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This is an anamorphic lens for Panavision projection of 35mm. It was made in the 50-60's time period I think.


35mm Panavision prints have about twice the anamorphic correction that is needed for DVD for example (i.e., for correcting 4X3 to 16X9). So it won't work.


There were some adjustable lenses I remember from Superscope that might have had enough range to perhaps work with HT. I wonder if anyone has tried them.

 

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The German website clearly states that they are using it for DVD...


YXY and a HTPC could be set up for the over correction... From my quick scan of the page I gather that full panel can equate to 2.35:1 (the M J Fox example) but also with a prism arrangement such as this what is to stop anyone adjusting the angle of the second prism to increase the compression... If you look at the images of the lens itself it appears as if this is the case so...


This would be a variable compression anamorphic system and with YxY you could have full panel 2.35, 1.85 etc etc... This I like...

<I have just run this through the wonders of Babelfish and yep this what they are saying>


Also they are saying that the only other comparable product is the ISCO system and that there is no prism system that is currently being made, sold, or marketed !!!


As this clearly explains how I assume the Pannie will be working (I was unsure how they would be arranging / utilizing the prism's... it begs the question why is the Pannie not being made with variable angle and stops for 1.85 and 2.35 ??? I assume that the removal of the first prism in the light path will be what is allowing the Pannie to have full 4:3 and why it gets its 'downshift'...



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HTPC without using windows... GUI Front Ends for Home Theater
 

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The simple prism system of the Panatar system is fine for the very long throw distances of full scale movie theaters (for which it was intended) because the light from any point on the film/panel/tube coming out of the projection lens is mutually parallel (collimated). As soon as you get inside of maybe 50 feet the image will become aberrated and will therefore require correction. The other issue is that for a given prism set designed for anamorphic manipulation there is an optimum configuration to minimize the color separation in the image. Consequently, a variable aspect ratio system reliant on a change in prism angles will compromize image quality at one selected ratio in favor of a best overall quality over the range of ratios.


Phreddy, the Panamorph "downshift" to 4:3 is actually simpler in that it is on a rail to move it out of the way altogether.


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Shawn Kelly

Cygnus Imaging
www.cgns.com


[This message has been edited by Shawn Kelly (edited 05-05-2001).]
 

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OK the plot thickens...


After getting a bit fired up on this variable prism arrangement I decided to check out anamorphic prism lenses a bit more carefully... a troll on over to ebay threw up loads of anamorphic lenses (Eiki projectors seem well covered) but nothing prism based but this page lists four variable prism devices that do exactly what we are looking for in the panamorph (albeit with probably more complexity and drawbacks)...


...Then to top it all of I find one for sale for peanuts !! I imagine shipping is going to be about twice the cost I may end up paying for then lens... I will keep people updated... I am checking aperture for compatibility with projector and I will have the headache of making a mounting but....


A 2.35 anamorphic prism attachment for less that I spend to tank my car ?!?!?


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EDIT Our posts crossed each other... Ohh well life is never that simple is it ??? I am still keen on the Pannie but part of my enthusiasm was the asumption that this was the same innards as the Pannie is using... Anyway at the moment I an still going to check for curisity value as I am really talking $50 asking !!!


[This message has been edited by Phat Phreddy (edited 05-05-2001).]


[This message has been edited by Phat Phreddy (edited 05-05-2001).]
 

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I am using a current model 235:1 scope lens from Isco that is designed for the newer shorter throw theaters with stadium seating and I am using this with my Seleco 800x600 dlp and a 235:1 dvd projected full panel through this lens is the best you will see.

It is that good. A huge improvement.


I will be designing a lens turret to swap between my 235 lens and any one of the 16x9 anamorphic lens for constant full panel use.


My lens gives me perfect focus from corner to corner with great contrast.

I will take some pics this weekend and put them online.


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Thanks Very Much!


Alan Gouger

AV Science
www.avscience.com


[This message has been edited by Alan Gouger (edited 05-05-2001).]
 

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Alan

Are you going to use the Isco2 lens on your turret ? What scaler are you using ? Have you tried the lens on the Transvision ?

I am very interested in this subject. A 2:35 screen, "now thats HT".

I am getting the Panamorph for my Transvision but a 2:35/1:78/1:33 system using the whole 1024x768 is a good prospect for HT nivaria (my addiction). Fixed hight Variable width.

