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post #31 of 89 Old 08-26-2014, 11:09 AM - Thread Starter
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that 2.40 AR Star Wars image really got to me - so I tested out the idea of a "convertible screen" i.e. instead of masking - ADDING screen for the 2.40 stuff - and I have to say that I was pretty shocked that it wasn't that bad. My idea being, starting with a 16x9 pull down screen (as 90-95% of what I watch is 16x9) and adding a fabric to the side to turn the screen into 2.40 AR when I watch movies
I have a SeymourAV XD CenterStage Screen, and in addition I have an addition 8x10 piece of the screen material. So I had someone hold the materal on the edge where border currently is - and it was pretty good, the "line" wasn't very pronounced at all - and (at least for a few minute test) I didn't find it distracting.
Soooo my idea is
  1. being that the viewable area on the screen is 51x90- order a 51x32 piece (plus extra for the border)
  2. sew some good velcro to the current border and ditto to the back of this screen piece
  3. Add additional black border material to the top of the addition, so it can velcro to the bottom of the ceiling (also black)
  4. and for the bottom (put a 31" rod for taugtness)
  5. And when I switch from 16x9 to 2.40
Questions:
  • What do you think overall - ideas welcome?
  • With that I'd also get an anamorphic lens- should I get a vertical compression (VC) or horizontal expansion (HE). When I set my projector to letterbox mode - it squeezes the sides of the image - does that mean that I need a HE - or does VC also work?
  • Currently available (used prices) are a ~$200 HE hometheaterboys (HTB) lens or $500 Panamorph FVX200- what are your opinions - $200 is more my price range (as I need to get surround speakers so the little extra $$ is welcome) - but if there's a truly pronounced difference worthy of the price - I'd go for it. What do you think
  • Lastly - which AR are most movies nowadays in 2.40 or 2.35 - i.e. how should I set up the screen?

Last edited by cgott42; 08-26-2014 at 01:14 PM.
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post #32 of 89 Old 08-26-2014, 12:24 PM
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Quote:
Originally Posted by cgott42 View Post
that 2.40 AR Star Wars image really got to me - so I tested out the idea of a "convertible screen" - and I have to say that I was pretty shocked that it wasn't that bad. My idea being, starting with a 16x9 pull down screen (as 90-95% of what I watch is 16x9) and adding a fabric to the end to turn the screen into 2.40 AR.
I have a SeymourAV XD CenterStage Screen, and in addition I have an addition 8x10 piece of the screen material. So I had someone hold the materal on the edge where border currently is - and it was pretty good, the "line" wasn't very pronounced at all - and (at least for a few minute test) I didn't find it distracting.
Soooo my idea is
  1. being that the viewable area on the screen is 51x90- order a 51x32 piece (plus extra for the border)
  2. sew some good velcro to the current border and ditto to the back of this screen piece
  3. Add additional black border material to the top of the addition, so it can velcro to the bottom of the ceiling (also black)
  4. and for the bottom (put a 31" rod for taugtness)
  5. And when I switch from 16x9 to 2.40
Questions:
  • What do you think overall - ideas welcome?
  • With that I'd also get an anamorphic lens- should I get a vertical compression (VC) or horizontal expansion (HE). When I set my projector to letterbox mode - it squeezes the sides of the image - does that mean that I need a HE - or does VC also work?
  • Currently available (used prices) are a ~$200 HE hometheaterboys (HTB) lens or $500 Panamorph FVX200- what are your opinions - $200 is more my price range (as I need to get surround speakers so the little extra $$ is welcome) - but if there's a truly pronounced difference worthy of the price - I'd go for it. What do you think
  • Lastly - which AR are most movies nowadays in 2.40 or 2.35 - i.e. how should I set up the screen?
Masking your pulldown 16:9 screen for 2.35:1 is a very good solution. Without moving to a 2.35:1 screen I don't think a lens would be needed or worth it. The main benefit from a lens would be extra brightness and if you aren't looking for that it wouldn't be worth the cost in my opinion. That and using a HE lens would mean zooming the image. Masking will give illusion of a scope screen and help perceived contrast. Which is an inexpensive win in my book.

2.35 vs. 2.40 isn't much difference. If you aren't bothered by a small amount of overscan on the screen border both will fit perfectly. If you size it exactly for 2.35:1 there will be a small sliver of black on the top and bottom of the 2.40:1 image. I personally just overscan the image a smidge (maybe an inch on either side) and both look perfect.


