November 2007

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Anyone familiar with photography knows about f-stops. Calculated as Focal Length divided by Diameter (of the front lens element). The smaller the value of the f-stop, the more light passes the lens, the shorter exposure time necessary, the narrower the depth of field, the lower ASA/ISO rating necessary.

Typical f-stop values are f/1.4, f/2, f/2.8, f/4, f/5.6, f/8, f/11, f/16, f/22 and f/32, but there are lenses with f-stops as low as 1 and as high as 128. With the arrival of automatic exoposure meters, fractional f-stops have also become the norm.

T-Stop

When you start using professional film lenses, you will come across the phrase T-stop. While the f-stop is a mathematically derived value, the T-stop is a calibrated value. Since lenses have optical elements, and each of these elements blocks a (tiny) amount of light, the actual amount of light coming through a lens is always lower than the f-stop value suggests.

Therefore most cine lenses are individually calibrated to give the actual amount of light transmitted, the T-stop (T standing for Transmission.) T-stops are always (slightly) higher than f-stops.

Despite all marketing and hype around HD, good old Standard Definition is still remarkably strong, as a recent survey by SCRI shows:

[...] recording formats are always a bell weather of trends in our industry. This year we see expected large penetration for SD format, but surprisingly no HD formats reached more than HDV (25.5%), despite the fact that HDV is a relatively new player in the market. HDCAM still has over 21% penetration, with DVCPRO HD slightly lower at about 17%. Neither reached the remaining penetration of Betacam SP (well over 50% of the market still has Betacam SP). Penetration of HDCAM has remained essentially constant since the last Survey. In SD products DV based recorders (DV, DVCPRO, DV CAM, and variants) are present in more than 80% of all facilities.

Which fits into our experience here in our production company. We do get hired by some bigger names, such as BBC, MTV or ABC, along with national and regional TV. We also do a bit of industrial films. And not once did we have a request for HD.

The market is just not yet ready for it, to pay a premium for a quality that most viewers will not see.

That said, it will be interesting once true HD TV-sets become standard in the households, and parallel cameras such as the RED One make it possible to deliver HD content without extra costs.

Here’s some camcorder marketing talk you can ignore:

1. 100x digital zoom — digital zoom enlarges your digital image, resulting in lower quality.
2. Software included — chose the software that suits you, not some feature-limited, outdated software that comes bundled with your camera.
3. Filming at 0 lux — no camera can film without light. The result is a grainy, colorless, low quality picture.
4. Electronic stabilizer — while promising sturdy pictures without a tripod, this really degrades your picture quality. Optical stabilization is what you want. Or – for best quality – a tripod.
5. Digital effects — this is really something you want to do in editing, not in-camera. Keep your options open!

If you have a Mac and a video camera, there is a nifty tool called iDive (“the iPhoto of video”). Good program if you want to organize your shots, it integrates into Final Cut Pro or iMovie, lets you keep compressed versions of the footage. And it gets good to very good ratings across the range.

When I lived in the US, my host family had a pool table in the basement. There we would play from time to time, and I thought I was good when I managed to get two balls into a pocket with one shot. Boy, was I wrong:Her e is another cool trick.

Usually all you can do to get smoother pictures out of a moving vehicle, is to run the camera at a higher speed and lower the tire pressure. (Well, the bigger budget solution is of course to hire a low loader.) Bose, known for great audio gear, also make suspensions for cars. Seeing their video, I wonder when the first grip rental places will get a car equipped with one of those:

For extra credit, here’s a french clip: