Why would you want to show colors that aren’t there? Why do you want black and white diagonal lines going across your screen? Don’t worry, we’re about to go over those functions right now. [vm_ads:segment_break:1]
You shot your project and now you’re in post. You bring the image up on your computer. Uh oh. There is no detail in the whites! These areas are commonly referred to as “blown out” or “clipping.” You also notice it’s not quite as sharp as you thought it was. Of course, this was incredibly hard to see during the shoot on the tiny monitor or with the bigger monitor that had a huge glare or other objects and colors in the frame. But now, at your desk, with the color program open, your whites are blown out, your edges are soft, and there’s no great way to fix it. Well, next time you shoot, make sure you use exposure and focus assist tools to prevent these issues.
Before we talk about the exposure tools you can use, we need to talk about IRE. IRE is the acronym for Institute of Radio Engineers, and it effectively measures the luminance percentage of your video. A measurement of 0 is pure black with no detail and a measurement of 100 is pure white with no detail. Moving from 1 up to 99 represents varying shades of grey from near pure black to near pure white. This is a highly accurate way to measure exposure, and there are tools that use these values to help us confirm what we see with our eyes, including zebras, false color, waveform monitors and histograms. Let’s cover these one at a time. [vm_ads:segment_break:3]
If you’ve ever seen an LCD with those black and white diagonal lines going across your screen, those are known as zebras. These are warning signs to let you know which parts of your image are overexposed, or close to it. Zebras use the IRE values of your image and displays those banding black and white lines over the danger areas so that you may say, “Uh oh, there may be no detail there.” In that case, you can adjust your settings accordingly; change the lighting setup, change the f-stop, add neutral density and so on to make sure your exposure is perfect.
Some cameras have multiple settings for zebras. When I use my Panasonic HVX200A, there are three settings. The first only shows zebras in areas that measure over 100 IRE where the image is actually clipping. The second setting begins showing zebras at 95 IRE when the image is very close to clipping. The third setting displays zebras at 90 IRE when the brightest areas have detail but are still close to clipping. Although the second and third settings may show some areas that aren’t actually clipping, it is good to see how dangerously close they are. But wait, before you go trying to make sure your image is zebra-free, understand that not all clipping is bad clipping. [vm_ads:segment_break:4]
Blown out whites, soft edges – the next time you shoot, make sure you use exposure and focus assist tools to prevent these issues.
To Clip or Not to Clip
The dynamic range of video varies. Higher end cameras may have a wider range, but those too can lose detail in the whites depending on the set up. When lowering the exposure of the image, your darks become darker and your overall image may be underexposed. So make the choice. If you can’t control the lighting, then see if you really need detail in the whites. If there is a lit light bulb in the shot, fire, or clouds on a sunny day, you may lose some of that detail in the whites, but the image may still look absolutely beautiful. With lower consumer cameras, if you are clipping in certain areas, what you see is what you get. But, with the higher end cameras that shoot raw, you can bring back some detail in post. That detail can be recovered because it was never lost in camera, just on the viewing platform you were using at the time. [vm_ads:segment_break:5]
“So, I know the zebras can show me what’s absolute white, but what if I want to know what is absolute black?” Well, make the absolute blacks another color. “But absolute black is not another color, that’s false.” Exactly. False color assigns specific colors to specific tonal ranges to easily decipher your image. Let’s take the RED camera for example. With this video false color mode selected, the image becomes greyscale. The blacks at 0 IRE are represented as purple. IRE values of 1-3 are blue. 96-98 IRE is yellow, with orange representing 105-107. The 18% gray is green. The area you typically would want the brightness of Caucasian skin tones is pink.
Again, this is just a general barometer. There may be stylistic reasons as to why you would not want these colors to line up. If you’re shooting into the night sky or a scene lit by one candle, expect some purples and blue to show up. [vm_ads:segment_break:6]
A waveform monitor is another great tool that can help you judge your exposure properly. A waveform monitor shows a representation of your frame from left to right and shows you how dark or bright it is based on the IRE measurements. The shadows and darker portions of your shot should hover around the 0 line. Any underexposed areas of your shot that are below or compresssed along the 0 line will be black, without any detail. Highlights in your clip will hover around the 100 line and any overexposed areas will typically be compressed into the 100 line, or extend beyond it. Any areas in your shot beyond 100 will be represented as pure white, without any detail. The middle portion of the scope represents the mid-tones, ranging from black, to grey to white as the percentage increases. With a little practice, you’ll easily be able to utilize this to make sure any areas that are over or underexposed are intentional choices. [vm_ads:segment_break:7]
Remember the xy graphs from school? Well, you can also use one to preview your exposure with a histogram display. Many DSLR’s on the market today offer this as an overlay option on your LCD. The bottom row (x) represents the range from dark to light. The height of each part of that wave (y) represents the amount being exposed. If the left side height is dramatically larger than the right, you have a lot of darks in your shot. Conversely, if the right side is higher, you have more brights. The main occurrence you want to try to avoid is having the far left and/or far right measurements going off of the scale. This means you are losing that information. Your image is clipping. There are no details in the dark or no detail in the whites. Again, understand that in certain situations, you may not be able to avoid this. But the optimal situation is to have a nice balanced waveform without each end touching the edge. [vm_ads:segment_break:8]
Time to Focus
“Great, my shot is exposed properly, but my focus is off!” The screens on the DSLR cameras are often hard to judge focus on. Don’t worry, there are a couple of tricks to make sure your focus is right.
Focus magnify can be used for focus precision. You press the button and your camera zooms in digitally to an area you desire. Essentially it ‘magnifies’ an area of your image. You then adjust the focus and press the button again, zooming back out to your original framed image. To be clear, you are not touching the lense or manually zooming in at all. The feature works like putting a magnifying glass over the image and then taking it off after you are focused up. When you are in the magnify mode, use the arrows to navigate around the image.
Also, more and more digital cameras are including a focus peaking function. And if you follow the theme of what these functions are doing, you can probably guess what the focus peaking does. It highlights, using a very stark contrast, the part of the image that is in optimal focus. Activate the setting, choose your focus by adjusting the focus ring and watching as the highlighted area moves around the screen. When the highlighted or peaked area matches the part you want to focus, you're good to go. No more guessing focus.
Learning new functions or the technical parts of film and video can be intimidating at first, but if you want your stuff to look great, it’s a must. When you see a button or a function on your camera that you are unfamiliar with, don’t be afraid to look it up. The best way to get the image you are going for is to understand the technology and how it is processing to create that image. That way, you can manipulate it to your liking and get the image that you’ve had in your head onto the screen. Sometimes, what looks good to the eye or on a monitor isn’t exactly what you’re getting in the long run. That’s why it is so important to use whatever exposure and focus assist tools you have to make sure you don’t get any surprises in the edit room. [vm_ads:segment_break:9]
For optimal color grading, record your image as ‘flat’ as possible. This means shooting with low contrast and low saturation. The idea is that the contrast can always be increased and the saturation can be enhanced, but optimally not the other way around. This is generally done shooting with the Log C format. When shooting with this flat look, however, the preview image is very dull and to many, unattractive. To solve this issue, a LUT is applied to the monitor. This LUT acts as a stand in for the color correct and gives a curve so that the image is being previewed at a contrast and saturation level more comfortable to the eye. It alters the curve on the waveform monitor. It is important to remember that this LUT is only on the display and does not affect the original image.
JR Strickland is an award winning director, filmmaker and musician. He specializes in strong narrative storytelling.