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post #33 of 89 Old 08-26-2014, 01:17 PM - Thread Starter
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Quote:
Originally Posted by jeahrens View Post
Masking your pulldown 16:9 screen for 2.35:1 is a very good solution. Without moving to a 2.35:1 screen I don't think a lens would be needed or worth it. The main benefit from a lens would be extra brightness and if you aren't looking for that it wouldn't be worth the cost in my opinion. That and using a HE lens would mean zooming the image. Masking will give illusion of a scope screen and help perceived contrast. Which is an inexpensive win in my book.

2.35 vs. 2.40 isn't much difference. If you aren't bothered by a small amount of overscan on the screen border both will fit perfectly. If you size it exactly for 2.35:1 there will be a small sliver of black on the top and bottom of the 2.40:1 image. I personally just overscan the image a smidge (maybe an inch on either side) and both look perfect.
Sorry, I wasn't clear in my post - my ideas is to ADD screen , instead of masking it. i.e. leave the 16x9 intact, and then when I want to watch 2.40 AR movies - add a piece of the screen material (with border around it). I'm thinking of attaching via velcro to the existing side border, and to the ceiling, and putting a bar on the bottom for weight/tautness
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post #34 of 89 Old 08-26-2014, 01:58 PM
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Quote:
Originally Posted by cgott42 View Post
Sorry, I wasn't clear in my post - my ideas is to ADD screen , instead of masking it. i.e. leave the 16x9 intact, and then when I want to watch 2.40 AR movies - add a piece of the screen material (with border around it). I'm thinking of attaching via velcro to the existing side border, and to the ceiling, and putting a bar on the bottom for weight/tautness
Ahh got it. If you're extending the screen for scope then a horizontal expansion lens, like the HTB, would do the trick. I think you'll be very pleased with that setup. Be sure and post pictures if you go that route. I don't think I have seen or heard of anyone adding scope "winglets" to a 16:9 screen. No reason why it wouldn't work as long as the seam can be made not to distract.

To answer your earlier question, movies are released about 50-50 2.35:1/1.85:1.

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post #35 of 89 Old 08-26-2014, 02:16 PM - Thread Starter
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thanks - would the Panamorph fvx200 work in my setup - and how much of a quality difference is there between it and the HTB lens? (the MSRP is more than double)
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post #36 of 89 Old 08-26-2014, 02:25 PM
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A couple of points:

While the aspect ratio of movies released is about 50 / 50 in terms of aspect ratio, when you look at the top grossing (i.e., most popular films), the percentage changes to about 75% in 2.35:1 / 2.40:1. Check your own personal collection and see how they shake out.

Jeahrens is correct - don't worry about the difference between 2.35:1 vs. 2.40:1. The transfers themselves are all over the place when it comes to aspect ratio. Zoom a little into the surround and you are set.

An HTB lens has considerably more chromatic aberration than the FVX200, plus is not astigmatism corrected. With the FVX200 you have less than a pixel's worth chromatic aberration at the top and bottom extremes, with the HTB you have almost 3 pixels width CA at the left and right. If you had an LCOS or LCD projector that had color correction, you could dial this out. DLP models like the BenQ don't have color correction so there is no way to get rid of the aberration. While you can't dial out the aberration on the FVX200 either, it has less than 1/3 the CA of the HTB. Like I mentioned, it is less than one pixel at the extremes and almost impossible to see with any type of video content you choose to throw at it.

RE: astigmatism. The FVX200 is fully astigmatism corrected, which means that focus is corrected in both the vertical and horizontal. The HTB lens has no astigmatism correction, so sharp focus in one plane means soft focus in the other.

In theory and in practice, a vertical compression lens actually will outperform any horizontal expansion lens in terms of sharpness and brightness (compressing light is always more efficient that expanding it). This is even true when comparing the FVX200 to Panamorph's top of the line DC1, at more than three times the price (new, that is). There ARE complications, though. Since a compression lens makes the image shorter rather than wider, you will need to zoom the projector along with moving the lens into place in order to fill your larger screen (unless you want to leave the lens in place all the time, but as pointed out earlier, that means lower resolution 16:9 content). The other "complication" is that vertical compression lenses create barrel distortion instead of pincushion, so you should never pair them with a curved screen. Since you are going with a flat pull-down, that really should not make any difference.

I post all of this because many people are confused as to how vertical compression lenses work, and think that they are inferior to their horizontal expansion brethren. They are actually superior in most ways, other than ease of use.

