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Cylindrical A-Lens Owner's Thread - Page 9

post #241 of 623
Quote:
Originally Posted by CAVX View Post

The main purpose of the window is to control noise from HVAC and projectors in the Cinema booth. Shutters can be used to control excess light.

From what limited info I have been able to find, iron free glass is supposed to prevent a tinting of the projected image.

I also found a supplier. It is not cheap as they wanted $400 for a 250mm (10") square at just 3mm thick.

So the use of this glass is extremely uncommon then.
post #242 of 623
Quote:
Originally Posted by GetGray View Post

Don't remember. What's your point? That the .04 difference is of consequence?

A big part of BD hype was about providing OAR. For DVD, the title would have just been panned and scanned back to 1.33:1 and as you have said, the 0.4 difference is not going to upset too many. Given BD is 16:9, it would be nice if all the classic films are presented as 1.37:1 because they have 33% extra width available on the format to do so.
post #243 of 623
Quote:
Originally Posted by oztheatre View Post

So the use of this glass is extremely uncommon then.

I think you'd find that the larger cinema chains like BCC do use it.
post #244 of 623
A loss of 25% horizontal resolution is a big loss. Trying to justify it by reference to a curved screen doesn't lessen the loss. It only makes the problem one of balancing rez loss against a barrel distorted picture.

I've long been an advocate for "personal preference". For example I like to watch quite a few 16:9 productions in 'scope. I balance the loss of cutting off someone at the knees v. cutting them off at the shins. Band Of Brothers is my favourite for this treatment. But not all films can take it: Elizabeth can be easily 'scoped out, while Elizabeth: The Golden Age suffers mightily from any cropping at all. This is all on a flat, pull-down screen that leaves me with a fully functional living room after the movie's finished. They say a plumber's plumbing is always dreadful. So is a lens designer's HT.

"Auteur" theorists agonize here over recovering the last pixel "that the director intended" and will obsess endlessly about their 'scope masking ("Is it 2.35, 2.37, 2.39 or 2.40... or is it 2.2, 2.21?" etc. etc.) when what the director intended was to make a living out of shooting the film and bedamned to how it's shown, or what the exact aspect ratio is after masking... within limits, of course. My predeliction for cropping 16:9 to 'scope AR in certain cases garners viable criticism from the purists. "Viable", but I don't care anyway.

Deliberately losing 25% of the image's detail seems like a sin to me - personally, I'd never do it just to accommodate a curved screen fetish - but if you don't like barrel distortion it's "praise the Lord and pass the ammunition". Cropping 16:9 to 'scope loses the same amount of information, so... go figure. I can't defend my own quirky film-watching habits and condemn others'. You paid for it, you have to live with it. But please let's not get into the pseudo-scientific mumbo jumbo about how our eye is better in the vertical direction than in the horizontal, to justify saving the cost of a sled.

In the end it's a matter of just sitting back and enjoying your personal choice. If the movie's any good then you won't give a toss anyway.

P.S. I have the HD-DVD version of Casablanca. It's really superb to watch, but let me say that for some reason the standard DVD version isn't far behind it in apparent resolution. I guess once I get into the movie (which I watch several times per year, preferably with an audience of people selected for never having heard of Humphrey Bogart, but who are familiar with some of the classic lines, like "Round up the usual suspects"), I don't really care. I have a DVD quality "roadshow" disk of Casablanca (the restored version) that I've added old trailers to, plus a couple of Warner Bros cartoons, and then comes the movie itself. It's always a hit if you can get your audience around to forgetting it's not in color (a hard ask with some of the young whippersnappers you get to meet nowadays).
post #245 of 623
On projector room glass...

You're going to get a largish light loss, even if the uncoated glass is at a normal to the beam axis. Ordinary BK7 loses 4% to 8% from 0 to 25 degrees angle of incidence respectively, at each air-glass interface. Then there is internal reflection within the pane of glass itself, which will deliver subtle but measurable ghost reflections on the screen.

I'm surprised to hear that professional cinemas don't coat their bio-box glass window surfaces. In fact I stand gob-smacked that they don't. It seems so obvious a thing to do to maintain quality. Perhaps whoever told the poster above that they don't coat their glass didn't know what he was talking about?
post #246 of 623
Quote:
Originally Posted by CAVX View Post

I think you'd find that the larger cinema chains like BCC do use it.

Ok but we're talking about home theatres not commercial theatres..

