Module 20

Updated: 03/29/2010

The Camera

Viewfinder

 We are gradually sneaking up on the operation of the total video camera. But, before we can really use one like a professional, there are a few more things we need to cover, starting with -- 

Viewfinder Types

The viewfinder of a camcorder can be a CRT, tube-type (like those used in the original TV sets), or a flat panel (LCD) display similar to those in laptop computers.

Some HDTV camcorders now use LCoS (liquid crystal on silicon) viewfinder displays instead of LCD. Precise focusing is critical in high-definition video and the sharper LCoS images aid in seeing focus problems.

Unlike studio cameras that typically use at least seven-inch displays, the viewfinders for camcorders must be much smaller. They typically use a miniature video screen viewed through a magnifying eyepiece.

Since camcorder viewfinder images are rather small for high-definition needs, various focus assist devices are available. One technique is the electronic magnification of a small area of the image that can be used to tweak camera focus.

Accommodating Left

And Right-Eyed People

With cameras that use side-mounted optical viewfinders, the viewfinder can often be flipped from one side of the camera to the other for operators who prefer to use their left or right eyes.

When the viewfinder is flipped in this way the image ends up being upside-down, unless a reversal switch is flipped. (This also explains why an image might inexplicably be upside down when you first look in a viewfinder.)

Holding your eye to one of these viewfinders for a long period of time can be quite fatiguing.

Cameras employing flat panel viewfinders (which you can view from a distance) can help. This type of viewfinder (pictured here) is also an aid in shooting at very low or high angles.

Flat panel viewfinders can also be used to compose shots that you, yourself, want to be in.  You can simply mount the camera on a tripod and (on many cameras) turn the viewfinder around so you can see it.

The main disadvantage of the flat panel display is that the images lose contrast and brightness when viewed in bright light.  This can make the camera hard to focus.

Once you get used to their operation, viewfinder goggles that resemble virtual reality goggles allow even greater flexibility. This type of viewfinder can be used to supplement a standard side-mounted viewfinder.

Since the viewfinder is connected to the camera by a long cable, you can easily hold the camera over your head, as shown here, place it flat on the ground, or even shoot backwards with the camera mounted on your shoulder.

For critical, professional work the best "viewfinder" is an external monitor, preferably, a bright, high-resolution color monitor. Even though this type of standalone monitor requires extra power and limits your mobility, it's the only accurate way of checking subtle lighting effects and critically evaluating things such as depth of field. 

Camera Safe Areas

Because of overscanning and other types of image loss between the camera and the home receiver, an area around the sides of the TV camera image is cut off.
 

To compensate for this, directors must assume that about ten percent of the viewfinder picture may not be visible on  home receivers.

This area (framed by the red lines in the photo) is referred to by various names including safe area and essential area.

Some directors confine all written material to an "even safer" area, the safe title area (the area inside the blue frame).

Although flat-panel TV displays don't inherently evidence overscanning as much as TV sets that use picture tubes, it's still a good idea not to include important information (such as writing) in the outer edges of the TV frame. ( ▲HDTV overscanning note.)

Shoot-and-Protect

As we noted in Module 9, HDTV/DTV uses the 16:9 aspect ratio shown above, and standard TV (SDTV) a narrower 4:3 aspect ratio.

Most producers are now shooting their shows in the 16:9 format. But, since a large percent of home viewers still have sets with 4:3 aspect ratios, productions need to be shot so they can be used in either format.

As we've previously noted, the term shoot-and-protect refers to shooting scenes in 16:9 while "protecting" the 4:3 area-making, sure that it still contains all the essential information. To do this a 4:3 grid (shown in red here) can be superimposed over the 16:9 viewfinder image.

Adjusting the Viewfinder Image

Viewfinders need to accurately represent the nature and quality of the video coming from the camera. Although flat screen viewfinders generally remain accurate, viewfinders that are based in miniature picture tubes (CRTs) can drift resulting in an inaccurate picture.

