Hey Russ,
No arguements ever from me on any forum. I know better. If I have knowlege about something and I can contribute in a positive fashion, I do. Since I know nothing about chainsaws and you guys do, I mostly read rather than write.
First, battery voltage. That's not an issue here as these things have internal regulators that keep the recorder running at some fixed lower voltage than the battery puts out. If the battery puts out say 7.2V, maybe the recorder needs 6V. The regulator is set to output a constant 6V and keeps the recorder happy as the battery voltage discharges from 7.2V to something under 6.5V, but above 6V (the regulator needs some voltage across it to work, this example sites a linear rather than a switchmode regulator). Once the battery voltage gets below a preset level, the camera stops working completely. Up until this point, the camera exhibits no ill timing or other effects, ie: it works 100%, then you get a low battery indicator and the camera shuts down shortly afterward.
Yes, there is absolute time delay in any electronic circuit. From the time the event happens to when it is recorded on tape is small, but it exists. The key here is to keep all appropriate signals, regardless of frequency and electrical path length, equal in relative delay. Once you do this, absolute delay doesn't matter at all.
You are correct in regard toward not using video for exact timing as per what I said before in regard toward the 1/30 or a second minimum resolution. In one frame, the saw chain is in the wood and the very next frame it isn't. That's .033 seconds of uncertainty, period. Not very accurate for timing situations that require precision down to .01 or even .001 second, but it will get you in the ballpark for informal use as in "1.16 to 1.18" second cut times. As far as the video of the cut went, assuming that the error in the stopwatch actuation was accurate, one could confidently say that the cut took 1.17 +/- .043 seconds based on ones observation of the video. This takes into account the initial +/-.01 second variance and a +/- .033 second potential maximum video frame time resolution.
Video boards in computers are different animals. Much of what makes some video cards better than others involves their ability to better process the graphics required for more realistic presentation of animated video. This is far more difficult than what is required for full motion real video. We're all used to TV. TV is a walk in the park compared to what computers have to do when it comes to animation.
Video is very limited in timing accuracy, but film on the other hand is much better. Standard motion picture cameras run at 24 frames per second (less than video), the faster you run the film, the more sensitive it has to be to light. The Imacon motion camera runs at 300 million frames per second giving it a native time resolution of a little over 3 billionths of a second (light and electricity would travel about 3 feet in this time span).
Well, I've wasted enough of this board's time with my babbling about electronics. Hope I've made this clearer rather than muddier. Sorry for the verbosity. Back to chainsaws.
