Best GG Diffuser?

Frank Ladner · December 30th, 2004, 01:04 PM

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.

Richard Mellor · December 30th, 2004, 01:36 PM

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

Chris Rubin · December 30th, 2004, 09:20 PM

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

Steve Wardale · December 31st, 2004, 03:24 AM

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?

Richard Mellor · December 31st, 2004, 09:15 AM

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

Richard Mellor · December 31st, 2004, 10:12 AM

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

Steve Wardale · January 1st, 2005, 04:18 AM

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?

Chris Rubin · January 1st, 2005, 06:59 AM

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.

Steve Wardale · January 1st, 2005, 07:33 AM

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?

Chris Rubin · January 1st, 2005, 08:06 AM

Steve,

that was XL1 with stock lens

Brett Erskine · January 1st, 2005, 06:16 PM

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.

Giroud Francois · January 1st, 2005, 06:28 PM

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.

Steve Wardale · January 3rd, 2005, 02:22 AM

Giroud, you say your adaptor gives a bright image, could you perhaps divulge any more information about the type of lenses your using, ect?

Richard Mellor · January 3rd, 2005, 12:53 PM

brett :I added a1/2 inch tube to the system as per your advice. and your right the barrel distortion is gone.

Giroud Francois · January 3rd, 2005, 01:24 PM

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.

December 30th, 2004, 01:36 PM	#17
Richard Mellor Major Player Join Date: Nov 2003 Location: cambridge ma Posts: 247	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

December 31st, 2004, 09:15 AM	#20
Richard Mellor Major Player Join Date: Nov 2003 Location: cambridge ma Posts: 247	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

December 31st, 2004, 10:12 AM	#21
Richard Mellor Major Player Join Date: Nov 2003 Location: cambridge ma Posts: 247	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

January 3rd, 2005, 12:53 PM	#29
Richard Mellor Major Player Join Date: Nov 2003 Location: cambridge ma Posts: 247	static adapter brett :I added a1/2 inch tube to the system as per your advice. and your right the barrel distortion is gone.

December 30th, 2004, 01:04 PM	#16
Frank Ladner Major Player Join Date: Aug 2003 Location: Poplarville, MS Posts: 453	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.

December 30th, 2004, 09:20 PM	#18
Chris Rubin Regular Crew Join Date: Jul 2004 Posts: 38	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

December 31st, 2004, 03:24 AM	#19
Steve Wardale Regular Crew Join Date: Apr 2004 Location: Lincoln, UK Posts: 43	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?

January 1st, 2005, 04:18 AM	#22
Steve Wardale Regular Crew Join Date: Apr 2004 Location: Lincoln, UK Posts: 43	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?

January 1st, 2005, 06:59 AM	#23
Chris Rubin Regular Crew Join Date: Jul 2004 Posts: 38	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.

January 1st, 2005, 07:33 AM	#24
Steve Wardale Regular Crew Join Date: Apr 2004 Location: Lincoln, UK Posts: 43	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?

January 1st, 2005, 08:06 AM	#25
Chris Rubin Regular Crew Join Date: Jul 2004 Posts: 38	Steve, that was XL1 with stock lens

January 1st, 2005, 06:16 PM	#26
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	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.

January 1st, 2005, 06:28 PM	#27
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	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.

January 3rd, 2005, 02:22 AM	#28
Steve Wardale Regular Crew Join Date: Apr 2004 Location: Lincoln, UK Posts: 43	Giroud, you say your adaptor gives a bright image, could you perhaps divulge any more information about the type of lenses your using, ect?

January 3rd, 2005, 01:24 PM	#30
Giroud Francois Inner Circle Join Date: Feb 2004 Location: switzerland Posts: 2,133	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.