High Definition – When?
by:
Cal Barton
High definition wish inevitably become a widespread if not universal television broadcast format. However, it’s not yet clean once
that wish happen. So it’s likewise not yet clean once
high definition camcorders wish be habitually
required for acquisition for non-fiction programmes. With that in mind, this E-zine aims to give several background to high definition technology and the Sony high definition camcorders presently
available.
High Definition – Formats and Camcorders
Before venturing into the earth of high definition, it should be same
that our UK-based clients primarily use Digital Betacam and DV Cam camcorders and we find least demand for HD Cam. Our American clients are victimisation HD Cam much oft-times than our British clients but Beta-SP remains the format they most unremarkably request.
Two High Definition Formats
To begin with, the futurity of high definition broadcasting is unclear. There are two HD formats being considered for transmission. One is 720p (720 horizontal lines or rows of pixels in the image) and the else is 1080i (1080 horizontal lines or rows of pixels in the image). The “p” stands for progressive scan and the “i” stands for latticelike scan but much on this later. Panasonic manufactures the camcorders that generate 720 horizontal lines and Sony manufactures the camcorders that generate 1080 horizontal lines. The European Broadcasting Union (EBU) has recommended for discussion victimisation 720p for public service broadcasters but say that makes not mean they favour 720p as the standard HD format for transmission. Trade magazines say BSkyB plans to broadcast several 720p and 1080i in a service that wish begin once in 2006 though I was recently told 1080i may be the only format they use for transmission.
The Sony 1080-line system has one clean advantage over Panasonic’s 720-line system. Each images contains much than two million pixels (1920 vertical lines x 1080 horizontal lines) compared to 900,000 pixels (1280 vertical lines x 720 horizontal lines) in an images from a Panasonic high definition camcorder. This gives a superior picture. The advantage of the 720-line system is it takes less transmission information measure
to broadcast.
Now to the difference between “interlaced” and “progressive” scan. These terms refer to the way television images are processed for transmission.
Interlaced Scan
Standard definition television broadcast signals are processed by television sets in an “interlaced scan” format. This means the screen 1st scans the odd numbered horizontal images lines, or rows of pixels, consecutive
from top to bottom (1, 3, 5, etc). It then returns to the top and scans the even as numbered lines (2, 4, 6, etc). In summary, the full image from top to bottom is 1st ready-made with half the information there and half of it missing. Then the missing information is filled in. In the PAL standard, each of these two processes takes 1/50th of a second so the entire process takes 1/25th of a second.
Progressive Scan
“Progressive” scan differs from latticelike scan in that the images is displayed on a screen by scanning each line (or row of pixels) in a sequent order rather than an alternate order, as is done with latticelike scan. In else words, in progressive scan, the images lines are scanned in numerical order (1,2,3) down the screen from top to bottom, instead of in an alternate order (lines or rows 1,3,5, etc... followed by lines or rows 2,4,6). By increasingly scanning the images onto a screen every Twenty-fifth of a second rather than "interlacing" alternate lines every Fiftieth of a second, a smoother, much detailed, images can be make on the screen that is utterly
suited for viewing fine details and is likewise less susceptible to interlace flicker.
The Sony range of camcorders offer several latticelike and progressive scan functions in a range of settings.
Procam Television and High Definition Camcorders
As a facilities company, we are moving into the HD Cam market – but cautiously. We have Sony models but have not purchased any Panasonic products. This is only in response to what our clients have requested most. Below is a summary of each model and what it offers from the lowest to the highest priced model.
Sony HVR-Z1P
This is one high definition tv camera
we can recommend victimisation directly without exception. We purchased 15 of them in Feb of this year. It is an upgrade of the DSR-PD170P compact camcorder. The main reason for the unqualified recommendation is that the camera has a 16:9 chip so it shoots true wide screen images. It likewise delivers superior pictures.
Sony HDW-730S High Definition tv camera
The 730S is engaged towards thought
television programming rather than film or high end television drama productions. It shoots victimisation the latticelike function only and can be switched between 50i and 59.94i. Progressive scan is not possible with the 730S. But if you don’t need to use progressive scan and you’re shooting for television, this tv camera
produces superior
images and it allows you to shoot HD Cam on close to a standard definition budget.
Sony HDW-750P High Definition Tv camera
The HDW-750P offers the select of shooting 25 frames per second in progressive scan mode (25P) to give your images a film look or of shooting 50 fields per second latticelike (50i) to change
to the PAL broadcasting standard. The tv camera
has a 2.2 million-pixel FIT CCD, which is a step up from the IT CCD in the 730S, and Advanced Digital Signal Process
(ADSP).
Sony HDW-F900 Multi-format Cine Alta High Definition tv camera
This is the top of Sony’s high definition (1080 lines x 1920 pixels) tv camera
range. The F900 offers the ability to shoot in any setting you strength
want. In progressive scan, it can shoot 23.98, 24, 25, 29.94 or 30 frames per second. In interlaced, it can shoot 50, 59.94 or 60Hz. This means you can shoot for any standard anyplace
in the world. If you are shooting for cinema release, the F900 is the only Sony tv camera
that can shoot 24P (24 frames per second film standard).
Panasonic AJ-HDC27
The Panasonic range includes the AJ-HDC27 VariCam. This is a DVCPRO HD tv camera
that offers variable frame rates which can be set from 4-fps to 60-fps in single frame increments at the touch of a button. The question we have just about Panasonic high definition camcorders is makes going from the 625 lines offered by current PAL standard definition cameras to the 720 lines offered by Panasonic’s high definition format actually merit the investment required in acquisition and post creation equipment? It’s thing
to consider.
Thank you for reading this and please visit our web site www.procamtv.com to find out how we can meet you creation kit and crewing needs.
About The Author
Cal Barton began working in television for the Canadian Broadcasting Corporation in Vancouver in 1982. His background includes guiding coverage of major international news stories, guiding documentaries and guiding and vision combination for multi-camera shoots.
cal@procamtv.com
This article was announce on August 14, 2005