The Red Epic and HDRx Part 1

One of the most exciting features of the new Red Epic is the HDRx function. High Dynamic Range shooting has been around in the stills world for a while. Generally it’s used for landscape shots, where a number of exposures are combined into a single frame. The end result is often quite surreal depending on how the image has been processed. On the Epic the HDRx function is not designed to give the same extreme HDR look as with stills, but more as additional highlight protection. For this two-part blog I went into S+O Media to play with the HDRx function of the Epic - I’ll be posting the results of that test next week, but for the time being here’s how it works.

For every frame the camera records, it immediately takes a second at a higher shutter speed. Both frames are recorded separately but contained within the same file. The normally exposed frame, or A-track, can then be combined with the underexposed X-track. For example, you might shoot a scene at 1/50^th of a second shutter or 180 degrees for you film people. If you then wanted to dial in three stops of highlight protection, the X-Track would be running with 400^th of a second, or 22.5 degree shutter. You can dial in up to six stops of highlight protection using HDRx, with the camera's natural latitude quoted as being 13.5 stops, the six additional stops should give you an incredible 19.5 stops of latitude.

The Arri Alexa does a slightly similar trick but built into the chip. Its Dual Gain Architecture means that the Alexa chip contains both high and low sensitivity pixels, allowing it’s high latitude.

Currently there’s a very simple system within RedCine-X, which is the free one-light grading software that Red supply. A slider controls the blend from the A-Track to the X-Track; you can dial in the amount of X-Track you want to include.

I personally don’t expect the camera to be used in HDRx mode all the time, and there are shutter artefacts which come from the use of HDRx, especially the stronger flavours. But in situations where you don’t have total control of the scene, or where you want the option of holding detail in difficult to control highlights, it’s an amazing tool and one that’s only just starting to be used. Burned out clouds in the background of your scene? Not any more! Switch on HDRx and you can dial in the whiteness.

My next blog will include a video example of HDRx on the Red Epic; where we put it to the ultimate test... A car interior shot with no lighting!

Benedict Spence has been working as a lighting cameraman for nine years and a director of photography for the past three. Ben will be dishing the dirt on his experiences with Red’s new Epic–M, on behalf of broadcast and crewing facilities company S+O Media.