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-   -   Mini 35 Competing Unit for a Lot Less $ (https://www.dvinfo.net/forum/techniques-independent-production/10532-mini-35-competing-unit-lot-less.html)

Joseph George June 23rd, 2003 07:23 PM

Hi guys, I'm back from my trip. There is no vignetting. You use the GG in the film plane. There is no vignetting on film either. You vibrate the glass to the sides only. The image will not be perfect; you can claim it is a film look -- some of the grain. The vaibrations need very high frequency so the video frame sees always more than one spot. But we tried it and piezo drive does not work.

Cosmin Rotaru June 24th, 2003 02:43 AM

Whell, in film there is no vigneting but you're not interested in the light that passes throu the film...
Could you give me some info on the gg you use? Maybe the manufacturer? Thank you!

Jaime Roman June 24th, 2003 09:12 PM

Hey joseph,

Why a piezoelectric drive as opposed to a vibration motor? What would you consider a high frequency (rpm)?

Cosmin Rotaru June 25th, 2003 05:39 AM

Hi all,
This is my own attempt, my little experiment on this mini35 homemade stuff...

This is the 50mm lens I use. For this test the iris was wide open at 1.8. (quite a fast lens - very narrow DOF at this opening)

This is the fresnell I use. Is a book sign...

The little GG. I cut it from a fake CD. The kind of unusable look alike CDs that you find in bulk CD boxes. They're at the bottom and on top of the bulk, for protection.

The GG and fresnell makes a sandwich. There's about 2mm space between the two. If there's no space between them, the fresnell's rings becomes visible.

I use an old electric razor as a means for vibrating the GG/fresnell sandwich!

Here are all parts in an improvised homemade mini35 adapter. I'll have to do more experiments until I decide if it worth doing something stable and usable.

Now for the tests:

This is a pic using the camcorder's lens alone (canon XM2 - European PAL version)

Here's a pic using the homemade adapter with the GG not vibrating. Very grainy. I think I need a better GG.

This is a pic with the homemade adapter. The GG is vibrating. I also modified a little the color curves.

Here you can see a little demo clip (you need WMP9) that starts with a grainy look and than the GG starts vibrating and the grain almost disappears. I modified the color curves also, for the part were the GG vibrates. :)

Din anyone tried something else?

Chris Hurd June 25th, 2003 05:45 AM

Cosmin, these aren't loading for me. If you can send them to me by email, I'll be happy to put them on the DV Info server for easier access.

Cosmin Rotaru June 25th, 2003 05:51 AM

I don't know... I can open the pics but the video is totaly unaccesible...
I'll send you an e-mail Chris, if you can help me with this.

Cosmin Rotaru June 25th, 2003 06:02 AM

I've sent you the pics and the clip.


Chris Hurd June 25th, 2003 06:38 AM

See http://www.dvinfo.net/media/cosmin/ -- this should provide a clickable directory listing of these images and the video clip. It'll have to do until I can put a page together; I'm leaving momentarily for the L.A. Entertainment Technology World trade show.

Cosmin Rotaru June 25th, 2003 07:35 AM

Have fun there, Chris!
And thanks!

I have updated the links on the original post. I hope now they're working!


Joseph George June 25th, 2003 09:07 AM

Edmund Scientific sells ground glass. The piezo elements would make it a nice reliable design. The image stays o the GG. It does not go through the GG. Frequency? I would say as high as possible -- couple hundred Hz and up.

Zac Stein June 25th, 2003 09:33 AM

Not exactly quiet heh heh, looks cool though.


Cosmin Rotaru June 25th, 2003 09:35 AM

Hi Joseph,
have you seen my "setup"? You're probably doing it in some other way... In my setup the light has to go thru the GG. Some GGs would make smaller vigneting at the expense of loosing much of the light. If the GG is not that dense (it is more clear) it would transmit more of the light but with more vigneting. The fresnell always helps in the setup I'm testing...

Cosmin Rotaru June 25th, 2003 09:41 AM

Well, it is an electric razor, Zac! :)
My wife didn't like the noise either! (It was like 2 o'clock in the night when I finally pushed the button!) I think it vibrates at 50Hz. This is what we have here: 220V at 50Hz. So the ancient razor I think it goes 50 cycles/second!
I'll do more testing. I'm not going to use the shaver in a final setup, though. :)

(is it "razor" or "shaver"? - English is not my native language...)

Zac Stein June 25th, 2003 09:45 AM

They are called, electronic razors/shavers here... but I don't speak 'yank' so I am not sure what they call it. We already had quite a large discussion about flip flops.

I would love to see a schematic of this thing... i have a lot of parts sitting around, and am meeting with an engineer first thing next week, would be great to knock this thing together.


Cosmin Rotaru June 25th, 2003 10:13 AM

Hey, I thought the pic would be enough to see what I did!
Just ask what is not clear from the pic, ok? I'll be happy to answer your questions!

O! The lens I'm holding goes on the camcorders lens. As close as posible. So I could zoom al the way in to the GG and still focus. If I just bring the camcorder close to the GG (in macro), I'm to close to the fresnell and out of its focal point. Way out! So that's translated into a BIG vigneting problem!

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