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post #37 of 89 Old 08-26-2014, 02:29 PM
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Quote:
Originally Posted by cgott42 View Post
  • What do you think overall - ideas welcome?

Honestly, I think you should just get a scope screen.


Quote:

  • With that I'd also get an anamorphic lens- should I get a vertical compression (VC) or horizontal expansion (HE). When I set my projector to letterbox mode - it squeezes the sides of the image - does that mean that I need a HE - or does VC also work?
Both work fine, but they have different purposes. They work because the resulting shape is the same either way. The difference is a VC lens makes the image smaller vertically (ie Vertical Compression), where as an HE lens makes it larger horizontally (Horizontal Expansion).



Since you have a "fixed" height but want a wider image, you want an HE lens. Now a VC could work, but it means you either have to zoom the projector adjust/refocus/etc every time you move the lens, or you have to zoom and leave the lens in place all the time.


Quote:

  • Currently available (used prices) are a ~$200 HE hometheaterboys (HTB) lens or $500 Panamorph FVX200- what are your opinions - $200 is more my price range (as I need to get surround speakers so the little extra $$ is welcome) - but if there's a truly pronounced difference worthy of the price - I'd go for it. What do you think
I'm not sure either option is better than zooming. The HTB (Home Theater Brothers) is a basic prism lens with no coatings, no CA or Astigmatism correction. The Panamorph is a good lens but VC is really not the best choice for your application (occasional use), unless you plan to just leave it in place all the time.



Quote:

  • Lastly - which AR are most movies nowadays in 2.40 or 2.35 - i.e. how should I set up the screen?
It doesn't matter. The question is what AR are most of the movies you watch.
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post #38 of 89 Old 08-26-2014, 02:36 PM
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Originally Posted by stanger89 View Post
Honestly, I think you should just get a scope screen.

Both work fine, but they have different purposes. They work because the resulting shape is the same either way. The difference is a VC lens makes the image smaller vertically (ie Vertical Compression), where as an HE lens makes it larger horizontally (Horizontal Expansion).

Since you have a "fixed" height but want a wider image, you want an HE lens. Now a VC could work, but it means you either have to zoom the projector adjust/refocus/etc every time you move the lens, or you have to zoom and leave the lens in place all the time.

I'm not sure either option is better than zooming. The HTB (Home Theater Brothers) is a basic prism lens with no coatings, no CA or Astigmatism correction. The Panamorph is a good lens but VC is really not the best choice for your application (occasional use), unless you plan to just leave it in place all the time.

It doesn't matter. The question is what AR are most of the movies you watch.
I totally agree with all the above - EXCEPT -

The kicker here is that he says he can get an FVX200 for $500 (or thereabouts), so it may very well be worth it for the extra brightness and the lack of black bars when zooming. With that particular design, the brightness improvement will be considerable - PLUS there will be no black bars projected top and bottom. I would go for it, personally, especially if it can be returned if messing with it turns out to be a pain in the butt

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post #39 of 89 Old 08-26-2014, 02:43 PM - Thread Starter
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Originally Posted by stanger89 View Post
Honestly, I think you should just get a scope screen.
I only have room for 1 screen, and 90-95% of what I watch is 16x9

Quote:
Originally Posted by stanger89 View Post
I'm not sure either option is better than zooming. The HTB (Home Theater Brothers) is a basic prism lens with no coatings, no CA or Astigmatism correction. The Panamorph is a good lens but VC is really not the best choice for your application (occasional use), unless you plan to just leave it in place all the time.
Can you explain further-i.e. why is VC not as well suited for occasional use vs. HE? Am I better off leaving it (the VC lens) in place all the time (and then converting 16x9 to 1.33 - so the lens restores it to 16x9) or getting a slide - and only using the lens for 2.40. Basically I'm wondering how much of a difference the lens will make for my 2.40 viewing vs. zooming. Factoring in the cost ( $500) for the FVX200.

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post #40 of 89 Old 08-26-2014, 02:53 PM
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I totally agree with all the above - EXCEPT -

The kicker here is that he says he can get an FVX200 for $500 (or thereabouts), so it may very well be worth it for the extra brightness and the lack of black bars when zooming. With that particular design, the brightness improvement will be considerable - PLUS there will be no black bars projected top and bottom. I would go for it, personally, especially if it can be returned if messing with it turns out to be a pain in the butt
But cgott want's the scope image to be the same height but wider, meaning with the FVX he would have to zoom the projector, then put the lens in place. Resulting brightness would be the same as with an HE lens. Well it would be a bit brighter due to the larger aperture on the projector, but I'm not sure I'd call that considerable. And I'm not sure it would justify the expense given the added hastle required (zoom + lens + focus + lens shift probably) for only 5-10% of viewing.

