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Old April 29th, 2006, 12:59 AM   #31
Barry Wan Kenobi
 
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I re-read that and agree with Andrew that the way I said it was confusing. I was referring to 10mm = 10mm, whether it's on a 35mm camera or a 16mm camera or whatever. I said it wrong and appreciate Andrew's clarification.

And yes, I think we'll have to see it in action to know exactly what it's doing. They said specifically no ground glass, right? So... I don't know what that means for the DOF characteristics.

Was there any talk of the c-mount adapter? Or has this one replaced the potential c-mount adapter?
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Old April 29th, 2006, 03:09 AM   #32
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The image on the screen "has" the DOF of the attached lens because the screen is placed where the film would be placed. And, I assume the image is the same size as it would be on film. Which raises a several questions.

1) There must be a downstream lens that focuses the image from the GG to the prisms and CCDs. Now if the GG image is the size of 16mm film frame -- then this lens would seem to need to reduce the image by 0.46X to get to the 1/3-inch CCDs. Which makes me think THIS is the lens the JVC rep. was talking about.

2) So perhaps he was wrong about no GG.

3) Since GG grain can be measured by an FFT. It is, in fact, noise. The finer the grain, the higher the noise frequency. The more uniform the grain, the more narrow the noise band.

The fact JVC is developing the adaptor and the camera gives them the option for new approaches. In theory, this noise can be "notched-out" by a notch filter in DSP.

Alternately, if the noise frequency is higher than image detail (the signal), then a very steep low-pass filter can remove it. This can be an optical filter or a DSP filter.

4) Reading reviews of several lenses, it appears these lenses produced a slightly "curved" image on the film plane. This works because 16mm film very slightly curves between perfs. So how does a flat GG deal with the fact that either the center or edges can be in focus -- not both. I assume the GG can be either set for center or edge focus -- or adjusted for either.
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Old April 29th, 2006, 08:41 AM   #33
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Quote:
Originally Posted by Steve Mullen
4) Reading reviews of several lenses, it appears these lenses produced a slightly "curved" image on the film plane. This works because 16mm film very slightly curves between perfs. So how does a flat GG deal with the fact that either the center or edges can be in focus -- not both. I assume the GG can be either set for center or edge focus -- or adjusted for either.
The Aaton "Ground Glass" is curved on one side to allow for this.
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Old April 29th, 2006, 10:16 AM   #34
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If you resize the apparent field of view of a lens optically through a magnifying lens, the depth of field becomes equivalent to whatever the new *effective* focal length of the lens is, not the focal length of the original lens. Believe me, a while back I thought it would be clever to try to shrink my depth of field by putting a wide angle adaptor on the end of my lens. I would then have to zoom in to get the same field of view, giving me a smaller depth of field, right? Err, well, wrong... At least I can shoot some nice wide-angle shots now. =D

This is why adaptors like the mini35 use ground glass. If you could just shrink the image optically and get the same depth of field, they would've done that and avoided all the hassles such as light loss that dealing with ground glass gives you.
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Old April 29th, 2006, 12:42 PM   #35
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Well New Life for my Arri BL16 Lens

Its been a while since we shot with the Arri BL16, mow the lens wil be in use again, so guys moral of the lesson dont throw away your old stuff. I have already spoken to JVC dubai, cant wait to get the adapter and shoot some TVC, with GYHD 100 and the lens thats the end of my M2 experiment or is it.
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Old April 29th, 2006, 03:34 PM   #36
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Here is a quick example of what can be purchased for use with the new PL adaptor

http://cgi.ebay.com/Set-of-6-super-f...QQcmdZViewItem

http://cgi.ebay.com/ANGENIEUX-COMPAC...QQcmdZViewItem
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Old April 29th, 2006, 04:08 PM   #37
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Quote:
Originally Posted by Yusuf Thakur
Its been a while since we shot with the Arri BL16, mow the lens wil be in use again, so guys moral of the lesson dont throw away your old stuff. I have already spoken to JVC dubai, cant wait to get the adapter and shoot some TVC, with GYHD 100 and the lens thats the end of my M2 experiment or is it.
The new adapter has PL mount though, not Arri BL mount. I'm sure a conversion could be done.


I was told at the JVC booth that the idea of the PL adapter is that the horizontal FOV on a 16mm camera would be maintained AS WELL AS depth of field. I was also told that there is NO GROUND GLASS like similar third party products.

So how is it done optically? We don't know because the unit being displayed at NAB was an empty glassless mock-up.
I have also been thinking about depth of field and the calculations based on acceptable circle of confusion values and I am now starting to doubt that a 16mm image reduced to 1/3" HD will possibly maintain the depth of field characteristics on a 16mm gate.

We simply won't know anything about this mysterious adapter until it is released.

Here's my photos of it:
http://www.timdashwood.com/.Pictures...HD200-PL_A.JPG
http://www.timdashwood.com/.Pictures...HD200-PL_B.JPG
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Old April 30th, 2006, 01:59 PM   #38
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Thanks Tim

[QUOTE=Tim Dashwood]The new adapter has PL mount though, not Arri BL mount. I'm sure a conversion could be done. We simply won't know anything about this mysterious adapter until it is released.

Lets see if this goes like Optex story and the nikon adapter, I just could not wait as I wanted to mount nikon lenses from day one even before I bought
the GYHD100. Got in touch with Zoerk, and rest as we say is history.
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Old April 30th, 2006, 02:27 PM   #39
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When is this going to be released? This sounds like a bit of a miracle if it works.
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