DVL-Digest 710 - Postings: Index DV for broadcast?? lenses Lenses (Plumbicon) Resources for information on the DV transfer protocol Shooting in Automobiles DV for broadcast?? - nospam-adamwilt@flash.net > BTW, there is no 1394 NLE that utilizes a 4:2:2 DV algorithm and > until that exists there probably will not be any DVCPRO50 machines > with 1394. And until there is a DV50 product with 1394 I/O, no one will build a DV50-native NLE with cheap and simple 1394 connevtivity. The codecs are there, as are the 1394 interfaces, but no NLE vendor is going to tie the two together unless there's something to connect to. Chicken and egg! > and generally speaking the problem is already solved by using SDI > or SDTI as the interface. At much greater expense and complexity. Which is one reason why DV25, and specifically DV and DVCAM, are outpacing both D-7 and the DV50 products in "system" applications where the benefits of native-format transfer and storage are important. It *is* possible to get those benefits over SDTI but the delay in rollout of compatible standards and the comparative pain of implementation (extra-cost option cards and few NLEs with SDTI connections) have diminished DV50's chances in the marketplace. Sad. Cheers, Adam Wilt lenses - "Perry" Bruce posted: >>...DID PLUMBICON TUBES REALLY GIVE SUPERIOR COLOR?< Well, it was a lot better than whatever was stuffed into the BVP- 300, which was a sister camera to the -330. So, in my experience, yes.< Whoa now Bruce, you're on dangerous ground here! The 300 used pure Plumbicons, the 330 used diode gun versions which gave improved resolution but a few side effects. At the time a lot of folk thought the 300 gave nicer pictures if you could put up with the softness. The 250 was identical to the 300 but with Saticon tubes. Interesting story behind the BVP-300 - it started life as a ThomsonCSF camera born in their sponsoring of CBS labs. Thomson had no means to manufacture it so they got Sony to make it (it was called The MicroCam) as a 2 piece unit. Part of the deal was Sony could use the design for their own version and that became the '300. Sony then redesigned most of the circuits to create the '330. I see that Philips actually have a site : http://www.plumbicon.com/ Where they say they have stopped making tubes and they are selling up all existing stock, so if you want some you'd better be quick! But then at: http://www.bbsnet.com/philips/Philips.htm they say they will carry on making them for 'many years to come'! Perry Mitchell Video Facilities http://www.perrybits.co.uk/ Lenses (Plumbicon) - Perry Mitchell Plumbicons (compared to the best CCD) were noisy, low sensitivity and not very sharp. They needed regular registration and suffered from beam pulling and focus problems. They also suffered inadequate red response although that improved in later versions. Most important they were a Philips monopoly and cost a fortune! Hitachi made Saticon alternates (and Sony licenced the technology) but they always suffered from lag. All of them consumed lots of power due to the magnetic deflection and focus requirements. Sony were on the point of releasing a Stat-stat tube with 100% electrostatic when CCDs arrived. Now those Image Orthicons . . . . Resources for information on the DV transfer protocol - Adam Wilt > Can anyone recommend some good resources for information on the DV > transfer protocol (data transmission). I'm interested in how error > correction is handled and information packets are sent and received > over the physical layer either independently and/or within 1394... Roger Jennings has some papers on the 'net: http://www.adaptec.com/technology/standards/1394formats.html http://www.adaptec.com/technology/standards/1394formats1.html The official spec is IEC 61883, available from http://www.iec.ch/ The 1394 Trade Association at http://www.1394ta.org has a lot of ancillary specs: http://www.1394ta.org/Technology/Specifications/specifications.htm, mostly covering AV/C control and communications. > Also manufacturers often stray from the original protocol in it's > interpretation of it; are manufacturers adhering to the original protocol or > does anyone find them creating their own proprietary version of DV... Most send the basic DV datastream around OK, but they vary in their interpretation of the command sets, the religiosity with which they adhere to the fine details of the protocols, and the extent to which they implement plug registers and the CMP. I don't think that ANY properly handle a multi-node 1394 network -- at least, none I've found do. Panasonic, however, have modified some of the header data in the DV datastream, making D-7 subtly incompatible with DV/DVCAM/Digital8 datastreams. For the most part DV NLEs happily accept and process D-7 data, but many do not set those specific bits, so that processed data are unacceptable to a D-7 deck. See Jan's earlier emails regarding the NLEs that ARE D-7-aware and handle this task properly. Shooting in Automobiles - "Perry" Jeremy Lanni posted: >I am looking for information about shooting in and around stationary and moving automobiles. Any thoughts concerning equipment or techniques would be greatly appreciated.< Looking at the results of a little 'steadishot' test I used when reviewing some 'palmcorders', I was amazed how good the images were. Unless you are on a very flat surface, you are going to get some vibration, and this will 'equalise' the performance of lesser cameras to better models. The main problem with shooting in a car is getting a wide enough angle, and a small palmcorder can be mounted almost flat against the windows/windshield and thus furthest away from the subjects. I used a US made device called a Wood's Powr-Grip(6in size), which is basically a rubber 'sucker' with a little hand pump to create a 'vacuum'. It is really meant for holding lights but it will support most consumer cameras with no problem, as long as a smooth surface like glass is being used. You can then use the camcorders LCD screen rotated forward to set the exact shot. I found the electronic stabilisers worked better than the optical with a lot of bouncing on rough tracks. It may be slightly disconcerting that the shot will stabilise on the outside view rather than the inside subjects. Before you spend a fortune on lots of fancy pro camera mounting kit, give this a try and see what you think. If you don't want to use lights, choose a car with light colored cloth upholstery and a glass sun roof. When shooting forwards, remember to move the mirrors to get a nice image of the driver's face. good luck Perry Mitchell Video Facilities http://www.perrybits.co.uk/ (diese posts stammen von der DV-L Mailingliste - THX to Adam Wilt and Perry Mitchell :-) [up] |
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