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Old April 30th, 2007, 01:33 AM   #1
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DIY Adapter ghosting problem. Help.

I have developed my own DIY HD ready adapter. Using Canon EE-S screen as GG. And SGPro R3 Achromat.
But Some of the shots have a ghosting effect at the edge area. Is that a problem of the EE-S screen? The matte side of the screen facing the camcorder lens right now. Is this the reason causing the ghosting?
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Old April 30th, 2007, 01:36 AM   #2
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I'm using the adapter with a Sony HVR V1P.
I use my own adapter to shoot my Final Year Project in a film school.
but there are still some technical problems I have to solve.
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Old May 2nd, 2007, 01:15 PM   #3
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Help me! The ghosting problem is annoying.
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Old May 2nd, 2007, 01:35 PM   #4
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From your grabs, I dont see any ghosting problem that you are refering to. can you highlight the problem a little better?
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Old May 2nd, 2007, 03:05 PM   #5
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I think I can see this only on one picture at the right upper corner. Try to put sun behind your subject in a corner and you will probably see those ghosts of light. Reverse your gg, matte to the SLR lens. This is known problem as I can remember. Toenis has said abot that alot. But your picture is superb!! Good work anyway. I am on your trail also, and couple of others too...
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Old May 4th, 2007, 01:31 PM   #6
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But in some certain shots. The edge ghosting problem come out. And it is really annoying. Is that a problem of Canon focusing screen? Damn I bought many of them. And also a hotspot problem.
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Old May 4th, 2007, 01:49 PM   #7
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Hi Lau Ho Ming,

it looks like you have the ee-s mounted wrong.

Attention!
For vibrating adapters the Canon Ee-S / Ee-A must be mounted this way:

matte side faces the camcorder lens!
fresnel side faces the (SLR) 35mm lens
This avoids the hotspot.

Do you have something else in your adapter achromats, condenser...
that can produce this ghosting effect?
What SLR lens do you use?
Did you fixed the Ee-S at right focal flange distance?

best regards
Daniel

http://www.jetsetmodels.info/news.htm
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Old May 4th, 2007, 02:25 PM   #8
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Yes. At that shooting day. The EE-s screen has the matte side facing the camcording and the shiny side facing the SLR lens.
And I was using a Nikon 50mm f1.4.
The achromat is SGPro one so it is less likely the origin of problem.
Maybe the EE-S screen is not suitable for HD? Should I change the ground glass? I don't have a condenser.
I can't find a better GG than the EE-S right now.
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Old May 4th, 2007, 04:05 PM   #9
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On B&H there is a note for Ee-S, that it differs from Ee-A by the fact that it can come into focus in less graduations than an Ee-A, and at the price of f-Stops consumed. The configuration of its grain maybe not the most suitable for the lens configuration. Although many others on this site have used it in 35mm projects.

I am going to purchase Ee-A myself, unless someone else has already tried the two and says it's a bad idea.
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Old May 4th, 2007, 04:37 PM   #10
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I tried both of them. To summarise. I would say:
1.)EE-S has nicer bokeh than EE-A screen at wide open aperture e.g. look at f1.jpg
2.)EE-S is darker than EE-A only when you need to stop down beyond f2.8.
3.)EE-A has a weird vignette especially when you stop down no matter how hard I try to solve it.

I used both of them. I can't see the difference of focusing...

Back to the topic of ee-s screen.
Maybe I should grind my own glass for my adapter?
Is it a good idea to grind the nikon focusing screen condenser glass like what Snodart did? How is the performance of sharpness and brightness of that grinded glass compared to stock focusing screen in a vibrating design?
But to me the EE-S is ultimately clean and sharp...but there are some weird artifact.
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Old May 5th, 2007, 05:47 AM   #11
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I have been trying to see the fault in the image, now I can.

I think you may be trying to get too big a picture off the groundglass which will be causing the hot spot. A groundglass which is too transparent will make this happen too. It has been a reported issue with the Canon screen.

I understand the Canon screens have a fresnel patternon the shiny side. If I am wrong ignore everything I say here.

If you have more than one Canon screen, try putting two together with the groundglass finish face-to-face. You will the have in effect this path :-

Subject >> SLR lens >> fresnel (condenser) >> groundglass|groundglass >> fresnel (condenser) >> Wayne Kinney's achromat >> camcorder.

If you are moving or vibrating a Canon screen with includes a fresnel (condenser) function, you may not get good optical performance outwards from the centre because the fresnel (condenser) optical centre axis is being moved off alignment.

Any defect will likely occur towards the corners or edges where the light bending effect is at its greatest. This may be where your peripheral radial blur (what you call ghosting) is coming from.

"Ghosting" is the maybe wrong word to describe the problem. In groundglass talk it has come to be the word used for a fuzzy outline around a sharp bright object which becomes a problem when the groundglass is too transparent.

Your problem looks like it is optical and moving the fresnel (condenser) elements may be the cause. The fresnel elements may be doing this on their own.

Shoot some images with the motor switched on and with the motor switched off. If there are changes, you'll know this is the cause.

Zooming in closer on the groundglass for a smaller image area, may fix the hotspot with a static groundglass but with your moving groundglass, the edge defect or ghosting as you call it may remain.

I am really only guessing here so don't pay too much notice to my comments.

Don't grind your screens. Face-to-face will increase their opacity and help deal with the hotspot. Make sure they are both firmly locked together. Otherwise if one moves against the other there will be scratches or polishing of the groundglass texture which will cause marks.

If the movement is the cause of the problem, there will be no cure unless you can separate the groundglass screens from the fresnel optics. If they are made from one piece of glass then you cannot do this.

Last edited by Bob Hart; May 5th, 2007 at 06:06 AM. Reason: errors
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Old July 22nd, 2007, 01:33 PM   #12
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It seems like it doesn't matter which side is facing the camcorder as I'm also getting the same wierd ghosting effect on both sides.

I've also noticed that sometimes small and bright out-of-focus points, are being "smeared" into the center of the screen. I think the fresnel is causing this, and there's no way around it.

I'm gonna try what snodart did, and grind my own nikon f3 condenser lens.

I know it's a pretty old thread, I just wanted to share my observations.
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Old July 22nd, 2007, 11:13 PM   #13
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Ghosting images

I just finished my 35mm adapter and is hooked up to a JVC HD100u. Looking at your examples the ghosting is on the outside from center, near the edges. And also near the edge of the frame are a little dark. That tells me that you need to zoom in a little more on your image plate. Your at the edge of the front lens focal point. If you were to see that in a SLR camera that part of the light would not hit the film. I hope this helps.
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Old July 23rd, 2007, 06:35 AM   #14
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Yes, you could zoom in more to get rid of the ghosting, but wouldn't that for example make my 50mm lens act like a 60mm ( depending on how much I have to zoom in )?

Are you saying that the target size is actually smaller than 36x24mm?
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Old July 23rd, 2007, 08:10 AM   #15
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If you are going to be faithful to the 35mm motion picture film frame, its 24mm x 18mm.
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