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# Cylindrical A-Lens Owner's Thread - Page 12

Quote:
Originally Posted by Gary Lightfoot

It's the throw before expansion

Thanks. So in my case (see data a few posts back) the A-Lens throw ratio is considered to be 1.76x, and not 1.40x, is that correct?

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Quote:
Originally Posted by Gary Lightfoot

Smaller throw ratios are not recommended because the size of the image coming out of the projector could be too large for the A lens, so the sides of the image can be obstructed by the A lens casing. In photography they call it vignetting.

With larger lenses, a smaller throw can be accommodated, but because you're using more of the A lens' glass area, you can get more pincushion. With a smaller beam, you use less curve on the A lens glass, so get less pincushion.

Gary

Hi Gary, perhaps add to this. If one is using a shorter throw and getting a larger amount of pincushion, a curved screen would be a good option in order to counter that distortion. Otherwise stick to longer throws of around 1.8 ish or greater where possible.
madshi: Here is a foolproof formula to calculate the TR. It's what I recommend everyone use. It takes the 1.78 or 2.35 question out of the equation, literally.

TR= (d * 0.5625) / h
where d is the distane to your screen from the Projectors owm (prime) lens
h is the height of your screen.
Use the same units for d and h

Example: 54" tall screen, 12' from PJ

TR = 144" *0.5625/54" = 1.5
Somewhat OT... Just read a review in HT mag of the Dreamvision projector. An \$8K option adds a Schneider a-lens. In the pix of the lens in the mag, the lens mount looks incredibly cheesy for an \$8K lens. Pretty sad for that much coin...
Quote:
Originally Posted by SteveHorn

Somewhat OT... Just read a review in HT mag of the Dreamvision projector. An \$8K option adds a Schneider a-lens. In the pix of the lens in the mag, the lens mount looks incredibly cheesy for an \$8K lens. Pretty sad for that much coin...

It doesn't look that bad. Interesting that they have moved to cylindrical lenses over the precious prisms based lenses. LINK
Quote:
Originally Posted by CAVX

It doesn't look that bad. Interesting that they have moved to cylindrical lenses over the precious prisms based lenses. LINK

I expected to see beefy posts, like those shown in the Schneider ad in the same issue. Even the pj reviewer, Tom Norton, commented on the difficulty of affixing the lens to the mount etc. - stripped out screw and such.
I agree. That mount is PITIFUL.

If you know where to ask, you can do better in every way (Mount and lens).
Quote:
Originally Posted by CAVX

Apparently its been delayed - again.

plastic - good for 720, not so good for 1080 or so i was told

But, why 1080p alone and how does this new model being compared with Panamorph, Aussiemorphic, Prismasonic in terms of performance?
It is impossible to know how it will compare to anything, yet. It's not available, they are having trouble producing it I believe. They do not elaborate as to the reasons. My opinion is that this lens will not be anywhere near the performace of their glass lenses. If it were, why would anyone buy their glass anymore? At the price that it might be sold for (again time will tell), they would never sell another glass lens if it performed as well. It would be glass suicide. I don't see then doing that. Ther original intent years ago was to produce something that would be competitive with the lower end market, specifically Panamorph, and it's clones. So I think it will be (if they get it out) competitive with them, how well, dunno. But, typically speakng, the plastic lens projectors haven't fared well in the market IIRC. Certaintly not on the high end or even medium end side of things. But time will tell, if they get it out. And then there's the question of how uniform of a product will it be? Again, time will tell if they can produce them consistently. It's been a year since I saw the first one. Still don't have one.
Quote:
Originally Posted by madshi

Guys, I've a question about throw ratio. I've seen mentioned that A-Lenses shouldn't be used for throw ratios smaller than 1.5x. But what throw ratio are you refering to here? Is it the throw ratio with or without using the A-Lens to fill the Cinemascope screen?

CIH screen width: 280cm
distance to projector: 392cm
throw ratio for 2.35:1 movies: 1.40x
throw ratio for 1.87:1 movies: 1.76x

Is my throw ratio ok for an A-Lens or is it too small? Would any A-Lens do, or would it have to be an Isco IIIL?

To be honest, one major reason for my considering of using an A-Lens is that it might allow me to use projectors which I couldn't use otherwise. E.g. the TruVue Vango only goes down to 1.5x. Using zoom only the Vango isn't able to fill my screen. But with an (HE) A-Lens it would fit. But again that makes me wonder if my throw ratio is too small for an A-Lens or not, respectively if I could do with one of the upcoming bang-for-the-buck A-Lenses or if I needed the very expensive Isco IIIL.

The old saying "you get what you pay for" never rings more true than when an A-Lens purchase is considered. I bought my first lens before the Isco IIIL was around. Knowing what I know now wouldn't consider anything but a true Cylindrical lens. I'm so glad I paid the difference to step up to my Isco. Many times I've tried to save a buck only to repurchase the better product at twice the price later. From now on I can concentrate on Projector upgrade and not second guess my A-Lens purchase.
Quote:
Originally Posted by coolrda

The old saying "you get what you pay for" never rings more true than when an A-Lens purchase is considered. I bought my first lens before the Isco IIIL was around. Knowing what I know now wouldn't consider anything but a true Cylindrical lens. I'm so glad I paid the difference to step up to my Isco. Many times I've tried to save a buck only to repurchase the better product at twice the price later. From now on I can concentrate on Projector upgrade and not second guess my A-Lens purchase.

