[tig] Daddy's Boy (HDcam to 35mm 2.35)

Steve Shaw steve
Fri Nov 28 11:49:00 GMT 2003

A while ago I posted that we were showing a print in the UK last Monday that was generated from an HDcam shoot.

The screening went very well and the response from those in the audience who were from the industry were amazingly positive about the quality of the final anamorphic film print - yes, HDcam to anamorphic.

The following, should you be interested, is a rough outline of the process the project underwent.

Daddy's Boy is a 10 min short that attempted to use the concept of Digital Film capture as far as practically possible within today's constraints. 

It was shot on HD using Sony's CineAlta F900 HDcam camera with a non-prime Cannon zoom lens - a very basic setup.

The DoP, Alex Wakeford, followed instructions well on how to setup and use the camera resulting in high dynamic range images without crushed blacks or clipped highlights, ideal for the following DI process.

The approach adopted by the DoP was to not attempt to 'grade' in-camera (on set) but to capture as much dynamic range and detal as possible enabling decisions to be made in post, mimicking the standard 'film' procedure of OCN capturing a wide dynamic range with the grading and print processes producing the desired final image.

With this approach the DI process worked well with regard to the final image quality and colourimetery.

The original HD image data, obviously shot linear, was mapped into Log space during the DI/Colour correction process and displayed via a Log to Print LUT, mimicking the print curve charteristics of a traditional film process. This removed the main negative trait of video captured images, and combined with the fact that the image had been captured with high dynamic range/low contrast provided a final image mimicking the look and feel of film captured imagery combined with superb resolution, stability and cleanness provided by the use of a digital capture medium.

The fact that the final output was to 2:35 anamorphic and has been so well regarded for final quality shows what is possible with HDcam capture.

However, when shooting the sound engineer forced the production to shoot using time-of-day timecode rather than continious timecode. This caused problems when loading the image data into the offline (FCP) system and the subsequent online autoconform. This is not something the client will allow to happen again.

Note: A related problem found on another feature shot HD (Avanim - shot in Israel and also technically supportes by Digital Praxis) was the HD camera failing to pickup timecode correctly when recording continious timecode, which caused the offline system to abort loading as it saw a timecode break!

The biggest problem facing Daddy's Boy was the online autoconforming of the edl. The problem was that the edl was not 'clean' causing a lot of issues with the online conform, resulting in something like 50% of the short having to be manually eye-matched to the offline video. Not too bad with a 10 min short but a nightmare with a full feature.

The second major problem was again audio. Although the production had been instructed to shoot 24fps HD they opted to shoot 25fps, which necessitated a 25 to 24 audio speed and pitch change. This proved to be next to impossible due to the difficulty in accurately matching the two stereo channels during the audio processing. This resulted in audio phasing errors with the left and right channels alternately becoming advanced or delayed with respect to each other. In particular it was the re-pich that introduced the errors.

For dialogue it was decided to go with the non-pitch changed 24fps version, as the frequency change was not too noticible. However, when music was involved this was not an option as it was immediately obvious something was wrong.

The only way to rectify this was to use the original non-speed changed music and re-edit the online as the offline had been cut to beats in the music. The saving grace here was that the DI system (yes, iQ!) had full editorial capability enaling an easy re-edit without the need to go back to the offline.

The main negatives reported by the production team were associated with shooting, accepting the offline/online edl issues. They disliked the electronic fan noise produced by the camera when hot and found the camera back-focus slipped too easily, also due to excessive heat (the project was shot during a UK heatwave!).

The DI process itself was fairly painless, except for the edl issues, although getting the various film labs (two were used - one in Rome the other in the UK) to produce accurate film prints from the timed internegative proved to be something of a headache. That's chemicals for you!


Disclaimer: Digital Praxis is an independent operation that has many clients: some longterm, some short. Either way we aim to perform a service that has a positive impact on our client's operation and for which we get paid. A historical client list can be found on the company website and anything posted on the TIG (or elsewhere) should be read with this in mind - and with the incredulity usually associated with big fish stories and alien abductions.

Steve Shaw
Digital Praxis Ltd.
+44(0)7765 400 908
steve at digitalpraxis.net

More information about the Tig mailing list