Because the image in a camera's viewfinder is actually the image from a miniature TV screen, it's subject to brightness and contrast variations. In addition, with tube-type viewfinders there may also be an electrical focus problem and the occasional lack of proper image centering.

Adjusting the viewfinder image does not affect the video coming from the camera itself; but adjustments to the camera video will affect the viewfinder image.

To make sure that the contrast and brightness of the viewfinder are set correctly, the camera's built-in, electronically generated color bars (if they are available in the camera you are using) can be switched on and checked in the viewfinder.

The viewfinder brightness and contrast controls can then be adjusted until a full, continuous   range of tones from pure white to solid black are visible.

If the camera doesn't have a built-in test pattern, the quality of the camera video should first be verified with the help of a test pattern and a reliable external video monitor before the viewfinder controls are adjusted.

Checking Viewfinder Accuracy

The next step is to check viewfinder alignment to see that the area shown exactly corresponds to what the camera is "seeing."  

Although flat panel viewfinders normally remain stable over time, the frame area accuracy of a tube-type (CRT) camera viewfinder can drift to a point of not accurately showing the output of the camera.

This is relatively easy to check.

First, a video monitor must be used that has itself been perfectly aligned with the help of a test pattern. The output of the camera in question is then hooked up to the monitor and the camera is focused on a test pattern so that the outermost edges of the test pattern just fill the viewfinder image.

Any discrepancy between the viewfinder image and the monitor image should be obvious. Viewfinder alignment may have to be adjusted with the help of an engineer or technician.

Occasionally the electrical focus will also drift out of adjustment on a tube-type viewfinder. This will make optical focusing difficult until it is corrected, generally with the help of a test pattern and an engineer. (Since there are very high voltages within CRT housings, these adjustments should be left to someone familiar with these matters.)

Wearing glasses while using a side-mounted CRT camera viewfinder can present problems -- especially in seeing all four corners of the image at the same time.

Therefore, many side-mounted eyepiece-type viewfinders have a control in the eyepiece to correct for variations in eyesight. This is referred to as diopter correction. If adjustable correction isn't built in, eyepieces can sometimes be purchased for the viewfinder that can eliminate the need for basic types of eyeglasses. 

Status Indicators-Viewfinder Variety

To help you keep track of everything you need to know while shooting, video camera manufacturers have added an array of status indicators to viewfinders. (And you thought only things like designer jeans were status indicators!)  

First, there are miniature colored lights around the edges of the video image. Red, yellow, and green are common colors. Sometimes they even blink to get your attention.

Next, are the indicators that are superimposed on the viewfinder video. Boxes, bars, and lines are common configurations.

Some of the viewfinder messages may be superimposed over the image in plain English (or the language of your choice). For example, "Tape remaining: 2 min."

Finally, some camcorders have small speakers built into the sides that announce (again, in the language of your choice) such things as "low battery," or "remaining recording time: five minutes."

Because every manufacturer uses a slightly different approach, you need to study the camera guide to determine what a camera is trying to tell you. The time spent becoming familiar with the meaning of these indicators will more than pay for itself in avoiding disappointments and failures.

Viewfinder status indicators can include the following:   

• a tally light indicating that the camera is recording or "on the air"
• a low battery warning
• minutes of tape remaining
• color or white balancing may be needed
• low light; insufficient exposure
• low-light boost (gain selector switch) circuit in operation
• indoor/outdoor filter in place
• zoom lens setting indicating how much further you can zoom in or out
• auto/manual iris status
• f-stop setting
• shutter speed setting 
• audio level meter
• remaining tape (or recording medium) time
• a zebra pattern for setting maximum video levels
• superimposed masks for the safe area and the 4:3 and 16:9 aspect ratios
• the presence of customized camera setup profiles to accommodate specific types of subject matter or desired image effects
• camera warm-up diagnostics

In the next module we'll take up camera prompters.