Mini35 Oscillating Ground Glass Idea

Les Dit · August 31st, 2004, 10:58 PM

Ray, I just used the GG and 50mm lens, no condenser lens used. It does get a tad darker on the edges, but not much.
My assembly is only 3.5 inches in diameter, so the motor has to be offset with a mounting plate.
-Les

Bob Hart · September 2nd, 2004, 02:47 AM

Les.

Did you receive the DVD+R disk yet?

Les Dit · September 2nd, 2004, 10:27 AM

Yes Bob, Sorry, I meant to reply but I was sidetracked!
The footage looks great, there is really no grain or other artifacting going on. Good work!
Thanks again!
-Les

<<<-- Originally posted by Bob Hart : Les.

Did you receive the DVD+R disk yet? -->>>

Joel Aaron · September 2nd, 2004, 06:34 PM

Les, could you email me a link to your footage?

film AT bigsmile.com

Also, do you have any photos of your unit? That would be very helpful too.

Thanks!

Jesse Rosten · September 9th, 2004, 10:07 AM

Hey Les,

I wouldn't mind seeing that footage of yours. Can you link me up?

elrosten@yahoo.com

thanks

Les Dit · September 9th, 2004, 11:53 AM

OK, link sent. Let me know what you think!

Jesse Rosten · September 9th, 2004, 02:04 PM

Looks great. I see no grain. And I'm sure the jitter will go away when the unit is mounted solidly to the camera.

This may have been mentioned a while back, but by oscillating a focus screen ( like from a 35mm or medium format camera) with a fresnel already "built-in" to the ground glass, you should be able to do away with all the condensor madness. The fresnel lines should be invisible because the screen is moving.

anyways... What's the noise level on your oscillator?

Frank Ladner · September 9th, 2004, 02:09 PM

It seems like the fresnel type ground glasses are built with the rings relative to the center of light, so that it distributes the light across the plane. Rotating a fresnel with the axis being along the center of the rings would work, surely, but would oscillating it work without having some jittery unevenness? Does this make sense? Sorry if I've confused anyone.

Les Dit · September 9th, 2004, 02:29 PM

Jesse,
I didn't use a condenser on that test. Did you notice?
-Les

Jesse Rosten · September 9th, 2004, 02:37 PM

Yes, Les, The vignette was quite obvious. I wasn't trying to imply that you WERE using a condenser. - Just thinking aloud about the possibility of oscillating a fresnel-type focus screen.

peace
jesse

Brett Erskine · September 10th, 2004, 02:17 AM

"This may have been mentioned a while back, but by oscillating a focus screen ( like from a 35mm or medium format camera) with a fresnel already "built-in" to the ground glass, you should be able to do away with all the condensor madness. The fresnel lines should be invisible because the screen is moving."

Unfortunately you cant do this without another problem showing up. If you do you'll find out that your hot spot has suddenly reappeared when the fresnel is put into motion.

This happens because the fresnel is focusing light roughly to one point. When you move the fresnel in any way your changing where that point is pointed as it relates to the CCD's. Bigger the motion worse the hot spot effect will be. Now IF you could get it to oscillate in a path that is extremely tight (I mean no more than 1 or 2mm) then it shouldnt cause any problems at all. But having such a small movement means you'll have to move it quite a bit faster in order for the grain of the GG to "disappear". This is exactly what Im currently attempting to do. I'll let you all know if it works.

Rabi Syid · September 24th, 2004, 11:05 AM

<<<-- Originally posted by Les Dit : OK, link sent. Let me know what you think! -->>>

hi

can i see the footage as well. also has anything really come of the oscilating GG idea. im planning to shoot with and xl2 and some sort of homemade mini35 device with can ef lenses.

lilbowrabi@hotmail.com

Rabi Syid · September 24th, 2004, 11:05 AM

<<<-- Originally posted by Les Dit : OK, link sent. Let me know what you think! -->>>

hi

can i see the footage as well. also has anything really come of the oscilating GG idea. im planning to shoot with and xl2 and some sort of homemade mini35 device with can ef lenses.

lilbowrabi@hotmail.com

Les Dit · September 24th, 2004, 12:17 PM

Link sent.
-Les

Obin Olson · September 27th, 2004, 07:00 AM

I want to see!

oolsen1@ec.rr.com

September 10th, 2004, 02:17 AM	#161
Brett Erskine Major Player Join Date: Dec 2003 Location: Anaheim, CA Posts: 445	Oscillating a one piece fresnel/GG "This may have been mentioned a while back, but by oscillating a focus screen ( like from a 35mm or medium format camera) with a fresnel already "built-in" to the ground glass, you should be able to do away with all the condensor madness. The fresnel lines should be invisible because the screen is moving." Unfortunately you cant do this without another problem showing up. If you do you'll find out that your hot spot has suddenly reappeared when the fresnel is put into motion. This happens because the fresnel is focusing light roughly to one point. When you move the fresnel in any way your changing where that point is pointed as it relates to the CCD's. Bigger the motion worse the hot spot effect will be. Now IF you could get it to oscillate in a path that is extremely tight (I mean no more than 1 or 2mm) then it shouldnt cause any problems at all. But having such a small movement means you'll have to move it quite a bit faster in order for the grain of the GG to "disappear". This is exactly what Im currently attempting to do. I'll let you all know if it works.

