Entries categorized as ‘Q&A’
A Reader Asks
“I own a Nikon strobe. Can I use the same radio trigger I use on the Nikon to power my Canon strobe?”
Firstly to clarify: Radio Triggers really do not “power” anything. One cannot easily transmit power wirelessly (although Nikola Tesla would argue that fact). They are basically relays or switches that are controlled by a radio signal.
Radio controlled flash triggers are “device agnostic.” It is just an extension of your camera’s synch switch and circuitry. They have worked with most any photoflash device I have teamed them with — Canon, Nikon, Norman, Photogenic, Lumedyne, Broncolor and more.
One thing to consider, some wireless flash triggers will serially transmit your camera’s exposure data along the data stream in multi-lighting setups using the same flash and camera system (i.e. Nikon to Nikon, Canon to Canon) If you cross systems you will likely still be able to trigger the remote flash but it may not or will not be able to transmit the exposure data. -33-
Categories: Photography · Q&A
A Reader Asks
“I’m debating using projections or a series of stacked televisions for an upcoming theatrical production. I’m picturing a tower of televisions of multiple sizes on either side of the stage. The images on the televisions would be the same. Nothing fancy like an image traveling down from the top to the bottom or one image being stretched over multiple televisions.
Initial thoughts: They are all daisy chained together and hooked to a single DVD or VCR. But, how do you control them if there are periods where they wouldn’t be used?”
What you are describing is a pretty common setup. I would not recommend simply turning your video monitors on and off because some televisions will reset to a default state if they are disconnected from power and that default state might not be what you want it to wake-up in. What you need is a vertical interval video switch and a black burst generator. These devices will send black video to mute the screen when not in use. You also may want to mute the sound too. A solution for this would be a vertical interval “Audio Follow Video” switch. All “vertical interval” means is that it will switch your video seamlessly without a big break-up (glitch) on the screens.
As far as interconnection, when you are sending the same source signal to all the video monitors it is seldom a good idea to “Daisy-Chain” an audio or video signal, especially when it comes from a relatively weak source device like a consumer DVD or VCR. I strongly recommend a device called a Video Distribution Amplifier. You also would need an Audio Distribution Amplifier if you are going to send the same audio to all the television monitors.
I know you said you had a single source but if you wanted to send a different signal to all the monitors or do fancy images that would go from a different picture on every screen to a big blow up of a single image using all the screens there is a solution for that too. You could get software driven system that would do this automatically for you. They are expensive but rentable at a fairly reasonable cost if you are a one and done kind of user. -33-
Categories: Q&A · Video
A Reader Asks
“Which Piano Notes do Touch-Tone Dial Frequencies Generate?”
There are 8 frequencies that, when set in an X-Y Matrix combine to produce 16 dual tones. The frequencies are set in two groups. (All frequencies are in Hz).
High Group
1209
1336
1477
1633
Low Group
941
852
770
697
The combinations and what they create are as follows:
1=697+1209
2=697+1336
3=697+1477
A=697+1663
4=770+1209
5=770+1336
6=770+1477
B=770+1663
7=852+1209
8=852+1336
9=852+1477
*=941+1209
0=941+1336
#=941+1477
D=941+1663
SIDEBAR — The letters A, B, C and D are not commonly found on your typical telephone set. They are used for special signaling and switching operations the consumer might need with special software or home equipment.
Let’s use the given that A4 is 440Hz and Middle C is 256Hz. These also happen to be standard audio calibration frequencies used for certain calibrations and setups.
