Quartz Aldu35mm Adaptor at DVinfo.net

Matt Champagne · November 7th, 2004, 10:29 PM

I asked this in another thread, but I thought maybe it might deserve its own thread.

Can Quartz be used as the ground glass portion of something simular to the static Aldu25 adaptor. The reason to do this would be because you could use the piezoeletric properties of quartz to cause it to oscilate...probably with very little noise. And if I needed to grind it myself, could glass be used as the grinding or would you have to use a second piece of quartz to prevent scratching or something.

To make it oscillate would be very simple. Just create an oscilator circuit to convert DC to simulated AC from a battery. Problem 1...it may create an audible tone around 1Mhz - 10Hhz. Problem 2...it may create a short wave radio signal which could mess with camera operation (though I kinda doubt it).

If anyone would want to give it a go, this might be a descent source for quartz.

http://www.2spi.com/catalog/ltmic/quartz.shtml

It's a bit pricey and I'm just a poor college student...so I don't want to order and start testing this all out until I get at least some confirmation that quartz could be ground properly to do this with it.

Matt

Bob Hart · November 8th, 2004, 02:16 AM

On electronics I am totally dumb.

If you take to your quartz to make it conform to a thin plate shape and roughen one surface for a reverse projection screen :-

Do you destroy the integrity of the crystal and thus its ability to resonate?

Don't you need a single whole crystal to make a resonant circuit?

Does the crystal itself in resonating to an AC current not change size over its entire strucure?

The magnitude of any resonant change in dimension might be so small as to be insufficient. My imagining is that it would have to be a humungous big crystal with the optical path through a tiny part of one end of it.

Assuming the crystal can be found which is big enough to create enough groundglass movement within itself, what is its fundimental resonant frequency, pretty low, maybe too low not to be itself resolved by the camcorder as a visible movement.

Handy to carry around. - Too thick to fit within the flange to focal plane?

Ignacio Rodriguez · November 8th, 2004, 09:22 AM

At 1 MHz and way below it will not be audible. Most old school TV sets oscilate at 15 KHz (quite audible for most people under 60) and nobody seems to mind much. Anything over 25 KHz will not be audible to humans. Cat's and dogs might have trouble with it, so stay over 200 KHz if you can.

Matt Champagne · November 8th, 2004, 04:51 PM

BOB: To answer a few of the questions all at once, what you would need is a quartz lens made out of a single crystal attached to an oscilator circuit, such as a series capacitors and inductors. The reason this works is quartz will bend when a voltage is applied...so all you do is rapidly bend and unbend the quartz. I actually don't think the dimension of resonance will be too small...in fact i'm sorta worried it would be too big. Go over to radio shack and buy a piezoelectric transducer and put five volts on it...the transducer inside makes a pretty significant jump (We used to use these in reverse as kick drum triggers...the low voltage output from a rapid bend in the quartz would be used to trigger a drum brain...very very cheap compared to commercial triggers.) I would be more worried that the lens would jump so much as to distort the picture...but if the oscilation is at 1Mhz...i'm not sure this would be noticable...or if it would just look outright rediculous

Ignacio: Yeah your right...I'm not sure eactly what I was thinking when I said a 1Mhz tone lol. However, there is still the possibility of short wave radio interference and kooky effects it could have on your ccd's.

But the main question is still unanswered...would quartz make an acceptable GG? In my head I think it could...but the cyrstalline structure could be such that any refinement of it may make way too big of a grain. I'm wondering if anyone has experimented with this...or knows enough about quartz lenses to tell.

Thanks for all the input
Matt

November 7th, 2004, 10:29 PM	#1
Matt Champagne Major Player Join Date: Nov 2004 Location: New Iberia, LA Posts: 229	Quartz Aldu35mm Adaptor I asked this in another thread, but I thought maybe it might deserve its own thread. Can Quartz be used as the ground glass portion of something simular to the static Aldu25 adaptor. The reason to do this would be because you could use the piezoeletric properties of quartz to cause it to oscilate...probably with very little noise. And if I needed to grind it myself, could glass be used as the grinding or would you have to use a second piece of quartz to prevent scratching or something. To make it oscillate would be very simple. Just create an oscilator circuit to convert DC to simulated AC from a battery. Problem 1...it may create an audible tone around 1Mhz - 10Hhz. Problem 2...it may create a short wave radio signal which could mess with camera operation (though I kinda doubt it). If anyone would want to give it a go, this might be a descent source for quartz. http://www.2spi.com/catalog/ltmic/quartz.shtml It's a bit pricey and I'm just a poor college student...so I don't want to order and start testing this all out until I get at least some confirmation that quartz could be ground properly to do this with it. Matt

November 8th, 2004, 09:22 AM	#3
Ignacio Rodriguez Contributor Join Date: Sep 2003 Location: Santiago, Chile Posts: 932	At 1 MHz and way below it will not be audible. Most old school TV sets oscilate at 15 KHz (quite audible for most people under 60) and nobody seems to mind much. Anything over 25 KHz will not be audible to humans. Cat's and dogs might have trouble with it, so stay over 200 KHz if you can. __________________ Ignacio Rodríguez in the third world. @micronauta on Twitter. Main hardware: brain, eyes, hands.

November 8th, 2004, 04:51 PM	#4
Matt Champagne Major Player Join Date: Nov 2004 Location: New Iberia, LA Posts: 229	quartz BOB: To answer a few of the questions all at once, what you would need is a quartz lens made out of a single crystal attached to an oscilator circuit, such as a series capacitors and inductors. The reason this works is quartz will bend when a voltage is applied...so all you do is rapidly bend and unbend the quartz. I actually don't think the dimension of resonance will be too small...in fact i'm sorta worried it would be too big. Go over to radio shack and buy a piezoelectric transducer and put five volts on it...the transducer inside makes a pretty significant jump (We used to use these in reverse as kick drum triggers...the low voltage output from a rapid bend in the quartz would be used to trigger a drum brain...very very cheap compared to commercial triggers.) I would be more worried that the lens would jump so much as to distort the picture...but if the oscilation is at 1Mhz...i'm not sure this would be noticable...or if it would just look outright rediculous Ignacio: Yeah your right...I'm not sure eactly what I was thinking when I said a 1Mhz tone lol. However, there is still the possibility of short wave radio interference and kooky effects it could have on your ccd's. But the main question is still unanswered...would quartz make an acceptable GG? In my head I think it could...but the cyrstalline structure could be such that any refinement of it may make way too big of a grain. I'm wondering if anyone has experimented with this...or knows enough about quartz lenses to tell. Thanks for all the input Matt

November 8th, 2004, 02:16 AM	#2
Bob Hart Inner Circle Join Date: Dec 2003 Location: PERTH. W.A. AUSTRALIA. Posts: 4,476	On electronics I am totally dumb. If you take to your quartz to make it conform to a thin plate shape and roughen one surface for a reverse projection screen :- Do you destroy the integrity of the crystal and thus its ability to resonate? Don't you need a single whole crystal to make a resonant circuit? Does the crystal itself in resonating to an AC current not change size over its entire strucure? The magnitude of any resonant change in dimension might be so small as to be insufficient. My imagining is that it would have to be a humungous big crystal with the optical path through a tiny part of one end of it. Assuming the crystal can be found which is big enough to create enough groundglass movement within itself, what is its fundimental resonant frequency, pretty low, maybe too low not to be itself resolved by the camcorder as a visible movement. Handy to carry around. - Too thick to fit within the flange to focal plane?