DV101

Last month in DV101, I examined the issue of infrared contamination. I discussed the problems of IR radiation with digital cameras, especially when light is severely attenuated with neutral density filters. A couple months ago I spent a day at CamTec Motion Picture Cameras with cinematographers Christopher Probst, Phil Holland and Jesse Brunt to test a number of infrared-cutting filters on both the RED EPIC and the ARRI Alexa. Last month I shared the results of tests with the RED EPIC; this month we’ll revisit that test and see how our filters worked on the Alexa.

Filters Tested

Let’s take a brief trip back to high school science class and revisit the electromagnetic spectrum. Sound waves, radio waves and gamma waves represent specific frequencies in the electromagnetic spectrum, the range of all frequencies of electromagnetic radiation. The spectrum includes wavelengths from 1 angstrom (one ten-billionth of a meter, or one-tenth of a nanometer) all the way up to AM radio at 100 meters in length and beyond.

Back in my day (yes, you can visualize me sitting in a rocking chair with a smoldering pipe in one hand and an afghan on my lap, peering out at you over the tops of half-moon spectacles, if you so wish) the light meter was a cinematographer’s best friend: a primary tool and an invaluable asset. Although there were exceptions—the late Douglas Slocombe, ASC, BSC, could famously call out the exposure based only on looking at the scene—they were extremely rare. Even the most experienced and revered cinematographers used a light meter to evaluate the exposure levels of their scenes.

When you mention smoke or fog, most people conjure up images of a misty, creepy cemetery at night, with fog crawling along the ground like the undead, or of black smoke billowing out the windows of a burning house. These are practical special effects, generally. Fog can be your friend, however, as it adds atmosphere to photography and defines light in a unique way.

Resolution is a term that is thrown around with reckless abandon like mashed potatoes at a food fight. Unfortunately, it’s a term that is rarely used properly.

The higher the number of samples taken, the more accurate the digital representation of the original subject.

I have always been a strong proponent of teaching and sharing, especially with aspiring filmmakers.

Today, with the prevalence of large single-sensor cameras, the number of lens options for the HD shooter has increased exponentially. Not every lens will work with every camera, however. In a previous DV101 column I discussed crop factors, utilizing lenses designed for larger target (sensor) areas on smaller targets, and the changes in apparent focal length/field of view.