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Old December 30th, 2004, 01:04 PM   #16
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It depends on the thickness of the wax. If it's thin enough, you can get a very bright image. I just recently got a really thin layered wax adapter, but I want to do another and shoot for a completely bubble-free version. If I succeed, I will post some uncompressed framegrabs comparing it and my AO5 glass adapter.
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Old December 30th, 2004, 01:36 PM   #17
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ground glass test

I think this is a shot made with the opto sigma 1500

http://www.liisikoikson.com/ftp/noise_redux_ex.jpg


this also contains the chris rubin workflow
which looks to remove whats left of the grain in a static adapter
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Old December 30th, 2004, 09:20 PM   #18
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Richard,

that is not optosigma, but a 600 grit sandblasted glass. Optosigma gg grain is much finer and not really visible on a fine-detail image of that particular size.

Chris
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Old December 31st, 2004, 03:24 AM   #19
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So, there would be hardly any grain from a 1500 GG? I wonder, what is the difference between grinding your own glass, and buying one premade? Does it work out alot more cost effective D-I-Y, or do you get a better image with a bought glass?
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Old December 31st, 2004, 09:15 AM   #20
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ground glass

chris your first image ,did look like more grain then I am seeing
with the 1500 ,. and maybe a good indicator of what the royln 500 grit will look like.


and for all my efforts hand grinding, I was never able to make a piece of glass as good as the one I am using now.

the next idea is to see if we could get the company to cement the ground glass to the plcx in a dust free room .

dust is my biggest problem now
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Old December 31st, 2004, 10:12 AM   #21
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static adapter

chris I may be adding a second plcx to the adapter.
I just tested the system on a tv chart and I am seeing a slight barrel distortion. I think a matching plcx on the opposite side will correct this . this is a link to a german patent for the movie tube
it has a wax diffuser in between two plcx . If we could get opto sigma to make this as one piece we would be set .
I don,t think we have to worry about patent infringment
because we are mearly buying off the shelf lenses and arranging them in a specific order in the tube and sharing the order

http://v3.espacenet.com/textdoc?DB=E...QPN=DE10240076
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Old January 1st, 2005, 04:18 AM   #22
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Richard, do you have any idea if OptoSigma take international orders? I had a look at their international page, but it was more for a laser optics firm that stocked OS equiptment related to lasers. If not, have you seen any optics sites that may ship the UK?
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Old January 1st, 2005, 06:59 AM   #23
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Steve,

The Optosigma dealer in the UK is:

http://www.laser2000.co.uk/

Richard, I use this in my adapter:

http://www.surplusshed.com/pages/item/l2030.html

No barrel distortion, but difficult to position inside the adapter because it has no flat surfaces. I'm still working on it, but I'm sure I'll get it done.
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Old January 1st, 2005, 07:33 AM   #24
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Chris, thanks for the link, the trouble is it seems they don't stockground glasses there, just the laser side of OptoSigma. Now, I may be wrong, but I'll give them an e-mail to see if they do the ground glasses. Also, what camera were you using in your test, Chris?
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Old January 1st, 2005, 08:06 AM   #25
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Steve,

that was XL1 with stock lens
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Old January 1st, 2005, 06:16 PM   #26
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Richard Mellor-
Increase the distance between your GG and video camera a few inches and zoom in a bit more to reframe again.

You shouldnt have any more barrel distortion problems.
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Old January 1st, 2005, 06:28 PM   #27
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i got barrel distortion with my adapter.
condenser as GG and macro only.
Then i add a lens (looks like a huge contact lens) between the macro and the GG-condenser.
moving back and forth vary the barrel effect (positively and negatively) but a finally found a position where barrel disappear.
The best of all it is that it gives me the brightest picture i ever dream and totally remove the vignetting.
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Old January 3rd, 2005, 02:22 AM   #28
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Giroud, you say your adaptor gives a bright image, could you perhaps divulge any more information about the type of lenses your using, ect?
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Old January 3rd, 2005, 12:53 PM   #29
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static adapter

brett :I added a1/2 inch tube to the system as per your advice. and your right the barrel distortion is gone.
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Old January 3rd, 2005, 01:24 PM   #30
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as many builder, i unfortunately work with refurbished elements wit very few (if none) data about them.
My GG is a lense 55mm diam very thin (1mm in the border and 6 mm in the center).
It has been taken off of a TV camera lense (Fujinon-TV Z 1:1.7/10-140), one of the front lens.
The macro is a 52mm achromat from surplus shed, but except diameter , i have no information (works well with my VX2000)
the "contact lens like) is another lens from the fujinon.
For the GG i used AL. oxyde 1000.
I is very fast to obtain the proper result (when the lens is flat!), because almost every lens i tested until now, is never really flat, so the first stage is to use abrasive paper (starting with 200 then 600 ) to make it flat.
fortunately, the result is almost perfect, with no grain visible in normal light. Low light with iris closed increase the grain visibility, but having filmed at night, i can say it still workable.
The real secret is to have a 35mm lens with big output.
Most of lenses have a rear lens with diam. ranging from 15mm to 20mm. So you get a small bright output just behing the GG.
So when the camera see the GG, if it is not really opaque, you can see the bright spot.
I use now a Nikkor 1:1.4 that has a 30mm rear lens.
if you compare to the diameter of the GG picture (about 47mm)
you can imagine that really make a difference.
additionally the angle of incoming light on the GG is a lot better.
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