Cheating a bit an equation was not used to calculate the frequency vs. musical notes. I did a comparison against some technical information I have in my Standards and Practices tech files. This will get us in the ballpark. Most of these have a tolerance of +/- 50 cents. Here is what we discover:
1209 (High side of D6)
1336 (High side of E6)
1477 (Low side of F#6)
1633 (Low side of G#6)
941 (Low side of A#5)
852 (High side of G#5)
770 (Low side of G5)
697 (Low side of F5)
As you can see the frequencies do not match musical notes exactly. This is because the frequencies were chosen by design to avoid dialing mistakes by familiar ambient sounds picked-up by the telephone’s receiver (microphone). Technically, if the frequencies matched exactly, misdialing might occur if there was music playing while one was dialing. The frequencies were also chosen so as not to interfere with other telephone tones used in the network for operations like billing, call transfers and other telemetry used to advance telephone calls. -33-
Categories: Audio · Q&A
A Reader Asks
”I recently heard of television programming that is available on IPTV. Can you please tell me what that means?”
IPTV (Internet Protocol Television) is a method of delivering television services in the form of IP (Internet Protocol) Packets. When these “Packets” reach your home the converter box on top of your TV converts, or more technically “Decodes” these to a signal that your television can translate and deliver programming to you.
IPTV is a very secure, closed system with content controlled by the service provider. There is a high level of quality and control connected with IPTV. This is totally different from a confusingly similar sounding technology named Internet TV where video is streamed over the Internet to your computer. An example of Internet TV might be YouTUBE® or some of the many other similar services available on the Web. These services are typically presented at a much lower quality than IPTV.
IPTV allows a two-way street promoting interaction with the program materials and On-Demand services. Typically streaming video is a one-way street with few viewing options. This two-way street also allows the service provider to “sneak a peek” at the viewing trends of their viewers and adjust offerings and advertising accordingly.
Unlike current Cable and Fiber technologies being transmitted directly to the user’s home IPTV content is transmitted to a central office where the analog or digital television signals are “Encoded” into data packets, indexed for searching and stored in memory waiting for the consumer to call-up their favorite show. These data travel to the consumer’s home and are “Decoded” to standard television signals for use on a standard TV receiver.
Eavesdropping on your viewing habits is not the only benefit of IPTV’s interactive nature. This can also help engineers optimize the signals delivered across the service provider’s entire region. For example, let us consider five communities in a particular area. If areas one and three are heavy users but two, four and five are not consuming as much of the bandwidth, adjustments to the system could be made instantaneously to divert more signal resources to the heaver use areas and balance the unused bandwidth against the demanded bandwidth. When the lower use communities demand increases they could be fed more bandwidth to meet demand.
Basically IPTV technology provides much greater control over technical resources and allows for customized, technical quality control as needed by demand. This allows for a much more cost effective network than one that sends the same “Power” to all consumers without regard to usage trends.
In the United States IPTV is not a widely embraced technology. There are about 1.2 Million IPTV subscribers in the United States. In comparison there are approximately 90 Million subscribers to satellite, cable and fiber services. -33-
Categories: Q&A
A READER ASKS
What can I do to obsolete proof my video archives? Most of them are on Beta SP®. Do I need to go to a Duplication House to have copies made?
Just a few quick thoughts:
FORMAT HOP
If you are looking for long-term storage of your program materials your best bet is to format hop as new formats develop. Beta SP® (A Trademark of Sony) is an analog format. An important issue with analog is that it does not copy into multiple generations well, although Beta SP® is one of the better formats for multi-generation duplication because signal quality holds up through several copies.
GO DIGITAL
You should consider converting your program materials to a digital format (this is called “Digitizing”). To do this you would have your Beta SP® original digitized and placed on a DVD as a MPEG file. This is not a complicated process. You can simply go to your favorite electronics store, purchase a DVD player/recorder and connect it to a Betacam® VTR and you are on your way.
Once it is in a digital format it can maintain the visual and audio quality of the original software. This means that you can make copies of copies with little to no loss in quality.
BE READY TO JUMP SHIP
Format hopping comes in when you begin to see DVDs and MPEG formats slipping in popularity. Always go with the latest stable format to duplicate your materials. It is a lot of follow-up but well worth the effort to protect today’s program materials for generations to come. This is a big problem for still photographers. Many question if archived images taken today will be able to be opened for viewing 50, 75, 100… years from now. -33-
Categories: Q&A · Video