On commercial theatre complexes.... The quality of the image in commercial theatres is now being eclipsed by home theatres all over the place. The image clarity, colour temperature, sharpness and precision masking is better, hey even sound is better than what I've witnessed in both NSW and Qld over the years.

Still today I leave the cinema many times with a sour taste, either the sound was terrible and or nowhere near loud enough, the screen was dirty (teenagers having food fights) or people were arrogant and talked right thru the film (normally kids do this) not to mention that damn exit sign under the screen or to the left or right, or both!

Just the other month I saw a scope film, for the first 10 mins they had not opened up the curtains, so we had an awfully cropped scope image with about 4 damn feet of overscan on each side. I had to go downstairs and tell them to open the curtains... whatever.... Cinema complexes are being run by kids these days.

I'll take a Home Theatre any day of the week, booth or no booth!
post #247 of 623
Quote:
Originally Posted by Aussie Bob View Post

Perhaps whoever told the poster above that they don't coat their glass didn't know what he was talking about?

Just going by what the guy on the other end of the phone said and maybe he doesn't know everything about his products. Because I know that full windows can be anti-reflective coated, so I was very surprised to hear that too. The part he stressed that made this glass special was it was iron free and would not tint the colour.
post #248 of 623
Quote:
Originally Posted by Aussie Bob View Post

On projector room glass...

You're going to get a largish light loss, even if the uncoated glass is at a normal to the beam axis. Ordinary BK7 loses 4% to 8% from 0 to 25 degrees angle of incidence respectively, at each air-glass interface. Then there is internal reflection within the pane of glass itself, which will deliver subtle but measurable ghost reflections on the screen.

I'm surprised to hear that professional cinemas don't coat their bio-box glass window surfaces. In fact I stand gob-smacked that they don't. It seems so obvious a thing to do to maintain quality. Perhaps whoever told the poster above that they don't coat their glass didn't know what he was talking about?

I was a cinema projectionist for over 35+ years in Sydney and Auckland. I fought the likes of Village, Greater Union, Kerridge Odeon, Amalgamated Theatres for years to buy a better port glass, all they would install was plate glass. I said OK lets get something better for just the 35MM projection ports, the answer again was no! Some glass you could see all the distortion in the image as you removed it as the film way running it was truly shocking. All I could do was find the best glass out of all the "other" ports and at least use that one for the main projectors, Im sure its still the same today.

Its easy to see why Home Cinema easy beats the commercial cinemas!
post #249 of 623
Thread Starter 
Quote:
Originally Posted by Highjinx View Post

I see a mild conflict between the two statements above.

By down scaling one is loosing both detail and pixels (25%) and available brightness goes down too, not only by using less of the panel but losses from the lens. However since the image is smaller the brightness per unit area will be around the same as the wider 2.35:1 image.

I have heard the horizontal vs vertical detail dialogue, but I am yet to see any scientific published data. I put this in the same 'truism' catagory as one must drink 8 glasses of water a day myth!

I say move that A-Lens out of the way for 16:9...viva CineSlide!

Mildly conflicting? Thats what my psychiatrist used to say so I fired him but often wonder if I did the right thing. Anyway I meant to say Vertical resolution, not Horizontal.

Touche on the CineSlide.

Your right. The brightness will be exactly the same. between the 2.35 and 1.78 image. Maybe I just wanna use my lens al the time. And it probably has a lot to do with my small screen. I sit 3-4+ PH from the screen. When I change my viewing distance or move to a larger screen I will revisit using a sled. Maybe it will become an issue. Maybe not. At 10 screen widths, you probably can't tell the difference between 720P and 1080P.

I do consider myself a picky and demanding videophile, and have viewed every sort of projector (hundreds) over the last 24 years. I know want I like and base my purchases on this and not what's popular or base it on a review or on someone else's opinion. Sometimes I'm in the minority, sometimes the majority. Sometimes I'm ridiculed, sometimes others completely agree. Regardless of all that, it doesn't change what I purchase or how I use what I have. I really don't care how all the guys with mega home theaters do it. My situation is different and to me I'm doing it the right way. Who's to say you wouldn't agree with me if you came over. Having said that, I have an open mind and will revisit this method when I move to my new room and try it with extended viewing to determine what I like and what method I'll use.
post #250 of 623
Thread Starter 
Quote:
Originally Posted by Aussie Bob View Post

But please let's not get into the pseudo-scientific mumbo jumbo about how our eye is better in the vertical direction than in the horizontal, to justify saving the cost of a sled.