August 31st, 2004, 10:58 PM	#151
Les Dit Major Player Join Date: Oct 2003 Location: Southern Cal-ee-for-Ni-ya Posts: 608	Ray, I just used the GG and 50mm lens, no condenser lens used. It does get a tad darker on the edges, but not much. My assembly is only 3.5 inches in diameter, so the motor has to be offset with a mounting plate. -Les

September 2nd, 2004, 02:47 AM	#152
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,476	Les. Did you receive the DVD+R disk yet?

September 2nd, 2004, 10:27 AM	#153
Les Dit Major Player Join Date: Oct 2003 Location: Southern Cal-ee-for-Ni-ya Posts: 608	Yes Bob, Sorry, I meant to reply but I was sidetracked! The footage looks great, there is really no grain or other artifacting going on. Good work! Thanks again! -Les <<<-- Originally posted by Bob Hart : Les. Did you receive the DVD+R disk yet? -->>>

September 2nd, 2004, 06:34 PM	#154
Joel Aaron Major Player Join Date: Jul 2004 Location: Phoenix, AZ - USA Posts: 300	Les, could you email me a link to your footage? film AT bigsmile.com Also, do you have any photos of your unit? That would be very helpful too. Thanks!

September 9th, 2004, 10:07 AM	#155
Jesse Rosten Regular Crew Join Date: Mar 2004 Location: Redding, California Posts: 114	Hey Les, I wouldn't mind seeing that footage of yours. Can you link me up? elrosten@yahoo.com thanks

September 9th, 2004, 11:53 AM	#156
Les Dit Major Player Join Date: Oct 2003 Location: Southern Cal-ee-for-Ni-ya Posts: 608	OK, link sent. Let me know what you think!

September 9th, 2004, 02:04 PM	#157
Jesse Rosten Regular Crew Join Date: Mar 2004 Location: Redding, California Posts: 114	Looks great. I see no grain. And I'm sure the jitter will go away when the unit is mounted solidly to the camera. This may have been mentioned a while back, but by oscillating a focus screen ( like from a 35mm or medium format camera) with a fresnel already "built-in" to the ground glass, you should be able to do away with all the condensor madness. The fresnel lines should be invisible because the screen is moving. anyways... What's the noise level on your oscillator?

September 9th, 2004, 02:09 PM	#158
Frank Ladner Major Player Join Date: Aug 2003 Location: Poplarville, MS Posts: 453	It seems like the fresnel type ground glasses are built with the rings relative to the center of light, so that it distributes the light across the plane. Rotating a fresnel with the axis being along the center of the rings would work, surely, but would oscillating it work without having some jittery unevenness? Does this make sense? Sorry if I've confused anyone.

September 9th, 2004, 02:29 PM	#159
Les Dit Major Player Join Date: Oct 2003 Location: Southern Cal-ee-for-Ni-ya Posts: 608	Jesse, I didn't use a condenser on that test. Did you notice? -Les

September 9th, 2004, 02:37 PM	#160
Jesse Rosten Regular Crew Join Date: Mar 2004 Location: Redding, California Posts: 114	Yes, Les, The vignette was quite obvious. I wasn't trying to imply that you WERE using a condenser. - Just thinking aloud about the possibility of oscillating a fresnel-type focus screen. peace jesse

September 24th, 2004, 11:05 AM	#162
Rabi Syid Regular Crew Join Date: Sep 2004 Location: location Posts: 68	<<<-- Originally posted by Les Dit : OK, link sent. Let me know what you think! -->>> hi can i see the footage as well. also has anything really come of the oscilating GG idea. im planning to shoot with and xl2 and some sort of homemade mini35 device with can ef lenses. lilbowrabi@hotmail.com

September 24th, 2004, 11:05 AM	#163
Rabi Syid Regular Crew Join Date: Sep 2004 Location: location Posts: 68	<<<-- Originally posted by Les Dit : OK, link sent. Let me know what you think! -->>> hi can i see the footage as well. also has anything really come of the oscilating GG idea. im planning to shoot with and xl2 and some sort of homemade mini35 device with can ef lenses. lilbowrabi@hotmail.com

September 24th, 2004, 12:17 PM	#164
Les Dit Major Player Join Date: Oct 2003 Location: Southern Cal-ee-for-Ni-ya Posts: 608	Link sent. -Les

September 27th, 2004, 07:00 AM	#165
Obin Olson Trustee Join Date: Jan 2003 Location: Wilmington NC Posts: 1,414	I want to see! oolsen1@ec.rr.com