Professional camera controls – white balance, gain, shutter and Knee

In “Cameras – An Inside Look” we discussed the lens and all of the lens functions.  For this post, we will start to get into some of the main image controls of a professional camera including the white balance, gain, shutter and Auto Knee controls.

On the left side of the camera you will see a series of switches that give you control over some of the cameras most important functions.

On the panel there are controls for  “Save,” “Gain,” “Color Bars/Auto Knee,” and “W/B Preset – A – B.” Let’s begin with the “Save” control.

Save

If your camera has a tape transport or an optical disc drive, turning the save function on puts the camera into a “standby” mode.  This means that when the record system is not in use it will “spin down” the mechanism in the transport, thus saving battery life.  This is helpful if you have a long day with limited battery supply, however it is important to note that it will take a bit longer to power up the tape transport or optical drive before being able to record.  Keep this in mind if you are out shooting breaking news or sports where you need to rely on quick record functions in order to capture something quickly.  If your camera does not have a tape transport or optical drive (like a P2 camera) then the “save” function will merely power down your LCD monitor.  In general, setting the “save” function to the “on” mode will eliminate any unnecessary devices from powering on which will SAVE power to your camera.

Gain

A brief description of video gain is that it amplifies the signal being captured by the CCD or CMOS sensor.  As you add more gain it increases overall exposure to the scene.  This is not the most effective way of “lighting” your image, however.  Introducing gain into the image also creates noise.  You may notice this as little dots all around the image.  This is usually most visible in the black areas of the image.  Gain is measured in dB and it ranges from -3 all the way to +18 and above, depending on the camera.  It is generally recommended to never go higher than +6 db for an acceptable image but I like to stay at 0 db and just add lighting as needed.  Most people can get away with going higher without a noticeable difference but if you can, the least amount of gain the better.  On most professional cameras there is a “H,” “M,” and “L” switch for high, medium and low settings.  Generally these will be set to -3 db, 0 db and +3 respectivly – but you can set these in the camera’s internal menu settings to your liking.  I usually change my “H” setting to +6 db just in case I’m stuck in the dark somewhere and need the extra bit of punch.  Again, the less gain in your image the better.

Color Bars – Auto Knee

The next switch in line is the Color Bars – Auto Knee switch.  There are three settings here – Color bars on, Color bars off Auto Knee off, and Color Bars off Auto Knee on.  Obviously, color bars on turns on the camera’s internal color bar generator.  You would use this to set up your monitor and/or record bars to tape or disc for use in calibrating two or more cameras in post.  The second and third switch control turning the Auto Knee off or on.  The Auto Knee function of the camera (sometimes referred to DCC or dynamic contrast control) helps to control the contrast range in a scene.  Without getting into too much detail for this post (I will be writing about the Auto Knee of the camera soon enough!) I will explain it like this:  if you are shooting a subject against a brightly lit background like a window, you would turn the Auto Knee function on in order to bring out more of the detail in the over exposed area.  If you are shooting under normal conditions, you don’t necessarily need to have the Auto Knee function on and you would be able to dial the proper Knee setting using the internal menus.  Some Directors of Photography prefer setting the knee themselves and in order to do this you would have to turn the Auto Knee function off.  I will definitely go into more detail on this subject later.

White Balance Preset – A – B

Last but certainly not least is the white balance settings.  This switch gives you control over preset white balance and two individual white balance settings that you can store.  The first switch puts the camera in a preset condition.  On some cameras with dual filter wheels – the preset white balance is determined by changing the secondary color correction filter wheel.

On cameras with one filter wheel – for neutral density only, not color correction – the preset white balance can be set using a button that toggles between 3200 K or 5600 , or by pushing up on the AWB switch at the front of the camera – see the image below in the next section.

Preset white balance is either 3200K for indoor or 5600K for outdoor.  Therefore, it is ideal to always set your white balance and store it into either of the two settings (A or B) for more control over the color of your image.

Shutter, AWB and ABB Controls

Moving over to the front of the camera we can see three more switches.  Actually two switches and a button.  These can obviously vary from camera to camera but this is mostly the set-up that is common:

On the left is the record button.  This starts and stops the camera’s recorder.  This is similar to the one that is on the lens grip however it is more useful when shooting on a tripod.

Shutter

The shutter for the camera does a few interesting things.  If you’re new to photography or videography, this might be something difficult to understand right off the bat.  Don’t sweat it though, I will soon be getting into the basics of proper exposure.  The shutter helps control how motion is recorded.  A faster shutter will produce much more crisper edges when recording fast moving objects, like an auto race.  A slower shutter will give an almost strobe-like or dreamy feel to your video.   To activate the shutter, you need to move the protective cover away from the switch (a fail safe so you don’t engage it by accident) and push the switch up.  From there you would continue to push the switch up to change the amount of shutter.  These range from 1/15th of a second all the way up to 1/2000th of a second and above.

AWB Automatic White balance / ABB Automatic Black balance

The last switch on the front of the camera controls the setting of your white and black balance for the camera.  Black balance only needs to be set occasionally. Usually this is when you use the camera for the first time or if the camera has been sitting for a long time.  Also, it’s a good idea to set the black balance is there has been a significant change in temperature.  Rule of thumb here – set the black balance in the morning and forget about it until the next day.  To set the black balance just push the switch downward and wait for the camera to do the rest.  White balance the camera whenever you change lighting conditions.  To do this you would expose the camera properly on a white card and push up on the AWB button.  That’s automatic white balance because the camera is automatically going to set the white balance for you – not to be confused with “Auto White Balance.”   Never set the camera into an Auto White Balance setting because there is a tendency for the camera to shift colors while shooting.  This might be confusing but just remember that “Auto anything” is usually bad.

One last thing

These functions are used to control your exposure, color and overall image look.  For the most part you would operate your camera with most of these settings off.  When you add things like gain or shutter to your camera – the camera has a way of telling you that things are not “normal.”  Usually it will add something to the graphic overlay in the viewfinder, like an “S” for shutter or “G” for gain (depending on the camera) or it will light up an exclaimation point (!) in the camera’s view finder.  This is actually what most professional cameras do to indicate that something has been added to the image (like gain or shutter) so that you know something is going on. This is a great feature and will really help you from time to time.  Check the camera’s manual to understand what each of the indicators means and how it will effect your final image.