Suffice it to say, justifying saving the cost of the sled is not the issue to me. I don't see a difference otherwise I would have it. It's as simple as that. I bought my Isco 3L from Scott and will likewise purchase said CineSlide when I see fit. See post above.
post #251 of 623
Quote:
Originally Posted by RapalloAV View Post


I want to see pix of booths

And here is a couple with a cylindrical lens too

[back wall with projection port and back surrounds]


[close up of lens]

LL
LL
post #252 of 623
Lookin good Mark, you're not going to spray the rail black?

So this is a home cinema because of the booth? I see the benefit for mounting the rears on that panel, not sure there would be less noise though as the W5000 has intake and exhaust at the front.

The only issues I see with a booth is getting remotes to work from your seating positiion, (unless you use one of those IR sensors under your screen), space and cost. Otherwise it's a neat way of doing things.
post #253 of 623
Quote:
Originally Posted by oztheatre View Post

Lookin good Mark, you're not going to spray the rail black?

Thanks. I'd like to get that anodized to match the lens. The sled is a rough prototype to test the idea and it works well. I just chose not to use it for moving the lens out of the light path unless I want to focus the projector or need to demo Scaling for a client. It was installed so that if I moved the lens, I could get it back into the same position every time.

Quote:


So this is a home cinema because of the booth? I see the benefit for mounting the rears on that panel, not sure there would be less noise though as the W5000 has intake and exhaust at the front.

The top mount in the EQ rack does reduce some noise, not all. To make this into a "hush box" would require some lining of the inside (maybe foam) and the glass on the front.

The idea of the "false" back wall was to create an environment that more closely resembled a real cinema. Therefore the EQ rack should not be visible in the room. Things like eye lines to the screen were all worked out before any construction took place. I was lucky because I had the gear set up in another location, I could "experiment" there and not have to risk getting it wrong in the room. All 4 surrounds are just over seated ear height based on the rear row of seating. Their diffuse radiation pattern (combined with THX Cinema 2 processing) makes the sound field very enveloping.

When I designed the room, I worked the layout as the "actual room" (back wall to screen) plus extra depth for stage/screen (being AT) and the EQ Rack behind the back wall.

THX's 36 degree rule in a cinema is from screen edge to edge back to the centre seat of the back row. And they now have 45 degrees being their preferred seating distance. As it turns out, the BenQW5000's optics cause placement of the projector to be about 3.7x the image height, so when using the anamorphic lens, it works out about the same 36 degrees.

I elected to use two rows of seats where the front row is just past 2x the image height and the rear row is about 3.2x the image height. The room has reasonably good sound absorption (I think it needs some diffusion) and total light control. The room is also "decoupled" from the rest of the house and was constructed using rubberized adhesives - so it doesn't rattle - and doesn't leak sound as bad as it would if it were physically attached to the house.

Because I already had the screen, I designed the room around that so that it would deliver maximum impact and it sure does being wall to wall. If I was to build another room from scratch, I'd do the same, just on a larger scale.

Quote:


The only issues I see with a booth is getting remotes to work from your seating position, (unless you use one of those IR sensors under your screen), space and cost. Otherwise it's a neat way of doing things.

IR Repeaters can work well. The only thing is sometimes I'd like to be able to see the screen on the AVR as my Pioneer does not display on screen like some Onkyo units can, so maybe that's my next brand of AVR.
post #254 of 623
Thread Starter 
Quote:
Originally Posted by CAVX View Post

And here is a couple with a cylindrical lens too

[back wall with projection port and back surrounds]


[close up of lens]

Very clean and symmetrical. Excellent.
post #255 of 623
Thanks Cooldra Very dark too when the lights are out. I just love the fact that I can turn it up to 00dB (I usually watch about -15dB) with no rattles and know that I am not annoying the neighbors.
post #256 of 623
Quote:
Originally Posted by coolrda View Post

Mildly conflicting? Thats what my psychiatrist used to say so I fired him but often wonder if I did the right thing. Anyway I meant to say Vertical resolution, not Horizontal.

Touche on the CineSlide.

Your right. The brightness will be exactly the same. between the 2.35 and 1.78 image. Maybe I just wanna use my lens al the time. And it probably has a lot to do with my small screen. I sit 3-4+ PH from the screen. When I change my viewing distance or move to a larger screen I will revisit using a sled. Maybe it will become an issue. Maybe not. At 10 screen widths, you probably can't tell the difference between 720P and 1080P.