WOW


DavidW



[This message has been edited by David Wallis (edited 05-05-2001).]
 

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Phreddy, i also searched on ebay some days ago, but i found just round lenses, no one of them seemed suitable for a short throw HT purpose.

Anyway i think it would in some way be possible to produce a new one from a good optic laboratory, i would really like to have a Panamorph when shipped, but i find the price prohibitive.


bye



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dubmaster
 

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David


I reason im using this lens with the Seleco is because it has a long throw lens and the image exiting the lens is small enough to allow the use of the

35mm anamorphic adaptor.

The Dwin uses a shorter throw so the image is to large but I bought a replacement lens for my Dwin from Isco. It is a long throw so I tried this the other day and it looked great as well.




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Thanks Very Much!


Alan Gouger

AV Science
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Well ain't life a PITA sometimes... after being on sale for (apparently months) interest appeared 4 days ago and the cheque came in yesterday (same day as my email) so that Super Panatar was sold... $50 !!!


But some heavy trawling yesterday evening has turned up two other variable prism anamorphic attachments that may / may not work in a HT arrangement... I am attempting to find out sizing etc etc...


The reason I am heavily interested in this idea (apart from obvious cost benefits) is the benefit of variable compression... I understand that having a variable compression system has a compromise over a fixed (perfect) arrangement but cannot understand why this has an effect in one prism arrangement and not another (Shaun ??? color separation ??) I guess that why I am not in the lens business http://www.avsforum.com/ubb/wink.gif .. I have now exchanged emails with two people who have used this setup and both claim 'stunning' results with 2.35 compression (and I can imagine why !!)...


What I am shooting for here is to hack apart one of these puppies and try and rig an electronic control system.. A friend has a fairly well equipped engineering workshop (and skills) and if I could rig that slider up to a large cog and control that cog accurately enough with a stepper motor and small cog.. I could control the stepper motor with serial (simple) or go the whole hog and use X10 !!! I am not suggesting that this would beat the Pannie's outright performance but the idea of a single IR keypress.. being captured by Girder on the HTPC... To start a Macro event that Launches YxY at the correct 'stretch'... and fires the commands to set the lens to the correct 'squeeze' really does keep me awake at night (well last night anyway http://www.avsforum.com/ubb/eek.gif ).. As I do get over enthusiastic could someone point out any drawbacks to this idea ?? At the cost of these items second hand (who but us would want them) I dont really care if it doesn't work.. It will keep me out of trouble for a while !!!!


Alan pretty please... Pictures of this ISCO turret !!! I am drooling at the prospect...


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One thing about these variable anamorphic lenses, they are light hogs, they eat a lot of light, some are yellow/brown, and they are all made for long throws. Under 70feet nothing is sharp. Longer throws work better. The shortest focus possible is usually around 75 feet with a special diopter on the front - lenses without it are totally worthless - dioper was made for different throws and is marked so. The front 'flat glass' is actually a diopter. Since these lenses have no focus(actually astigmatism) adjustment they are useless for short throws. Otherwise they are nice piece of glass and metal, heavy too.

I went through all of the above a year or so ago, almost bought one for 200$ on ebay, but finally find a really knowledgeable person with cinema equipment who explained it all to me. B&L anamorphics are the best for short throws and can be bought for 50-100$ easily, a little modification with lathe and they can focus down to 12feet. You will also need an primary lens for this, as the original projector lenses are usually too wide and wont 'fit' in the anamorphic without vignetting. I am experimenting with a few of these and some primary lenses I got. Of course I will have to remove the original lens from the projector... will let you all know about the problems I will encounter..


Of course nothing can beat a nice mint Schneider Lens as the one Alan got for really cheap considering how much a new one goes for http://www.avsforum.com/ubb/wink.gif



[This message has been edited by J.F (edited 05-07-2001).]
 

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Late comment from a newbie:


Just wondering if the prism system can be used in the projector where the light path is parallel.


One of the two problems mentioned about using prisms is the fact that the light exiting the final lens is not parallel unless the final lens is of the long throw type (which makes it close to parallel). (The other is that colors break up going through a prism.)


I assume that somewhere in the light path, the light will be travelling in parallel. If that were the case, then the prism can be introduced at that point.


If the projector is a 1 chip DLP, and if the color shift is significant enough, a computer can be used to compensate by shifting one (or two) of the colors by 1 pixel in the direction of the shift.


Just a logic exercise, but am I way off on this?
 
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