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Originally Posted by cgott42 View Post
I only have room for 1 screen, and 90-95% of what I watch is 16x9
Not to be terse, but so what? What's the problem with having a scope screen and "not using" the sides?

Quote:
Can you explain further- Am I better off leaving it in place all the time (and then converting 16x9 to 1.33 - so the lens restores it to 16x9) or getting a slide - and only using the lens for 2.40. Basically I'm wondering how much of a difference the lens will make for my 2.40 viewing vs. zooming. Factoring in the cost ( $500) for the FVX200.
Well so with a VC lens you'll still be zooming, you have to make the picture wider with the projector's zoom since the lens doesn't affect the width. With an HE lens (at least a good one with focus correction) you just slide it in and you're done, 16:9 becomes scope, and then remove it when you're done. With a VC lens you have to zoom the projector, insert the lens, and likely adjust lens shift and focus. And then the reverse when you're done. So with a VC lens there's a lot more "setup" to do each time, it's not just slide it in, slide it out. At least not if your goal is Constant Height. VC lenses are really for constant width setups, and were really in their prime when we had low resolution, 4:3 projectors, so the added pixel density and brightness for 16:9 content was really beneficial. HE lenses are designed for constant height setups.

What the VC lens will do (vs just zooming) is get you 33% more brightness and pixel density. I guess given the fact that you'd be zooming either way (with a VC lens or with no lens) it comes down to if the extra brightness is really worth $500.

Personally, I'd rather have a seamless screen than a lens.

See what an anamorphoscopic lens can do, see movies the way they were meant to be seen

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post #41 of 89 Old 08-26-2014, 03:03 PM - Thread Starter
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Not to be terse, but so what? What's the problem with having a scope screen and "not using" the sides?...Personally, I'd rather have a seamless screen than a lens.
Good Q - the reason is that due to WAF - the screen needs to be motorized, and retract into the ceiling soffit. This soffit area is physically "only" ~100" wide - so going to a 2.40 screen would mean - the max image size for 16x9 would be 85" diag, instead of 104" via using a 16x9 screen.
The one avenue I have is that there is space on one side when the screen is down (hence the idea of the appendage).
If I could have the screen roll out from side wall to side wall (instead of ceiling to floor) - then I'd be set - and set up a 2.40. I couldn't think of a way to do that and keep the screen taut
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post #42 of 89 Old 08-26-2014, 03:24 PM
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Can you explain further-i.e. why is VC not as well suited for occasional use vs. HE?
As I stated above:

Since a compression lens makes the image shorter rather than wider, you will need to zoom the projector along with moving the lens into place in order to fill your larger screen (unless you want to leave the lens in place all the time, but as pointed out earlier, that means lower resolution 16:9 content).

And as Stanger has stated:

it means you either have to zoom the projector adjust/refocus/etc every time you move the lens, or you have to zoom and leave the lens in place all the time.


Of course, you need to adjust / refocus each time you zoom whether you have the lens or not.

Since you watch 16:9 most of the time, I wouldn't really be inclined to leave the lens in place all the time.

Question - can you try out the lens or return it if you don't like it?

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post #43 of 89 Old 08-26-2014, 03:33 PM - Thread Starter
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Originally Posted by John Schuermann View Post
Question - can you try out the lens or return it if you don't like it?
Unfortunately not. Sounds like I'm better off with the HE lens.
Of note - the HE lens (HTB) is AR coated.
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post #44 of 89 Old 08-26-2014, 04:05 PM
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Unfortunately not. Sounds like I'm better off with the HE lens.
Of note - the HE lens (HTB) is AR coated.
Personally, I would save the $200 and just zoom. AR just means "Anti-Refective." You will still have chromatic aberration and astigmatism issues with the HTB, which you won't have if you zoom. Why make the image worse?

