What's The Purpose Of The Video Camera Exposure Setting?

For your film to look skillful, you need to brand certain that it's not too brilliant (overexposed) or too nighttime (underexposed). The easy, lazy fashion to exercise this is to let the photographic camera work it out. But to shoot really adept video you need to set it yourself.

You lot can adjust the exposure by changing

how sensitive the photographic camera is to light (ISO)
the corporeality of calorie-free the lens lets through (aperture)
the amount of time the lite gets through (shutter speed)

If you make one of these bigger, yous tin can make one of the others smaller. So you could let twice as much low-cal in for half as much time.

Sensitivity (ISO)

The photographic camera'due south sensitivity to light is measured in ISO. Low ISO is around 100 or less, medium is around 200-400, high is over 400. If the ISO gets too loftier the paradigm quality volition go worse: it'll be less precipitous, with worse colours, and speckles of multicoloured 'racket'.

For skilful quality at high ISO, you need a camera with a big low-cal-capturing sensor. So most DSLRs and mirrorless cameras will shoot acceptable video at high ISO settings (800, 1600 or fifty-fifty college), just with compact cameras the quality speedily gets worse as y'all creepo up the ISO. You'll get the best quality filming at the camera'southbase ISO(you can usually find this out with an online search).

Aperture

You can also change how much light comes through the lens. Nigh cameras (only non smartphones) accept an iris which lets you adapt the size of the hole in the lens. The size of this hole is called the aperture, and it's measured in f-stops. An aperture of f/ii lets in twice as much lite as f/2.eight.

A wider aperture such as f/2 has less 'depth of field' than a smaller aperture such equally f/five.six (with the same lens). In other words, less of the scene volition be in focus in front end of and behind the subject area. High-sounding 'shallow focus' shots with blurred backgrounds can look not bad, just yous have to be actually careful to keep the main subject area abrupt. If the subject field is moving around a lot it's meliorate to employ a smaller discontinuity like f/v.6 to keep more than of the scene in focus.

Merely don't close the aperture down too far, particularly with a modest camera, as you lot'll lose sharpness because of an outcome called diffraction. Usually with a DSLR you desire to avoid apertures smaller than f/8 or f/11 depending on the lens.

Why does a bigger number mean a smaller pigsty?
Because f-stops are fractions: it'due south the diameter (width) of the iris, divided by the focal length of the lens. So if yous're using a 50mm lens, at f/2 the iris is 50mm divided past ii: 25mm.
Why do aperture numbers follow an odd sequence (1.four, ii, 2.8, four, 5.6 etc)?
An f-stop is based on the bore of the iris, but to halve the amount of lite it's the area of the hole that has to halve.

T-stops

Some cine lenses are marked in T-stops rather than F-stops. T-stops measure the amount of light that gets through the lens, not the size of the discontinuity. If you lot switch betwixt lenses at the same F/stop, the exposure might change because unlike amounts of calorie-free could exist absorbed or reflected by the lens drinking glass. But with T-stops, yous can switch between lenses with no modify in exposure.

Shutter speed

The third thing you can change is how long the sensor is exposed to the light. Shutter speeds are measured in fractions of a second. High shutter speeds (eg ane/1000 of a 2d) will freeze motion in the individual frames of your video, but the move may not look very smooth (see below).

Using discontinuity, shutter speed and sensitivity together

Yous can residual these three settings against each other. Say you've set the aperture at f/two with a shutter speed of 1/250, but you decide you need more than depth of field. You could terminate downwards the aperture to f/2.8 but use a slower shutter speed of ane/125. Y'all'd be letting in half every bit much low-cal for twice equally long, so the exposure would exist the aforementioned.

What'due south different about video…

This will all be familiar to experienced still photographers; but with video, there's a catch. To brand motility look shine, you need the shutter speed to be half the frame rate. (Yous don't need to worry most this if your scene doesn't include much motion.) If your video is 25 frames a second, the shutter speed should be 1/50th.This means that you have to exit shutter speed solitary, and modify just aperture and ISO sensitivity.

If you need to continue your aperture broad – e.thou. in vivid sunlight, or to go shallow focus furnishings – you can cut down the amount of light by using a special neutral density (ND) filter. Near pro video cameras have built-in ND filters, but for organization withal cameras y'all need to buy them separately. You can get them individually or in sets. Some SLR filmmakers utilize variable ND filters. These are expensive – and can give odd effects with wide-angle lenses – simply they let you lot smoothly alter the exposure without constantly swapping filters.

…and phones

Smartphones similar the iPhone have stock-still apertures. Considering their sensors are so tiny, they still have quit a lot of depth of field, even at f/1.7 or f/2. But having a fixed aperture ways that y'all tin just use shutter speed and ISO to vary the exposure. Most smartphones automatically choose the all-time combination, though you tin can select and vary them manually with the Filmic Pro camera app. And if you lot have a case with a thread for add-on lenses like the iOgrapher, you tin fit a variable ND filter.

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