Follow Focus and Remote Control
If you're accustomed to working in the video world with autofocus-assisted cameras and their deeper depth of field, optics operation on the RED will be a big change. Focusing on the RED is completely manual, as it is on all professional film cameras. Manual focus means total creative control, but it also presents the challenge of keeping the image you want to see in focus. A lens is pretty difficult to manually operate, which is why all professional lenses have geared teeth along their diameters (Figure 4.17) to enable the attachment of manual and motorized follow-focus kits and whips. In this section, we'll start with the simplest, least expensive types and work upward.
Figure 4.17 A close-up of the gears on a 35mm prime lens.
The basic follow-focus kit consists of a gear that connects to the lens and a set of interconnecting hardware to control everything with a focus wheel. I use an ARRI FF4 double-sided follow-focus kit (about $3,000) with a 19mm rod adapter (about $500). It's nice and lightweight while offering precise control for most lenses. Sometimes it's not comfortable or physically possible to focus from directly alongside the camera—say, from a dolly or fast-moving handheld shot. Adding a nice flexible focus whip like the ARRI 13.5-inch can help alleviate this limitation. A focus whip is a mechanical cable that connects to the focus gears of a lens, allowing you to operate it from a distance (usually a couple of feet).
Figure 4.18 The Keson 50-foot fiberglass tape measure is perfect for measuring focus.
Sometimes even a focus whip doesn't have sufficient physical reach to permit focusing, such as when the camera is mounted on a remote head high up on a crane. It's difficult to get anywhere near the lens to focus. For those situations, you need a remote focus (Figure 4.19). These can be wired or wireless, with the wireless usually being more expensive. The pros use gear such as the Preston FI+Z wireless system (www.prestoncinema.com), which can go for upward of $14,000 depending on the options you pick, but is worth every penny (Rodney Charters, ASC, uses these on 24). C-Motion (www.cmotion.eu) offers an even more elegant and sophisticated wireless system called the C3 for higher-end budgets.
Figure 4.19 The Preston FI+Z remote wireless follow-focus controller.
Moving down a few dollars but retaining plenty of functionality and quality is the Bartech (www.bartechengineering.com) BFD wireless focus unit for about $2,100. Bartech also offers wired units that are even cheaper. ARRI offers a simple wired remote follow-focus system. Whether you decide to include a remote focus system or not, you'll definitely want at least a regular mechanical follow-focus system to pull focus properly with cinema style lenses on the RED.