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Old April 20th, 2004, 05:46 PM   #46
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Quote:
Maybe Andre can use the "raytracing programs" and tell us the results when we use this:
What does this have to do with using wide angle adaptors to lower LUX requirements of the PV-DV953?
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Old April 20th, 2004, 06:10 PM   #47
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a program like this should be able to report the net-change of the light falling on the CCD after you put the 85mm wide-angle adaptor.

you know what.. enough is enough...
i'm out of here... =)
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Old April 20th, 2004, 06:30 PM   #48
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Frank, he's funny eh?

BTW, no, a ray tracing program does not report such information.
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Old April 20th, 2004, 06:41 PM   #49
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Well, I don't know anything about this program. That's why I asked about it; and I don't have a broadcast engineering background like Andre. Though I hope he can do some scientific LUX measurement tests for us with the PV-DV953 (or GS500, or XL1, etc) and a wide angle lens. I'm looking forward to his results. It should be good reading.
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Old April 21st, 2004, 09:57 AM   #50
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Well Bob I am not shure if you ever used a raytracing program because you then should know that those programs do a lot mors than just show how the rays are bend...
Setting up a project for raytracing for convertor lens principles is beyond the targets of this forum I think...and takes some time.
Two further remarks:
1.I just verified my VX2000 (in full manual mode with and without the Canon WD58 at 50IRE for the central image part. Result: no measurable change in IRE levels. I hope some body else will do the test too...for the non-believers.
2 George. it's not allways easy to "explain" how optical components believe, but I will give it a try:
A wide angle convertor lens is in it's basic form a large positive lens and a smaller negative lens at a distance (like 1") well within the focal distance of the positive lens. Both lenses have the same power but with opposite sign. The positive lens "collects" (bundles) the incoming light on an area much larger than the negative lens area. So only part of that collected light is being used for further transmission through the negative lens. Why this "loss"? Well off axis image points have still to shed enough light on the negative lens in order to avoid off axis light fall-off. In optical terms this means that the image field area at the negative lens plane is much larger than the lens area. Still questions?
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Old April 21st, 2004, 11:14 AM   #51
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Yes. When I was with SGI and Pixar I wrote ray tracing programs.

The problem is he wants visual proof and not "talk".
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Old April 21st, 2004, 02:16 PM   #52
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Bob, I do know those companies and there research in raytracing and radiosity for synthetic image rendering, but "raytracing" in the geometric optics (lens design) world is not at all related to that. Download e.g. the free "Winlens" program and you will see what it is all about raytracing in optics.
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Old April 21st, 2004, 04:13 PM   #53
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Thanx Andre =)
(finally someone who knows what he's talking about Rob)

Andre, actually I was wondering if there is actual improvement after pieces like Aspheron 85mm
http://www.fortvir.net/albums/tom-s-...ture.sized.jpg

I know that there are imperfections, but as a whole what would the net effect be? So I was asking for someone to test it if he can, that is. Thank you.
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Old April 22nd, 2004, 03:44 AM   #54
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George, I'am happy I could give you a feeling about that stuff. Unfortunately, I can't help you any further on the Aspheron product. I suppose it contains aspherical lens elements like most wide convertors do. It used to be difficult and expensive to manufacture aspheric lens elements but since acrylic lens production technology is well mastered, most consumer cam optics (not only the convertors)contain internal aspherical components. This is much cheaper than using a bunch of different refractive index glass components to fight all kinds of aberations and distortions. If I would buy such a convertor I would first screw it on my cam and see what happens, because depending on your own optics (mainly wide properties) you could end up in vignetting, and/or excessive brightness fall-of in the corners.
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Old April 22nd, 2004, 09:53 AM   #55
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Thanx Andre, I was planing to do the same thing =)
I'll have to wait to get the gs400 cam first =/
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