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Exposure intro
three ways to set the exposure
Bend and stretch


by Christina Fox

We have to be able to control the amount of light that passes through the lens and goes into the camera. If there is too much light the picture is said to be over exposed - too little light and it will be under exposed.

We can control the amount of light coming through the lens by the use of an IRIS or APERTURE. This works in the same way as the iris (or pupil) of your eye: when you are in bright light the iris is made as small as possible (it 'stops down') to prevent too much light entering your eye, when you are in a darkened room your iris becomes as wide as possible ('opens up') to let in as much light as possible. Of course your brain does all this for you and is constantly adjusting your iris depending upon the prevailing light levels. Domestic and professional cameras allow you to operate the camera iris in manual or in automatic. However, professional users tend to operate in manual only, using the auto iris only to do an occasional 'spot check'.

The AUTO EXPOSURE works by looking at the whole scene, averaging out the bright areas and dark areas and setting the exposure for this average. The problems start when something bright or dark comes into frame. e.g. If a white car drives across the frame the average light level of the scene will go up. The camera over compensates by stopping down the iris causing the whole picture to be under exposed. If a black car now drives past the average light level will go down and the iris will open up. Now the whole scene will be over exposed.

There are a selection of apertures to choose from when the camera is in manual exposure mode. Apertures are referred to as f-stops (or sometimes just "stops") - the smallest aperture is f16 which lets the least amount of light into the camera. The largest aperture is f1.6 which allows the maximum amount of light into the camera. The aperture sizes (f stops) available are:

BRIGHTER PICTURES <<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>> DARKER PICTURES


Largest aperture <<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>Smallest aperture


  1. Set the IRIS SELECTOR SWITCH (on the zoom servo) down to "M"
  2. Turn the iris ring on the lens to adjust picture brightness.


If you are unsure if you have exposed the camera correctly –

  1. Press and hold down the AUTO IRIS BUTTON beside the IRIS SELECTOR SWITCH.
  2. This will put the lens into auto iris while the button is depressed.
  3. Once the camera has adjusted the exposure take your finger off the button.
  4. If you don't agree with the cameras setting – make your own slight adjustment.


  1. Set the IRIS SELECTOR SWITCH down to "A"
  2. The camera will do the rest.

If you intend to work in auto iris you also have the AUTO IRIS MODE SWITCH available.

  • BACK L – use when the subject has a bright background behind them
  • STD – normal standard conditions
  • SPOT L – use when the subject is under a spotlight i.e. more brightly lit than the background

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When shooting in low light conditions (e.g. at night or in a poorly lit room) the iris will be fully OPEN at f1.7 but, the camera may still needs more light to produce a picture. In this type of situation you will find the GAIN helpful.

The GAIN is an electronic method of increasing the brightness of your picture. There are three gain levels to chose from:

DARKER PICTURES<<< 0 dB    +3 dB    +6 dB    +9 dB    +12 dB    +15 dB    +18 dB >>> BRIGHTER PICTURES

0dB of Gain    9dB of gain added   18dB of gain added

(If you want to see this image across the full range of gain see our Gain page)

DECREASED PICTURE NOISE <<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>INCREASED PICTURE NOISE

It is possible to alter these preset gain levels by entering the advanced menu settings.

As you dial in more and more gain you will notice that the picture becomes grainy (or noisy) and picture quality deteriorates.

If you are working in extremely low light conditions the HYPER GAIN button will increase the gain by around 40dB. The HYPER GAIN switch is positioned in the bottom left hand corner under the side panel cover.

Once the HYPER GAIN is switched on - the L M and H gain selector is disabled. Which is just as well - 40dBs is a lot of gain and a lot of noise in the picture.

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It is possible to adjust areas of the picture electronically to improve picture output…

The contrast ratio of most video cameras is now in the region of 50:1 i.e. the camera can accurately show two objects one light one dark (in the same shot) as long as the difference difference in brightness is no greater than a ratio of 50:1. However the camera can improves this ratio and reduces the possibility of for example, silhouettes,


  1. BARS – This setting displays the colour bars
  2. CAM/DL – Camera output with DynaLatitude. If the background is bright and overexposed compared to the foreground, the DynaLatitude will help to increase detail in the bright areas.
  3. CAM/DCC – Camera output and Dynamic Contrast Control. Prevents colour faults when shooting high intensity subjects.

In reality I found it difficult to see what the DynaLatitude was really doing. It certainly didn't seem to improve the shot on the monitor I had connected to the camera. Perhaps you'll have better luck.

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Zebra patterning is an aid to getting the exposure right. There are two zebra patterns available with this camera Zebra 1 (Appears in the viewfinder as the familiar diagonal zebra stripes) and Zebra 2 (appears as polkadots).

The Zebra ON/OFF switch is situated on the side panel of the camera body.

When switched on

  • A red light will light up the switch
  • Zebra patterning will appear in the picture highlights.

It is usual to operate with Zebras at around 90 or 95%.



  1. Start with the camera switched off.
  2. Press the MENU DIAL in – at the same time switch the camera on.
  3. Turn the MENU DIAL until page 4 appears
  4. Press the MENU DIAL in to select
  5. Turn the MENU DIAL until the arrow appears beside the message ZEBRA 1
  6. Press the MENU DIAL in to select.
  7. Turn the MENU DIAL until the level is set (around 90%) for ZEBRA 1
  8. Press the MENU DIAL in to set level

Finally arrow down to EXIT MENU option at the bottom of the screen. Press the Menu dial to exit.

Zebra - Page 4 MENU set to:

  • Option 1 = zebra set to the value you have selected in the menu (between 70% and 90%). Most camerawomen/men operate the zebras between 90 and 95%
  • Option 2 = factory zebra setting at 100%
  • Option 1 / 2 = displays 1 and 2 together in the viewfinder.

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Christina Fox