New Panamorph Lens Coming Soon - Page 3

Thanks for answering another of my noob questions. I know that everything I've asked has probably been discussed before, I just can't seem to hit on the right keywords in my searches to find the answers.

I do have another question. Because the room I'm planning is going to be used for video gaming room also, I'm trying to keep the throw short to allow for room for people to play XBOX kinect games without throwing their arms into the light path of the projector. In order to do that, right now I'm planning on using about 1/2 of the zoom on my projector (Viewsonic Pro8200). Approx 13' throw, 52" CIH screen. Will that cause an issue with an A-lens setup? I was thinking about it yesterday and for lack of a better way to explain it, if you use too much of the projectors zoom, can you run out optical area on your A-lens? (ie The height of the zoomed image coming out of the projector is too tall to 'fit' vertically through the A-lens?)

Yes you can. When the projector beam is too thick to fit wholly through the anamorphic lens, it is said to be "vignetted".

To get a start on figuring out whether the beam will be too thick to fit through the lens, you need to calculate Throw Ratio (TR), which is the ratio of Throw from the projector (T) to 16:9 Screen Width (W): TR = T/W.

As 16:9 Screen Width is 16/9 time 16:9 Screen Height (H) - or H=0.5625W - you can calculate Throw Ratio based on this height:
TR = T * 0.5625/H

Either will do. Sometimes height is used because, in a Constant Height system, using a Scope format screen, "16:9 screen width" is a somewhat abstract concept, but the height is always directly measurable.

The lower the Throw Ratio, the wider the beam, and the more likely that beam might vignette inside the anamorphic lens.

You need to consult your lens maker to see if their lens is wide enough for your application.

This will depend on

* Throw Ratio (as discussed),

* Projector type (DLP projectors typically have thicker beams for equivalent Throw Ratios than LCD or D-ILA projectors),and

* Mounting Offset (how far in front of the projector optics - including any lens recess - the anamorphic lens is physically mounted - the larger the Mounting Offset, the thicker the beam will be by the the time it reaches the lens).
Edited by Aussie Bob II - 12/5/12 at 2:07pm

Easiest way is to set your projector zoom to the hight of the image you want from your throw distance. Hold a white piece of paper in front of the projector lens. Measure the width of the image square that appear on the white paper. Consult the A-lens manufacturers measures specs and see if the width of your image square fits the entrance width of the A-lens.

Actually, I have been playing around with your curved screen spreadsheet and calculated a TR of 1.55 using a planned 13ft throw and 52" CIH

Will have to check with lens manufacturer regarding zoom compatibility, and I'll probably play around using the piece of paper techinque the OP suggested.

Regarding your spreadsheet, the lens company recommends a 2.40 AR if you have a short throw. Is there a way to modifty your spreadsheet to account for that when calculating screen curve/size? I know it's only going to be a few pixels either way, just figured I plan to do what the lens manufacturer suggests.

BTW, thanks for making the spreadsheet available. It's been a great help being able to play around with TR and height and see how it affects the screen measurements.

Since you are posting in this thread, I am assuming that you are evaluating the CineVista lens. Here are the aperture measurements:

3.3” wide x 2.08” high

This is pretty much the same aperture as the UH480 and DC1 in terms of width. In Panamorph's lab tests, it works with throw ratios down to about 1.3 with most projectors. There are other factors that can affect this, though, such as whether or not the projector itself has a recessed lens.

In our experience, people have been installing projectors in smaller and smaller rooms, which results in smaller throw ratios. The CineVista was designed with this in mind. Keep in mind, though, the smaller the throw ratio the more pincushion distortion you will have.

I suppose there is but, as you say, it's only a matter of a few mm.

The reason the "lens company"recommends a 2.40 AR is because at low throw ratios the differential geometric distortion (ratio of edge to centre distortion) gets bigger. This means the image gets wider compared to its height, so a 2.40 AR screen is almost mandatory, unless you go curved.

That's OK. It has its limitations, as I wrote it a long time ago, and didn't think of making it more flexible. I'd have to completely re-jig it now, and that's if I can remember how it works! The calculations there get pretty dense.

You can use GOAL SEEK to set the pincushion percentage you want by retaining screen height as a constant and allowing GOAL SEEK to vary throw. Or you can set your curvature at one of the standards (40' or 30') and tailor throw and/or screen height to fit it exactly so that pincushion is perfectly eliminated.

I have an in-house version of this now that I use for installers. They supply me with screen height, throw and height the projector is mounted above the center of the screen.

From that I can determine where the mounting holes for the CineSlide (if used) have to be mounted, the angle of tilt, whether the case of the lens will bump into the projector (and how to fix this), as well as the more traditional throw ratioand pincushion measurements.

The spreadsheet takes overlap into account, DOES tailor for 2.40 v. "Other" shaped screens, has a library of projector lens recesses to calculate beam size at the exit pupil of the lens and several other things that I've already forgotten about. It produces a .CSV format macro that I can feed into my optics software model to double check everything will work, and also to calculate MTF, distortion and suchlike.

From this I can virtually guarantee performance and make helpful suggestions to installers up ladders on how to best install their lens in the exact set-up they specify, in the minimum amount of time (which is "money",of course). It saves everyone trouble and grief and so far has turned out to be accurate to one or two millimetres slackness either way, which is about as good as you'd want. The installers love it.

If they have an iPhone, I can send dimensioned drawings to them in minutes, while they're still up that damn ladder.