I do consider myself a picky and demanding videophile, and have viewed every sort of projector (hundreds) over the last 24 years. I know want I like and base my purchases on this and not what's popular or base it on a review or on someone else's opinion. Sometimes I'm in the minority, sometimes the majority. Sometimes I'm ridiculed, sometimes others completely agree. Regardless of all that, it doesn't change what I purchase or how I use what I have. I really don't care how all the guys with mega home theaters do it. My situation is different and to me I'm doing it the right way. Who's to say you wouldn't agree with me if you came over. Having said that, I have an open mind and will revisit this method when I move to my new room and try it with extended viewing to determine what I like and what method I'll use.

Agree wholeheartedly that how one wishes to view the image is a personal matter.

Objective PQ determination is another...........
post #257 of 623
Quote:
Originally Posted by Highjinx View Post

Agree wholeheartedly that how one wishes to view the image is a personal matter.

Objective PQ determination is another...........

Hey HJ, there is another GTG in Melbourne soon where I will be giving a talk on CIH and demoing the benefits of cylindrical lenses with adjustable astigmatism correction. Will I see you there?
post #258 of 623
Hi all Ive finally got the job finished. I would like to thank Phil from 1300 stereo and Mike from connect AV, both great guys and they done a job well done.

This is from the front looking back(but I guess you would no that) The paint is slight wet but I will put the proper photo on my Home theatre thread.




Photo without the lens



Photo with the lens
post #259 of 623
Very cool Franin Now it looks like a true CINEMA

EDIT: How serviceable is that? The reason my port is so big is so I can get the projector out through the hole for air filter and lamp changes.

I have thought about adding a cover plate with a much smaller hole that can be removed prior to removing the projector.
post #260 of 623
Quote:
Originally Posted by CAVX View Post

Very cool Franin Now it looks like a true CINEMA

EDIT: How serviceable is that? The reason my port is so big is so I can get the projector out through the hole for air filter and lamp changes.

I have thought about adding a cover plate with a much smaller hole that can be removed prior to removing the projector.

Thanks Mark! Well I can change the lamp in the other room and filter. Ill take a photo of that to give you an idea.
post #261 of 623
Quote:
Originally Posted by Franin View Post

Well I can change the lamp in the other room and filter. Ill take a photo of that to give you an idea.

Ok so you have access to the back. Cool I've basically got to remove the A-Lens, then take the whole projection mount out to service my unit. Lucky it is not something that has to be done that often
post #262 of 623


Yep its another room behind which I have moved all my gear into. the only thing that is left in my HT is speakers. We had to a remove some bricks for this project.
post #263 of 623
Quote:
Originally Posted by Franin View Post


Yep its another room behind which I have moved all my gear into. the only thing that is left in my HT is speakers. We had to a remove some bricks for this project.

WOW removing bricks! That sounds like serious renovation
post #264 of 623
Quote:
Originally Posted by CAVX View Post

WOW removing bricks! That sounds like serious renovation

yeah it was took a whole day to finish we don't have stud walls over here. Everything internal is Bricks!!
post #265 of 623
Quote:
Originally Posted by Franin View Post

yeah it was took a whole day to finish we don't have stud walls over here. Everything internal is Bricks!!

WOW! Is that a standard building code for WA or did you elect to have solid core walls? Might be a PITA to retro fit, however it must be good for sound isolation though
post #266 of 623
WoW Franko Awesome set up mate, A true theatre setup the way you have
your projector placed in another room, zero noise from your projector...

Is that Special clear glass in front of your Schneider lens?..
post #267 of 623
Quote:
Originally Posted by CAVX View Post

WOW! Is that a standard building code for WA or did you elect to have solid core walls? Might be a PITA to retro fit, however it must be good for sound isolation though

We built the house 10 years ago, before HT was the norm at homes and everything was bricks internal, actually it still is here.
post #268 of 623
Quote:
Originally Posted by cinema mad View Post

WoW Franko Awesome set up mate, A true theatre setup the way you have
your projector placed in another room, zero noise from your projector...

Is that Special clear glass in front of your Schneider lens?..

Thanks bud! There is no glass at all where the hole is. The room behind is quite big and lockable too.It stays mainly closed.
post #269 of 623
Quote:
Originally Posted by Franin View Post

Thanks bud! There is no glass at all where the hole is. The room behind is quite big and lockable too.It stays mainly closed.

It must be a join in the port material (MDF?) as I thought there was glass in there too.
post #270 of 623
Quote:
Originally Posted by CAVX View Post


It must be a join in the port material (MDF?) as I thought there was glass in there too.

No I wouldn't put glass.
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