White Paper 034 Addendum 53: Tests and Settings on a Panasonic AG-HPX371

Alan Roberts

Abstract

Data for this document is taken from a short examination of a production model of the Panasonic AGHPX371 camcorder (serial number #FOTEA0073), using the supplied lens (Fuji XT17x4.5). This is a HDTV camcorder, almost identical to the Panasonic HPX301. It has 3 ⅓" CMOS sensors, each 1920x1080. The manual makes no claims for noise levels. It records HDTV using the AVC-I or DVCProHD algorithm onto P2 flash cards (1080i, 1080psf, 720p), SDTV using any of the DVCPro50 or DVCPro or DV algorithms onto P2 cards (576i, 576psf, 576psfa). It can also shoot “off-speed” when recording 720p onto P2 cards, but only at spot speeds, it is not continuously variable as is the Varicam AJ-HDC27F. There are 2 P2 card slots.

Perhaps most significantly, the camera has electronic correction for chromatic aberration in the lens. Since cameras with ⅓" sensors suffer iris diffraction starting at about F/4, lens performance appears to deteriorate dramatically at F/5,6 and smaller apertures, this correction facility seems to eliminate much of the chromatic problems, leaving only the gradual softening as the lens is stopped down. Subjectively, this appears to move the onset of diffraction limiting by about 1 stop, and to make further stopping-down less objectionable. However, the lens must be on the list of known lenses in the menus for this to work. The camera is not sensitive to infra-red light.

The camera is light (5kg including lens), has a side lcd panel, and seems potentially aimed at the high-end consumer/professional market and full broadcast, which would normally demand interchangeable lenses. It has the useful Panasonic YGET luma metering facility, waveform monitoring, and a pre-recording facility (3 seconds for HDTV, 7 for SDTV).

It has the same range of external switches and controls as a full broadcast camcorder, plus internal menus for setting the performance, although not as complex as in the 720-line Varicam or the HPX2000/3000 range for example, but enough to control most of the important features. It has genlock and remote control but is no better suited to multi-camera operation than any other professional camcorder. It has two SDI video outputs (at HD or SD) and 1394 (Firewire), plus an analogue monitoring output. This puts the camera into the professional or broadcast market, subject to video performance.

The same assessment procedure was used as for other HD cameras, partly attempting to get a good “filmlook”, and the settings reflect that. It is useful to think of the camera, when used in this way, to be mimicking a film camera and telecine, with “best light” transfer to tape, with about 10 stops of tonal range. Assuming that a grading operation will be used in post-production, the settings attempt to give the colourist the same range of options as with film. The recommended settings allow about 1.3 stops of over-exposure (250%) and one of under-exposure relative to normal operation.

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