I've attached a picture of what chromatic aberration looks like on a horizontal expansion lens, using a test pattern (labelled "before" and "1"). If your projector had electronic color correction, you could dial it out like you see in the image labelled "after." Your BenQ does not have this feature, so you will see the color fringing with the HTB lens. To be fair, this is harder to see with actual video content. However, this - combined with the lack of astigmatism correction - would make me lean toward dropping the idea of getting the HTB lens. The lack of astigmatism correction means that you can get sharp focus in the horizontal or vertical, but never both at the same time.
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post #45 of 89 Old 08-26-2014, 04:08 PM
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Originally Posted by stanger89 View Post
But cgott want's the scope image to be the same height but wider, meaning with the FVX he would have to zoom the projector, then put the lens in place. Resulting brightness would be the same as with an HE lens. Well it would be a bit brighter due to the larger aperture on the projector, but I'm not sure I'd call that considerable. And I'm not sure it would justify the expense given the added hastle required (zoom + lens + focus + lens shift probably) for only 5-10% of viewing.
Vertical compression designs result in brighter, crisper images than horizontal expansion by their nature. Shoot out an FVX200 with any horizontal compression lens sometime

Seriously - any HE lens.

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post #46 of 89 Old 08-26-2014, 05:30 PM
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Originally Posted by John Schuermann View Post
Vertical compression designs result in brighter, crisper images than horizontal expansion by their nature. Shoot out an FVX200 with any horizontal compression lens sometime
At the same image size?

I mean I sort of understand the logic that could lead to such a conclusion. By it's nature, a VC lens takes an image and makes it smaller. The smaller image with thus be brighter and as is usual of smaller images it will be "crisper" as you say. Likewise an HE lens, by it's nature, makes an image larger, and thus dimmer and less crisp. Both of these are in relation to the the lens not in place vs in place, not each other.

However that logic can't be extended to an "all else equal" comparison, by that I mean if you compare a VC lens throwing a 100" wide image to an HE lens throwing a 100" image with the same projector zoom, etc. They will be the same brightness because the same light out of the projector will be filling the same screen space.

I'd actually try it, I currently use a Prismasonic HD5000/AVS1 and have a Panamorph P752, but the the logistics of such a comparison make it, impractical. That and I already know that the Prismasonic is "better", the 752 produces CA and barrel distortion, while the Prismasonic is corrected for CA and I guess personally pincushion is less noticeable/objectionable than the barrel distortion.

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post #47 of 89 Old 08-26-2014, 07:13 PM
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Having played with both HE and VC, I would say that at the same image size, brightness is the same. The HE gives the option for true CIH in a movable lens system, where the VC does not.
The VC win is it allows longer thows, so by default reduces optical distortion like barrel.

I am about to buy my LED HD91 and in my 2.1:1 set up, the curve if the screen is perfectly offsetting the pincushion of the HE lens. If I was to use a VC lens, I would have to use the shorter throw HD90 and could use a flat screen because the amount of curvature from the barrel distortion is less that curvature of the HE at the same distance.

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post #48 of 89 Old 08-27-2014, 08:38 AM
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Originally Posted by cgott42 View Post
Unfortunately not. Sounds like I'm better off with the HE lens.
Of note - the HE lens (HTB) is AR coated.
What John is telling you about the image quality compromises on a HE 2 prism lens is correct. I can tell you from practical experience with a 2 prism CAVX lens on my Infocus X10 (a DLP like yours) that the visual anomalies aren't that bad. I saw some slight blue fringing on high contrast areas. Side focus was softer. But no one who had ever sat in the theater ever noticed. Most were very, very positive about the picture and impact the scope presentation made.

And for those suggesting to zoom. Not only would that be time consuming and a pain, but I think the original poster has stated he does not want to. I know 2 prism lenses are generally frowned upon by those with a $1000+ budget for a lens. But they work. And I found my experience with one to be pretty positive.

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post #49 of 89 Old 08-27-2014, 10:20 AM
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cgott42 does not need an anamorphic lens of any type. He is overthinking this project, and in a desire to be helpful and answer his questions, many in this thread are (inadvertently) overselling him on the benefits of a lens in his scenario.

Realistically, any gains he achieved in brightness with a vertical compression lens would be pretty minimal, and he won't gain real resolution in the content since there isn't any more in the source. If anything, he'll be doing unnecessary scaling for no reason.

He's going to have a 16:9 screen. The majority of content he watches will be 16:9. Scope movies will continue to be letterboxed in the center of that screen, with or without a VC lens. He does not need an add-on lens. If he does absolutely nothing and just leaves his projector set for 16:9, those letterboxed movies will be projected at the same uniform brightness as the 16:9 content he's already used to watching. There is no need to do anything different here.

It's time to inject some pragmatism into this thread and talk him down from wasting his money on something he doesn't need. A lens would gain him very little with what he plans to do.

