From: Bruce Maccabee <firstname.lastname@example.org> Date: Tue, 19 Jan 1999 10:30:55 -0500 Fwd Date: Tue, 19 Jan 1999 13:05:08 -0500 Subject: Re: 'Rods' - On The Learning Channel >From: Roger Evans <email@example.com> >Date: Mon, 18 Jan 1999 11:02:28 +0000 >To: UFO UpDates - Toronto <firstname.lastname@example.org> >Subject: 'Rods' - On The Learning Channel >>From: Jose Escamilla <email@example.com> >>Date: Sun, 17 Jan 1999 13:15:46 +0300 >>Fwd Date: Sun, 17 Jan 1999 15:57:23 -0500 >>Subject: 'Rods' - On The Learning Channel> >Previously, Jose had written: >>So, in our quest to further this investigation, Jim Peters, Ken >>Swartz (a new associate and team member), set out to see "if in >>fact" Rods or fast objects traveling distances from the camera >>would create a "blur" because of the electronics involved in CCD >>photography - or videography. >>We videotaped an 16 1/2"arrow (bolt) using Jim's crossbow that >>shoots these bolts at approximately 136 mph. >>We used the Sony VX-1000 digital >>camcorder that most of the current Rod shots have been captured >>on in New Jersey, South Dakota and The cave in Mexico. >>>We we found was that using the optical lens setting at 1/10,000 >>shutter setting, the bolt - or arrow, appears as it really is: a >>16 1/2" arrow. And it appears in two to three frame of video >>shot at 30fps.> >>This revealed to us that using the Sony VX-1000 camcorder as has >>been used in all the cave footage, what you see is what you get.> >Hi Jose, >To start with, I'm not at all up to date on the ROD issue, but I >do know a thing or two about video. I can appreciate the test >you were trying to create but there are a couple of things you >really should consider: >1) 1/10,000 of a second shutter is staggeringly fast. Therefore >little, if any, blur should be expected of any object at that >speed. >6) If the arrow was traveling at 136 mph, I'm surprised it would >show up at all on the video beyond one frame. If, on the other >hand, you were looking at "fields" instead of "frames", then I >might buy that. While there are 30 frames per second, there are >actually 60 fields per second (2 fields per frame is the easiest >way to remember it for future reference). Some VCRs allow for >single field viewing; some single frame viewing; some both. You >need to check your machine for the specifics.> >Try taking these things into consideration and run another test (CALCULATION BY BSM: Sounds like a good experiment.) At 136 mph = 200 ft/sec in 1/30 sec it will go 200 x 1/30 = 6.67 ft. At 10 ft the angular shift in position (perpendicular to the line of sight is assumed) 2 tan^-1[(6.67/2)/10] = 36 degrees. If the camera field of view were 40 degrees there could be 1 or two frames. (Note: I don't know what the field of view left-to-right was.) During the shutter time it would move 200 x 1/10000 = 2/100 = 0.02 ft = 0.24 inches. This is 0.015 of its 16.5" length... that is, a 1% smear of the length...hardly noticeable. Not surprising it looks like what it is...a "bolt". Even at 1/1000 the smear wouldn't be horrible (10% of the length). He said he had poles 24 feet apart. Obviously at a 10 ft distance the poles wouldn't show in the field of view if the camera were halfway between the poles and 10 ft from the ribbon. At 100 ft, the angular spacing between poles is tan^-1(.24) = 13 degrees, which could have been within the field of view. At any rate, between frames the bolt would go 6.67 ft which is an angle of tan^-1(6.67/100) = 3.8 degrees at 100 ft distance. Hence in any reasonable (non-zoomed) field of view the bolt would appear in several frames. For example, it could easily appear in 5 successive frames (19 degrees of angular distance) of the field of vew were 30 degrees. Again, the smear of the bolt image would be about 1% of its length at 1/10000 sec shutter speed. Jose says his big test was to use the electronic zoom to zoom in on the central section of a 6 ft long section of the ribbon (marked by black lines?) from a distance of 100 ft. The angle between the 6 ft marker was tan^-1(.06) = 3.4 degrees. His zoom may have restricted the field of view even more. At any rate, he would get the bolt in only 1 frame. His test showed overall blur...perhaps not surprising. It should be compared with the blur of the ribbon image. However, in any case, the motion smear of the bolt was only about 1% of its length so any noticeable blur was due to the camera/optical system and not the motion.
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