But it's clunky to use, not really for commercial release, and only works with my stuff anyway.

I didn't see it listed on the Panamorph site.....will this lens work with a JVC RS-20 projector setup?

It's under the Products tab, then CineVista lens. Here is the direct link:

http://www.panamorph.com/cinevista/index.html

Yes, it will work with the RS20.

here's another n00b question.. Do I need this Cinevista lens to get 2.35.1 image on the Panasonic AE-8000 projector?

The Panasonic AE8000 has 2.35:1 "zoom memory" capabilities, so no, you don't necessarily "need" the CineVista lens. Of course, the ability to use zoom on the 8000 is limited by your throw ratio and how much lens shift you need for your installation, so I can't answer your question definitively. The CineVista will arguably offer you a better 2.35:1 experience than using the zoom, though, since using the CineVista allows you to use all 1920 x 1080 pixels for 2.35:1 content (vs. 1920 x 810 for zoom). This provides for a smoother and brighter picture than the zoom method is capable of. The zoom method also ends up just projecting the black bars onto the wall (along with 16:9 menus and subtitles), which can be quite distracting. I've attached our "How It Works" pdf that shows exactly how anamorphic lens systems work in a straightforward, easy to understand visual manner. Since the CineVista is a "fixed lens" system, all of the points regarding fixed lens systems in the brochure apply to it as well. How It Works Guide (2).pdf 3754k .pdf file

Hi ,

I'm fairly new to this area of home theater . I have a few questions , and if anybody could help me out would be greatly appreciated

Is this new CineVista lens compatible with a JVC X30 ?
Since its a 'fixed' lens , how does that affect 16x9 1.78:1 images on a 2.35:1 screen ? Does the picture look weird or stretched if its not a scope movie ?

I've looked at a lot of the pictures on this site from people's 2.35:1 set ups , and I have to say I am very eager to switch to this from my current 16x9 set up . I'm just worried about the 16x9 picture being displayed distorted on the 2.35:1 screen . If someone can just give me the basics that would be great . Thanks !


Jason

Jason, Look at the post above your's and download that PDF. It will help with answers to your questions.

Yes, compatible with the X30 and yes, the pdf will answer all

Ah thanks .

I guess I was under the impression that with the lens in place it would/could fill up the 2.35:1 screen with a 1.78:1 image . Technically true , the image looks a little distorted and if you use the 4:3 mode it corrects it but loses a little bit of screen size . I guess it comes down to what format you watch the most . When using the corrected 4:3 mode for the 16x9 image . Does the projector itself " black out " the sides of the screen that are not being used ?

Anyway , I think this CineVista lens could be a good entry point for me into this 2.35:1 world .

Yes, as those extra pixels are just shut off.

Another way you can fill the screen is to leave the vertical stretch on when watching 16:9. You will lose a little bit of the top and bottom of the 16:9 image, but the geometry will be correct.

Fuzzyturtle, read this tutorial. It should help.

Thanks for the help guys . 2.35:1 here I come ...

Just ordered my cinevista should be getting it next week. will review it in a new thread when i get.

Ok , so I am going about this a little backwards . But I got the CineVista lens and a new oppo BD player . Now I need the screen and some suggestions . My projector is 14 ft from where my 16x9 screen is now , so the 2.35:1 one will take its place , so I guess I need to know how big of a screen I can get away with . Bigger the better . I was looking at a 138' ( 54' H , 127'W ) . Is that too big ?

Thanks for the help

Can you mock up a screen and try it with your lens in place?

You can Start Here...

http://www.projectorcentral.com/projection-calculator-pro.cfm
Edited by foraye - 2/26/13 at 12:10pm

That is the same size I have. My lens don,t arrive till Friday. My 6020 zooms well at that size if that helps.

What brand of screen do you have ? How far back is your projector

The limitation here will mainly be the brightness of the projector you will be pairing with. Otherwise you are fine from a throw ratio and distance perspective. Most current projectors will handle that screen size without much difficulty.

Thanks for the response John , I have a JVC X30 . Would that be sufficient for the brightness needed for that size of screen ?

Would a throw ratio of 1.77 be too short for the Cinevista?

It should be. What screen material / gain?

1.6X the 16:9 screen width is usually the minimum. Would be helpful to know the rest of your specifics - throw distance, projector, screen size, etc.

Here are the specs on the CineVista lens:

• Range of focal distance from screen to projector: 8 - 18 feet (2.4 to 5.4 meters).

• Ratio of projector throw distance to screen height: 2.5 x screen height minimum installation distance. Optimal installation range of 3 to 3.5 times screen height. It is not recommended to place your projector further back than a throw ratio of 4.5 times screen height.

• Recommended projector mount: Chief Mount or the Omnimount 3N1-PJT

• The CineVista is designed to be used in a fixed configuration, where the lens remains in front of the projector at all times. (In our view, the best way to think of this is that a fixed lens changes the projector from 16:9 native to 2.35:1 native.) Changes in aspect ratio are handled by simply changing the scaling mode using the projector’s remote (anamorphic stretch for 2.35:1 material, 4:3 mode for 16:9 material). The CineVista can be also be removed for 16:9 material if desired.

Throw distance would be between 13'0 to 13'6", screen size would be 125" 2.35:1 (49" height), screen gain would be 1.0 to 1.2 depending on what screen I get, and projector would be either JVC X35 (or 55) or Panny 8000.