You know what they say — dynamic range doesn’t grow on trees. Well maybe they don’t say that. But it is true. It doesn’t. If it did, we’d all be great cinematographers. So if it doesn’t grow on trees, what is it and how can I get more of it? Great question. Read on.
Dynamic range refers to the range of which a camera can successfully capture the lightest and darkest areas of an image without losing detail. Once this range is exceeded, the highlights will wash out to white and the darks will turn to black blobs. So the higher the dynamic range, the better!
Often dynamic range is confused with latitude. Latitude is related to dynamic range, but is not the same thing! Latitude refers to the exposure flexibility of your captured image — so how much you can alter it in post to attain the correct exposure. Latitude is dependent upon dynamic range. While dynamic range refers to a camera, latitude refers to the image it captures.
How to increase dynamic range:
Since dynamic range is a capability of your camera, the best way to attain high dynamic range is to buy a camera with high dynamic range. For example, the high end digital video cameras made by RED and ARRI fall under this category. The new Blackmagic Cinema Camera also has high dynamic range. This video from the good folks at OneRiver Media compares the dynamic range capabilities of the Blackmagic Cinema Camera with that of the Canon 5D Mark III DSLR. It’s a perfect way to visualize exactly what dynamic range is, and the limitations of any camera in terms of attaining the correct exposure. Let’s watch:
But as we all know, one thing they do say is that money doesn’t grow on trees. So if you can’t fork over the dough for a snazzy camera, consider the following options for increasing dynamic range:
Using the camera you have, making conscious decisions about in-camera image settings can help to give your footage more latitude. As a general rule, turning down contrast and similar settings will help to retain more information in your image. For example, if you were to turn up contrast very high, you run the risk of losing detail in your blacks. Once that contrast is baked in to the image, it’s impossible to recover that detail in post. Alternately, if you turn contrast down, you’ll have a flat, boring image, but all of that information will be retained, and you’ll have more flexibility to tweak the contrast in post. That’s why very “flat” picture styles such as Cinestyle from Technicolor, or Cine from Marvel have been developed. If my explanation is falling flat, watch this video from Luka for more details:
If you have an iPhone, you may be familiar with HDR. It stands for high dynamic range. When taking an HDR photo on your iPhone, it works by compositing two images, taken one right after another. One image will properly expose the highlights, while the other image will properly expose the dark areas. When composited together, you get the best of both worlds in an image where both are properly exposed! Using an image editing program like Photoshop, you can do the same thing on your own, and can use more than two images. This same process is used in timelapse videos, since they are made of photographs. You may be familiar with the popular HDR Skies video? Just as the title suggests, the beautiful skies and scenic foregrounds are able to coalesce in picturesque harmony due to HDR:
In video, HDR works a little bit differently. The fact that you must roll video continuously, and that it’s not physically possible to attain identical framing from two cameras at the same time without a fancy setup are both initial barriers that must be overcome.
Magic Lantern has developed a pretty neat firmware update for some Canon DSLRs, which alternates shooting between two different ISOs between frames. You then merge the two exposures using their software.
You can also create multiple exposures of the same video file and fuse them together in post. Check out this tutorial video in which Jochem D uses Adobe AfterEffects CS4 and Photomatix Pro to do just that.
Graduated Neutral Density Filters
Last but not least, a more “old school” but just as effective trick is to use a graduated neutral density filter. To brush up on your neutral density knowledge, head on over to this Video School lesson. Unlike a regular ND filter, a graduated ND filter blocks out a varied range of light across its surface. One of these babies can come in handy when shooting a landscape scene. If you place the filter so that it blocks out more light at the top than the bottom, the effect is essentially as if you were shooting at a higher aperture at the top than the bottom, so that the brighter sky and the darker landscape are both properly exposed.
So what have we learned today? That dynamic range doesn’t grow on trees, yes. But I hope you’ve also learned ways in which you can increase your camera’s dynamic range and the latitude of your footage.