If, in the future, cgott42 decides to install a 2.35:1 screen, he can debate whether or not to use an anamorphic lens at that time. There is no sense in fretting about that right now.

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post #50 of 89 Old 08-27-2014, 10:47 AM
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Originally Posted by Josh Z View Post
cgott42 does not need an anamorphic lens of any type. He is overthinking this project, and in a desire to be helpful and answer his questions, many in this thread are (inadvertently) overselling him on the benefits of a lens in his scenario.

Realistically, any gains he achieved in brightness with a vertical compression lens would be pretty minimal, and he won't gain real resolution in the content since there isn't any more in the source. If anything, he'll be doing unnecessary scaling for no reason.

He's going to have a 16:9 screen. The majority of content he watches will be 16:9. Scope movies will continue to be letterboxed in the center of that screen, with or without a VC lens. He does not need an add-on lens. If he does absolutely nothing and just leaves his projector set for 16:9, those letterboxed movies will be projected at the same uniform brightness as the 16:9 content he's already used to watching. There is no need to do anything different here.

It's time to inject some pragmatism into this thread and talk him down from wasting his money on something he doesn't need. A lens would gain him very little with what he plans to do.

If, in the future, cgott42 decides to install a 2.35:1 screen, he can debate whether or not to use an anamorphic lens at that time. There is no sense in fretting about that right now.
I misunderstood what he was doing as well. Unless he's changed again, he's actually going to construct "winglets" that attach to the 16:9 screen to convert it to a scope screen when needed. So an HE lens does make sense here. Unless I missed something.

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post #51 of 89 Old 08-27-2014, 10:47 AM - Thread Starter
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Originally Posted by Josh Z View Post
cgott42 does not need an anamorphic lens of any type. ..
If, in the future, cgott42 decides to install a 2.35:1 screen, he can debate whether or not to use an anamorphic lens at that time. There is no sense in fretting about that right now.
I appreciate the perspective. But I am going to be adding on to my screen to have a 2.40 screen (details in this post). I'm actually ordering the extra screen fabric now. I'm going to add addition fabric to one side (as no room on other side). Down side is very slight "bump" in screen due to addition fabric, and I have to lens shift, refocus (but being that 2.40 viewing is about once (maybe twice)/month - I can live with that.
I haven't seen a lens so I don't know the extent of the trade offs (not having seen them in person). The 2 mentioned above (DIY HE lens with coating for $200 or FVX200 VC lens for $500) seem to be what's available now (used). OR of course - just zooming for the 2.40

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post #52 of 89 Old 08-27-2014, 11:42 AM
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Originally Posted by cgott42 View Post
Down side is very slight "bump" in screen due to addition fabric, and I have to lens shift, refocus (but being that 2.40 viewing is about once (maybe twice)/month - I can live with that.
Only you can decide what you want to do and what compromises you've comfortable accepting, but I have a feeling you'll find that the join-lines between the original 16:9 screen and the extensions will start to be more noticeable and annoying after you actually live with them for a while. For the first couple of movies, you may be willing to ignore them. Over time, however, you may feel differently.

In any case, even if you do attempt 2.35:1 this way, I would strongly suggest starting by simply zooming the projector. Try that for a while before you make big decisions about adding an expensive lens.

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post #53 of 89 Old 08-27-2014, 11:44 AM
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Originally Posted by cgott42 View Post
I appreciate the perspective. But I am going to be adding on to my screen to have a 2.40 screen (details in this post). I'm actually ordering the extra screen fabric now. I'm going to add addition fabric to one side (as no room on other side). Down side is very slight "bump" in screen due to addition fabric, and I have to lens shift, refocus (but being that 2.40 viewing is about once (maybe twice)/month - I can live with that.
I haven't seen a lens so I don't know the extent of the trade offs (not having seen them in person). The 2 mentioned above (DIY HE lens with coating for $200 or FVX200 VC lens for $500) seem to be what's available now (used). OR of course - just zooming for the 2.40
The VC (vertical compression) lens would not be what you would want for your goal. As far as picture quality, I haven't thrown my old lens out on Craigslist yet. If I have time this weekend I will hold it up in front of my JVC and snap a pic for you. I found it to be pretty darn good for the cost.

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post #54 of 89 Old 08-27-2014, 11:59 AM - Thread Starter
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Originally Posted by Josh Z View Post
Only you can decide what you want to do and what compromises you've comfortable accepting, but I have a feeling you'll find that the join-lines between the original 16:9 screen and the extensions will start to be more noticeable and annoying after you actually live with them for a while. For the first couple of movies, you may be willing to ignore them. Over time, however, you may feel differently.

