Although AE modes are pretty useful for the novice, and well worth experimenting with, you can do a lot more using careful adjustment of shutter and exposure. Not every camcorder has this level of control, however.
A camcorder's auto-exposure system can be fooled by mixed lighting conditions, with a particular culprit being bright sunlight with lots of shadows. When such uneven lighting causes high contrast between areas, shadows may end up being completely dark and lacking in detail. You can bring shadowed areas back out by artificially overexposing the brighter areas a little, so the subject matter becomes visible. Although it's also possible to do this with editing software, for example with Adobe's excellent Shadow/Highlight filter, you can't resuscitate what your camcorder didn't pick up in the first place, and the results won't look so natural.
Looking at the image above, on the left we see the results with the exposure left on automatic, but on the right we've increased exposure to bring out the shadowed areas.
It should also be noted that camcorders usually offer video gain as well, which simply increases the intensity of the electrical signal and doesn't directly alter the shutter aperture. This can be very effective in low light, as Canon's HV20 shows. But it won't have the effects on depth of field that opening the aperture has.
Manual Shutter Speed
As with digital still cameras, a camcorder also has a shutter speed, and it can be different from the 25 frames / 50 fields per second used by the PAL video format itself. Setting a higher value than 1/50th has the same benefit as a fast shutter speed does for a stills camera -moving objects will be less blurred. This is how the Sports AE mode described earlier works. For the same reasons, increasing the shutter also has the same drawback that less light is captured, so the video will look darker. Exposure may need to be boosted to compensate, assuming your camcorder allows you to vary the two separately. However, you can't set the shutter speed lower than 1/50th without causing a stuttering slow-motion effect, as one shutter exposure will be spread across multiple fields and frames. Some camcorders don't even support lower shutter settings except when in still image mode.
Looking at the image above, on the left the standard shutter speed has caused a blurring of the image, but on the right shooting at 1/1000th makes the moving objects much sharper.
So there you have it - some of the obscure settings hidden in your camcorder's menu explained. In future weeks, we will return to other advanced camcorder techniques. So keep checking out TrustedReviews' camcorder section.
Beyond AE - Manual Control