a microphone, or rustling the right kind of paper can simulate a bird flapping its wings. The sound of a fountain, steam hissing etc. can be imitated orally or by using a hose. Even the hum of a refrigerator motor can prove useful on occasions. There are various methods of creating an integrated SFX track, much depending upon the equipment available and, to a large degree, personal choice. The key element is don't try and do too many things at a time. However, we will have to defer covering these aspects to another Masterclass.


This article first appeared on IAC Online in August 2001