In any case, even if you do attempt 2.35:1 this way, I would strongly suggest starting by simply zooming the projector. Try that for a while before you make big decisions about adding an expensive lens.
Good advice. The cost of the additional screen material is not much (so worth trying), though the lens cost is reasonable ($200-$500), but you're probably correct - that it's worth holding off on the lens, until I'm sure that I'm OK with the extension. OR as John said - I'm gonna ask the DIY lens seller if I can try it out first.
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post #55 of 89 Old 08-27-2014, 12:20 PM
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Argh.

I find it difficult to be at odds with those I consider friends on this forum (Josh Z., Stanger89, and Jeahrens) because I usually agree with almost everything they say

First off, to be clear, I also advocate zoom as a way to test this particular setup, as I agree with Josh that the seams might become more and more distracting over time. Then again, they may not. In either case, testing out with zoom first will be a very inexpensive way to determine that.

What I think is getting continually misunderstood here is the value of a VC lens for this particular setup (in fact, I think there is major misunderstanding of VC lenses in general, which is part of what I am trying to correct). There ARE distinct advantages, especially considering the price being asked ($500) and in comparison to an HTB horizontal expansion lens. Here they are:

  1. The VC lens will give benefits even if relegated to a constant image width system only, in that the image will be considerably brighter than the standard letterbox image delivered from the same projector sans lens. In fact, this is where one can very realistically realize the "30% brighter" anamorphic lens benefit often debated on this forum. So, even if cgott42 ends up living with a constant width system and never does add on expansions, he can still derive a very tangible benefit from a VC lens - a much brighter picture and no projected letterbox bars.
  2. The VC lens will also eliminate the letterbox bars (for the vast majority of Scope films) if cgott42 does decide to add the extensions to his screen. When zooming we all know the bars will just end up being projected above and below the screen. As I pointed out previously, with a projector like the BenQ those letterbox bars will likely be quite visible, especially when projected on retractable screen black drop. It shares this advantage with an HE lens. The only caveat is that the image will need to be manually zoomed, which cgott42 will be doing anyway if he decides to go zoom method only.
  3. The FVX200 will unquestionably provide better picture quality than the HTB lens, as it has far, far less chromatic aberration plus has been corrected for astigmatism. I will go out on a limb here and say that the FVX200 delivers some of the best picture quality of any anamorphic lens, regardless of price.
  4. The only downside of the FVX200 is the need to zoom if cgott42 does add extensions or end up with a 2.40:1 screen, and the need to remove the lens from the light path when watching 16:9 (of course, he will need to do that with an HE lens as well). But read through his posts - he anticipates doing this only couple of times a month. Not exactly a major hardship.

All of the above said, I still recommend that cgott42 start out with zooming and see what he thinks before investing in either lens (this is why I kept asking if he could return the lens if not deriving a benefit). Once he gets a feel for how his system actually operates can he decide if the benefits of a lens are warranted. Just please keep in mind that the benefits of a VC lens apply to both constant height AND constant width systems.

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post #56 of 89 Old 08-27-2014, 12:30 PM - Thread Starter
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Originally Posted by John Schuermann View Post
The only downside of the FVX200 is the need to zoom if cgott42 does add extensions or end up with a 2.40:1 screen, and the need to remove the lens from the light path when watching 16:9 (of course, he will need to do that with an HE lens as well). But read through his posts - he anticipates doing this only couple of times a month. Not exactly a major hardship.
Don't mind the hassle of zooming, but is(n't) it true (what someone mentioned) - that the need to zoom the VC for 2.40 AR will negate the benefits in brightness/PQ gained by the lens?
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post #57 of 89 Old 08-27-2014, 12:49 PM
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Originally Posted by stanger89 View Post
At the same image size?

I mean I sort of understand the logic that could lead to such a conclusion. By it's nature, a VC lens takes an image and makes it smaller. The smaller image with thus be brighter and as is usual of smaller images it will be "crisper" as you say. Likewise an HE lens, by it's nature, makes an image larger, and thus dimmer and less crisp. Both of these are in relation to the the lens not in place vs in place, not each other.

However that logic can't be extended to an "all else equal" comparison, by that I mean if you compare a VC lens throwing a 100" wide image to an HE lens throwing a 100" image with the same projector zoom, etc. They will be the same brightness because the same light out of the projector will be filling the same screen space.

