White Paper 034 Addendum 1a: Tests on Sony HDCAM, HDW900/3

Alan Roberts

Abstract

Data for this section relevant to the modified version of the SonyHDW900 camera, with hardware and software revisions issued in 2003, andreferred to as HDW900/3. It is little changed from the earlier version,but the changes have significance in that some settings for theoriginal camera nmo longer do what they should.

This model developed from the earlier HDW700, which was a 1035-linecamcorder, operating at 59.94 or 60Hz, interlaced. The later models are1080-line and will also operate at various frame rates from 23.976 to30Hz progressive, and 50 to 60Hz interlaced. They record a maximum datarate of about 144Mb/s onto Betacam-like tape, the transport speedvaries with frame rate so tape duration depends on frame rate.

The camera is based on the familiar form of the Beta camcorder and isused mostly for portable, single-camera work. It has many internalmenus for setting the performance, such that it can then be usedwithout external controls. It is not ideally suited to multi-cameraoperation, although it can be controlled remotely.

The menu settings result from several measurement and usage sessions,mostly attempting to get a good ""film-look"", and the settings reflectthat. It is useful to think of the camera, when used in this way, to bemimicing a film camera and neg-scan telecine, with ""best light""transfer to tape. It is always assumed that a grading operation shouldbe used in post-production, the settings give the colourist the samerange of options as with film. The laboratory tests were made using aBTS LDK9000 as a reference camera, of the type used in the Eureka1250-line system. The values for Gamma, Black Gamma and Knee allownearly 3 stops of over-exposure and one of under-exposure relative tonormal operation, although the knee has two points of inflexion whichcould conceivably cause colour contouring (although this has not beenobserved in practice). This setup approaches a film-look, provided thatDetail correction is either off or set to a low level. Images aregenerally sharper than even for 35mm film, this can be an issue forproduction, but can generally be dealt with by using filters or somepost-production softening. For use in Sport or Light Entertainment, itwould probably be beneficial to switch off the Black Gamma, and toincrease Detail Level to zero (factory setting).

Many of the menu items have little or no effect on image quality. Thosethat do so are highlighted. The full set of menu items is given forcompleteness.

One major new feature of the camera is custom-generated gamma curves,whereby the user can define a transfer characteristic and download itto the camera on a memory stick. An editor is available from Sony, toprepare the data, users should refer to Sony for more information onthis.

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