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Old May 26th, 2004, 07:32 PM   #856
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Obin - A few questions

Obin-
1)Are you using the DVX100 or the DVX100A? Whats your Z#&F#?
2)Whats the focal length and diameter of the PCX lens you are using?
3)Could you measure and post the measurement for the gap between your PCX and the very front of the DVX100's glass lens?
4)Sounds like there is a gap between your GG and the PCX lens. Could you measure and post that distance as well.
5)Lastly please post a picture of your adapter.

With all of these questions answered it will be clear to everyone why and how your design works. Thanks.

-Brett Erskine
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Old May 26th, 2004, 07:41 PM   #857
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Also it looks like you have some heavy light fall off on the edges of your frame. Did you check to see that your camera is able to zoom in and focus on a 36mm X 24mm frame size area of the GG? If it is then the problem is that your PCX isnt fully correcting for the light fall off. You would need to get a PCX lens with a slightly shorter focal length to fix that. BTW how did you go about rotating the GG?

-Brett Erskine
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Old May 26th, 2004, 09:45 PM   #858
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one thing great about the spinning glass(cd) is that every frame has a new pattern of grain because it is spinning so I never have the effect of having a net infront of the screen
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Old May 26th, 2004, 09:51 PM   #859
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pcx is VERY VERY close to dvx lens I took the square lens plstic protector off the camera so that the pcx almost touches the dvx lens and the gg is I would say 5-10mm away from the pcx this way it enlarges the gg a bit. soooo get your pcx VERY close to camera lens and keep the gg a bit back and it works! I may end up using a +4 diopter to get that bit of balck off the screen in the corners but I only see that at full WIDE on the canon 28-135 zoom
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Old May 26th, 2004, 09:54 PM   #860
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how can I get a PL mount for this unit? I want to get old cine lenses for the unit
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Old May 26th, 2004, 10:14 PM   #861
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Lens: PCX, Dia: 59.70, Focal: 62,

and

Lens: PCX, Dia: 52.60, Focal: 80, Coated

is what I bought I used the focal 60 lens the focal80 had a hotspot
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Old May 26th, 2004, 10:14 PM   #862
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odin's technique

I have a PCX that I'm usingin instead of the two +10 (crappy) macros I bought off of Ebay and it appears to work as Obin says. I just can't seem to figure out a way to secure the PCX to the front of the DVX. It's a piece of glass, dia: 52.60mm Focal: 80mm. The distance that I have the flat side of the PCX from the DVX lens is the exact distance if you just rest the flat side of the PCX on the little plastic piece that's screwed on in front of the lens. THen the distace that seems to work for focusing on the GG is is to place the GG approx 13 to 15mm from the cameras 72mm filter threads. I have a quantray and tiffen 72m filter ring in between the camera and GG (which is one of those crappy macros I mentions with the flat side ground). I put a 35mm slide onto the GG to measure the areas that you can focus on at that distance and it appears to be between 34 and 36mm widthwise. My DVX focus is at 00 and my Zoom is 60. As soon as I can figure out a way to secure the piece of glass to that plastic piece, I can give you much more exact measurements... but the tests I've done seems to say these are very close.

John
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Old May 26th, 2004, 10:22 PM   #863
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I have the PCX flat side AWAY from the camera lens facing the GG...john why do you have it the other way?? how can that work?
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Old May 26th, 2004, 10:24 PM   #864
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thinking about dropping the PL idea and staying with the canon mount...I see a set of 28-80mm and 70-300mm Tamaron lenses on the net...any feedback good/bad on them? why would I NOT want to set down $180 for the set brand new?
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Old May 26th, 2004, 10:29 PM   #865
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does anyone have an easy way to flip the image BEFORE it hits the camera lens? I got this far...can't be too much harder can it?
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Old May 26th, 2004, 10:43 PM   #866
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PCX

Obin,

When you first posted today I dug around for those lenses I purchased a while back and started playing around. Putting the 52.60/80 flatside towards the DVX and resting on the plastic piece works perfectly for me. No hotspot, and no distortion. RIght now I'm just using double stick tpe to hold the lens on but I know that won't hold for long term use.

John
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Old May 26th, 2004, 10:47 PM   #867
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odd that did not work at all for me...it was all warped when looked at on a monitor...found what we all need to buy for our poor focus pullers using the 35mm lenses:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=180&item=5700645539&rd=1
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Old May 26th, 2004, 11:36 PM   #868
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Flipping the image upright in the optical path is not all that hard. It is however a costly exercise compared to making the Agus/Aldu alone.

You need two right-angle prisms with enough length on the hypotenuse face to accommodate two full frames of your groundglass image. To be safe you need 40mm prisms which give you about 52mm on the hypotenuse face which gives you enough for a standard academy aperture frame. For a 35mm still camera frame you might need to go to 50mm prisms.

These prisms are arranged in 90 degree opposition to each other as in a prismatic binocular or telescope ( porro prisms ). Image in is inverted. Image out is erected and the right way around.

The prisms are costly, heavy, have to be mounted and aligned precisely in a way which does not injure them through local pressures, shock loadings surface contamination or movement.
Surface coated mirrors are a less heavy alternative but also require the same precision and care.

A suits-all zoom-through optical path is less likely to evolve than for the Agus/Aldu adaptors themselves which are relatively simple.

The difficulty experienced in catering for the 72mm lens front-end camcorders illustrates the likely difficulties with a much more complex optical path.

(For small camcorders, the smaller CD-R disks spinning at a faster rate or small fixed filter/groundglasses would be more in keeping with their light wieght and user-friendliness.)

For image erecting, small 37mm front-end handicams might get away with a 30mm prism/mirror pair. A 40mm prism/mirror pair seems to suit the PD150/VX2000 camera family and possibly other camcorders with 52mm front lens diameters (filter attachment is 58mm, not the front lens element).

Whatever you use, the Aldu35 adaptors will no longer be a simple self-centering screw and glue affair because it will have a dog-leg shape.

Likewise for the Agus35 which will likely have to lose the CD-R case which was the original attraction because of its low cost and simplicity.

For the sake of erecting the image into the camcorder, which we can correct in post, there may be an extra penalty of furthur definition and light loss. Do we really want to go there?

I do but then I am possibly a glutton for punishment. When I have my arrangement sorted I will advise. My initial thoughts are to use fine-grained craftwood to hold the prisms, rather than metal because of the wood's cushioning effect and easy workability. There's lots of cutting an shaping to do. For mirrors a folded sheetmetal arrangement would work but for prisms it would not.

Good luck.
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Old May 27th, 2004, 01:06 AM   #869
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ouch! maybe post will have to do...OR shoot upside down ;)
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Old May 27th, 2004, 01:12 AM   #870
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Has anyone here tried using an Aspheric PCX lens as a condenser? I'm curious about the quality of one of those and if it beats a spherical PCX.
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