Sound Devices, with the assistance of Fletcher Chicago, performed complete, instrumented audio tests on Sony's HDW-F900 HD Video camera. This testing was performed in response to inquiries from Sound Devices customers concerning interconnect and set-up with the F900 camera. Audio performance of several other popular (some now discontinued) Sony video cameras is included for comparison. This test data reveals how to set your mixer for best interconnection, as well as how well the camera performs as an audio recorder.
Getting the best performance from an audio mixer requires knowing the performance of all elements in the signal chain. Audio quality is only as good as the weakest link. Are these HD cameras audio circuits the weak link?
The F900 camera, which retails for $103,000 USD, is showing up on features, high-end corporate-industrials, commercial spots, and broadcast. The F900 is from a long heritage of Sony broadcast video cameras, and shares much of its analog audio circuitry with early generation cameras. While these video cameras are generally derided for their audio performance, the F900 is a capable performer. Armed with the information below, the audio engineer can draw their own conclusions whether SOP (sound-on-picture) with the F900 is usable and how to interconnect properly.
To our knowledge, this is the only complete (well...nearly) set of audio test data taken from the F900 camera. The camera documentation is essentially useless for determining interconnection, clip points, and gain structure.
Two things are certain, many productions expect to see SOP tracks, and others want dual-system audio. Hopefully, the information below will clarify that decision.
The cameras tested came from Fletcher's production inventory. They are well maintained and representative of the condition that one hopes to encounter in the field. These weren't beat up mules.Analog audio signals were generated from an Audio Precision (tm) test instrument (System Two, Dual-Domain 2322) and input into the camera's audio inputs. The F900 records audio signals as digital audio data through its A/D converters. For several of the tests the camera rolled tape. The tape was played back on a compatible video deck whose audio was output as AES/EBU audio data into the Audio Precision for measurement. This method removes many variables, and is the path that most production tracks take. Once in digital, production tracks usually remain in digital up to release.Several analog tests were performed on the camera itself, including tests of the monitor circuit, and line level output. These signals, while essential during production, won't show up in post (fortunately!).Testing camera audio is a laborious, tedious task. No wonder the camera manufacturers don't include complete specifications! Testing just the F900 took an entire day. Sound Devices wishes to thank Fletcher Chicago for providing the cameras, decks, location and assistance.
Quick, Subjective Evaluation
Well...the F900 audio performance (measured from analog input to the digital recording) is good to very good through the line inputs. In fact, it is better than most analog audio recorders, including well calibrated analog Nagras. That alone means a great deal to many. Also, its performance surpasses a Beta SP camera by a wide margin. For a wide range of applications including dialog, music recording, and loud sound effects, the on-board audio is very usable - especially when hit with line level signals with good control of maximum level (limiters, limiters, limiters!). It doesn't outperform professional DAT recorders or dedicated digital film-sound recorders, but the convenience of usable SOP is a major benefit.
Unfortunately, a couple areas to avoid are the microphone preamps and the monitor return path. With a self-noise of 16 dB, the microphone inputs are clean only with hot signals. In addition, you won't know if the audio went down to tape properly, because the monitor return path is abysmal. At least in post it will sound good.
On big budget shoots with dual-system recording, using the camera tracks as back-up is very handy.
The monstrous chart and graphs below show the actual values of the audio measurements performed on the F900. As mentioned, measurements of three other Sony cameras are presented for comparison. Sound Devices will continue to perform tests on cameras if time and availability cooperate. This information is invaluable for location sound engineers.
The charts following are the expressed copyright of Sound Devices. No unauthorized commercial used is allowed. If you would like to reprint the numerical or the AP charts, please contact Sound Devices directly. The graphs are available in full resolution EPS form without watermark, if required.