I'd actually try it, I currently use a Prismasonic HD5000/AVS1 and have a Panamorph P752, but the the logistics of such a comparison make it, impractical. That and I already know that the Prismasonic is "better", the 752 produces CA and barrel distortion, while the Prismasonic is corrected for CA and I guess personally pincushion is less noticeable/objectionable than the barrel distortion.
Yes, at the same image size. First of all, as you pointed out, opening the lens aperture to zoom also increases light output, and of course you need to zoom with a VC lens. Of course, the brightness increase when zooming varies with projector model, but you get my point. With a VC lens you get the light output advantage of zooming PLUS the light output advantage of using an anamorphic lens. Also, since there are fewer surfaces in a VC lens there is actually more throughput (although, admittedly, not a whole lot). So with the same projector throwing the same image size via HE or VC lens, the VC lens "created" image will be brighter. Depending on the projector model and the increase in brightness created by zooming, you could theoretically get up to twice the brightness increase over HE.

Other advantages of a good VC lens:

  • It's sharper than an HE lens, and over a wider range of throw distances. The sharpness at each color is superior to any other design.
  • The internal distortion can't be beat. There is a slight variation in height of each square of a grid pattern from top to bottom, but from left to right it is essentially invisible.

The downsides are the zoom issues already discussed (plus the associated long throw), and of course, there is no correct answer to "which is better, barrel or pincushion distortion." As pointed out by CAVX, though, the long throw distances required by VC lenses effectively minimize the barrel distortion regardless.

As I imagine you are aware, the 752 is a very old, oil-filled design. The current Panamorph FVX200 is considerably better due to tighter tolerances, better coatings, and - because it is not oil-filled - less "stuff" for light to pass through.

It's interesting, too, that in our ongoing efforts to bring anamorphic HD material to market through Folded Space (and we ARE making progress, btw), one of the things we are discussing with the powers that be is anamorphic content for Digital Cinema. The lens design being considered for DCI is vertical compression.

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post #58 of 89 Old 08-27-2014, 12:57 PM
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Originally Posted by cgott42 View Post
Don't mind the hassle of zooming, but is(n't) it true (what someone mentioned) - that the need to zoom the VC for 2.40 AR will negate the benefits in brightness/PQ gained by the lens?
No. See my just posted reply to Stanger89. When you zoom with the FVX200, you get the brightness benefits of zoom AND lens.

With either design - VC or HE - you get to use the whole 1920 x 1080 pixel grid. Does this result in "better" PQ? As others have pointed out, this does not add any real additional picture detail, as the Scope movie itself is limited to 1920 x 810 resolution (typically). But what most people report is that the image appears smoother and more "solid" with a lens system. There is also less "screen door" effect when using lens vs. zoom (plus of course the brightness benefit).

As someone who occasionally does consulting work for Panamorph, you are free to read any bias into my comments you like However, since we are talking about a used lens here anyway it's not as if Panamorph stands to benefit from your purchase in any way (or myself, for that matter).

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post #59 of 89 Old 08-27-2014, 01:54 PM
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Originally Posted by John Schuermann View Post
The VC lens will give benefits even if relegated to a constant image width system only, in that the image will be considerably brighter than the standard letterbox image delivered from the same projector sans lens.
If doing Constant Width on a 16:9 screen, would you really want the scope picture to be brighter than the 16:9 picture? In that scenario, uniform brightness at both ratios would be less distracting.

The brightness benefit of a lens is more important in Constant Height projection, where the 2.35:1 image is larger than 16:9, and consequently spread out over a greater area and dimmer. In that case, you want to preserve as much brightness in the scope image as possible.

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post #60 of 89 Old 08-27-2014, 01:57 PM
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If you are not opposed to zooming, that is the cheapest way to test this setup with $0 invested. And that is where you should start. I don't know the specifics of your BenQ, so I would be concerned about how your DLP projector will deal with zooming that much. I know some BenQ DLP's do have some lens shift to work with, but whether yours does or if it is enough I can't say. Certainly something I would want to research it. I know my DLP had no shift and zooming would not have been an option without some big placement changes.

I've never found John's comments to be a sales pitch or exhibit bias. He recommends what he is knowledgeable about and rightly so. I'm recommending the inexpensive 2 prism HE route because I know what it's like to be on a strict budget. If you need $$ for a lens and rear speakers then a $200-$300 savings is significant.
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