Exactly and projectors are getting better and better at a good price too!!
Quote:
Originally Posted by GetGray

I agree. That mount is PITIFUL.

If you know where to ask, you can do better in every way (Mount and lens).

That mount is bad!!
Quote:
Originally Posted by eummagic

But, why 1080p alone and how does this new model being compared with Panamorph, Aussiemorphic, Prismasonic in terms of performance?

Panamorph = glass
Aussiemorphic = glass
Prismasonic = glass

At a given screen size, the pixels on a 1080 are way smaller than they are for 720. It is said simply that glass passes the finer detail better.
Quote:
Originally Posted by GetGray

madshi: Here is a foolproof formula to calculate the TR. It's what I recommend everyone use. It takes the 1.78 or 2.35 question out of the equation, literally.

TR= (d * 0.5625) / h
where d is the distane to your screen from the Projectors owm (prime) lens
h is the height of your screen.
Use the same units for d and h

Example: 54" tall screen, 12' from PJ

TR = 144" *0.5625/54" = 1.5

Just what I needed, that clears up any confusion - thanks!

So my personal throw ratio is 1.85:1. Phew, that's good news!

Quote:
Originally Posted by coolrda

The old saying "you get what you pay for" never rings more true than when an A-Lens purchase is considered. I bought my first lens before the Isco IIIL was around. Knowing what I know now wouldn't consider anything but a true Cylindrical lens. I'm so glad I paid the difference to step up to my Isco. Many times I've tried to save a buck only to repurchase the better product at twice the price later. From now on I can concentrate on Projector upgrade and not second guess my A-Lens purchase.

Yeah, I understand. However, if you look at some of the comments in this thread, it might make sense to wait a little:

Alan Gouger: "Another cylinder lens is about to enter the market. [...] Top performance. Should put a dent in the market."

Aussie Bob: "I understand that at least one these two new lenses will be a lightweight, low-distortion, 5-element design, arranged in 3 groups, which is a much-needed improvement on the traditional Schenider/Isco (and other) 4-element, 2-group designs"

To those in the know: Will those upcoming lenses be able to compete with an ISCO IIIL with a 1.85 throw ratio with a 0.95" chip DLP projector? Or are those new lenses too small for such a setup?
Quote:
Originally Posted by GetGray

madshi: Here is a foolproof formula to calculate the TR. It's what I recommend everyone use. It takes the 1.78 or 2.35 question out of the equation, literally.

TR= (d * 0.5625) / h
where d is the distane to your screen from the Projectors owm (prime) lens
h is the height of your screen.
Use the same units for d and h

Example: 54" tall screen, 12' from PJ

TR = 144" *0.5625/54" = 1.5

Thanks for that, definitely good to know
Quote:
Originally Posted by madshi

To those in the know: Will those upcoming lenses be able to compete with an ISCO IIIL with a 1.85 throw ratio with a 0.95" chip DLP projector? Or are those new lenses too small for such a setup?

Well at least one of those new lenses does have the same size (5" wide) front lens allowing TR's as short (projector pending of course) as 1.4 (actual install) to be used.
Quote:
Originally Posted by CAVX

Well at least one of those new lenses does have the same size (5" wide) front lens allowing TR's as short (projector pending of course) as 1.4 (actual install) to be used.

Thanks. Looking forward to those new lenses to be released then...
Quote:
Originally Posted by madshi

Thanks. Looking forward to those new lenses to be released then...

Just an FYI, the one I'm talking about is already out
Quote:
Originally Posted by CAVX

Just an FYI, the one I'm talking about is already out

It is? Where can I find detailed information (specs, price etc) about it?

Edit: You mean your MK4?
Quote:
Originally Posted by madshi

It is? Where can I find detailed information (specs, price etc) about it?

Edit: You mean your MK4?

Yes the one and only "Australian First" and it is almost 12 months old now. I guess being "square" and at it current price point, it technically could be a considered a "world first".
Quote:
Originally Posted by CAVX

Yes the one and only "Australian First" and it is almost 12 months old now. I guess being "square" and at it current price point, it technically could be a considered a "world first".

Well, I think Minolta had the first square A lens I ever saw. Made for Marantz. Little bitty thing as shown by my business card. Neevr made it to production. The little buggers are harder to make right than enterprising folks think:
Back to the "XL", here are some photos I have from a production Schneider XL and the Isco IIIL (identical sized glass):

(sorry about the copyright watermarks).

Quote:
Originally Posted by GetGray

Back to the "XL", here are some photos I have from a production Schneider XL and the Isco IIIL (identical sized glass):

(sorry about the copyright watermarks).

Damn there nice lenses!!
Quote:
Originally Posted by CAVX

Panamorph = glass
Aussiemorphic = glass
Prismasonic = glass

At a given screen size, the pixels on a 1080 are way smaller than they are for 720. It is said simply that glass passes the finer detail better.

Thanks CAVX, I understand glass performs better than plastic. My doubt earlier was glass prisms vs cylindrical plastics - now cleared
Go Glass
Be nice to see the day when a material is developed for lens use when one has to touch it to 'see' if it is actually there.....cause' it's so transparent!....
Quote:
Originally Posted by GetGray

Well, I think Minolta had the first square A lens I ever saw. Made for Marantz. