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Old June 3rd, 2005, 08:51 AM   #1
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Any Luck using Century Anamorphic

Hello all.
I have followed this board for a while now. I'm on my third build of a static adapter and I'm trying to use a Century Precision Optics 16:9 adapter in front of my 55mm lens.

Lots of trouble focusing. I've read through the forums looking for answers, and found something about anamorphics having two different DOF's; one in the x axis and half of that in the y.

Has anyone had luck getting a sharp focus with a Century 16:9 adapter in front of a "35mm adapter". I've seen some pics in "hart" media folder that say they were shot with the same 16:9 adapter, but those images were not very sharp either.

The goal of course is to use all the pixels when shooting widescreen, but if the image is soft, it defeats the purpose. I get much more sharply focused image without the 16:9 lens, but I have to crop away a lot of my pixels to get widescreen. Not to mention that the 16:9 lens was $699 and doesnt seem to work for this application. Bummer.

If someone has a solution you would make my day.
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Old June 3rd, 2005, 11:41 AM   #2
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How about putting the 16:9 adapter on the camcorders lens (or mounted on the 35mm adapter right before the GG.) Than you only have to focus it once on the GG and put any lens on the 35mm adapter.

Last edited by Oscar Spierenburg; June 3rd, 2005 at 07:39 PM.
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Old June 3rd, 2005, 11:54 AM   #3
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Donnie,
I had "hand held" the anamorphic in front of a 1.4/35mm (on image converter, on Z1) a while ago, but only for a short time and as a curiosity only. It seem fine but I did not check it throughly. It seem fine though (or perhaps due to wide angle lens I had it on!) I will check it again against tighter lens as it seems to have application.
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Old June 6th, 2005, 09:16 AM   #4
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Thanks for the thoughts, I have the non-focusing 16:9 adapter model...

http://www.centuryoptics.com/products/dv/16x9/16x9.htm

If anyone else has made this setup work, I'd like to hear about it. Thank you.

camera - GG - Macro - 55mm lens - Century 16:9
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Old June 6th, 2005, 09:31 AM   #5
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Quote:
Originally Posted by Donnie Wagner
camera - GG - Macro - 55mm lens - Century 16:9
wouln't it be... camera - macro (if need be) - GG - SLR lens - 16:9?
(I did not hear yet of a macro betwen SLR and GG) mistake? or is that what you ment?
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Old June 6th, 2005, 09:33 AM   #6
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For what it's worth, I called Century to ask if the adapter would work with a Super 8 camera and was told a very definitive "no" by one of their techs. This seems similar to what you are trying to do.
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Old June 6th, 2005, 01:49 PM   #7
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I dont think these homemade adapters relate to super-8. It should be the same as using it with a 35mm SLR camera. I also called century and they said it should work fine for this appication, as long as the lens is no less than 37mm, and not more than 180mm.


The Macro is another issue. I think the macro belongs between the 35mm lens and the GG. But I'm sure there are several different oppinions on this. If anyone cares, I will put together my reasoning.
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Old June 6th, 2005, 02:05 PM   #8
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I am eager to learn the reasoning.
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Old June 6th, 2005, 03:32 PM   #9
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Just My Thoughts

On Macro's or Fresnel's...

with a simple "GG - 35mm lens" set-up-
The light from a 35mm lens is refracting trough the GG at different angles. The light in the center passes through efficiently, and the much of the light towards the outside edges gets reflected off. See this link for a good drawing...

http://acept.la.asu.edu/PiN/rdg/refr...raction2.shtml

A fresnel lens can be used as a "collimator" as seen in this drawing (drawing does not totally make sense, but you can get the idea) it straightens, or causes the light rays to become parallel to the center rays...

http://www.3dlens.com/

***If this fresnel is between the GG and the 35mm lens, it straightens the light just before it hits the GG. In theory, all the light rays should be traveling perpendicular to the GG, and parallel to the center rays. This gives more even transmittance from edge to center (which we see as even brightness)

***If the fresnel (or macro) is between the camera and the GG, it can only affect the light that has actually made it through the GG. The light that makes it through the GG will have a gradient of brighness from edge to middle.
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Old June 7th, 2005, 02:41 PM   #10
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Dan,
Did that make any sense? I havent discussed this with anyone before...
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Old June 7th, 2005, 03:01 PM   #11
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Quote:
Originally Posted by Donnie Wagner
If this fresnel is between the GG and the 35mm lens, it straightens the light just before it hits the GG
Yes, depending where the Fresnel is placed (how far from lens and how far to GG) and subject to its focal lenght (Fresnel's)
Quote:
Originally Posted by Donnie Wagner
If the fresnel (or macro) is between the camera and the GG, it can only affect the light that has actually made it through the GG. The light that makes it through the GG will have a gradient of brighness from edge to middle
First sentence: Yes but it will also affect the image (not only the light) Second sentence: therefore a Fresnel after GG would be useless (and that is why is never placed there..)
All SLR focusing screens have the Fresnel side towards the lens and the GG side towards the viewfinder (pentaprism or no in the system) They serve the intended purpose: to "brighten" the far corners of the image. How? They "steal" light and re-direct it towards GG. But they get it "first hand" not in an angle as the light would come from the lens there. Long focals can live better "whithout" due to their taking angles. Wides are notorious for vigneting (for the same matter)
BTW, Did you ever see a linear Fresnel? Where? what does it do?
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Old June 7th, 2005, 04:02 PM   #12
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Quote:
therefore a Fresnel after GG would be useless (and that is why is never placed there..)

Beattie says its fresnel screens can be used on either side...

http://www.intenscreen.com/pdf/INSTA...EW_CAMERAS.pdf

and you asked about a linear fresnel? I'm not farmiliar with the term. If you were referring to the fresnel being used to "collimate" light into a straight path, they can be convex or concave (depending on how the prism grooves are designed), and they can act as a collector or a collimator, depending on the design and which way the light is passing through them. Same lens can do both.
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Old June 7th, 2005, 05:41 PM   #13
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[QUOTE=Donnie Wagner]and you asked about a linear fresnel? I'm not farmiliar with the term. QUOTE]
From the page you posted:
http://www.3dlens.com/
>>>Types of Fresnel Lenses
Types of Fresnel lens: positive fresnel lens, negative fresnel lens, fresnel lens array, cylindrical fresnel lens, circular fresnel lens, linear fresnel lens, lenticular fresnel lens, diffraction fresnel, fresnel reflection, fresnel beamsplitter and fresnel prism.<<<<
It does not matter too much, but any LCD, TFT, screen is a linear Fresnel; the "big challange" (years ago) was the screen (60% of the laptop's price)
There are two vertical side tubes and yet the whole screen is even lit. Vertical stipes (smaller towards sides and "thicker" towards center obeying the square distance light loss law making the screen apear to be "even lit".
As for what matters to us regarding Fresnel orientation, I read Beattie's info but "their" purpose is different than "ours". They made it for eyes(viewing), we use it for lenses.....(videotaping).....
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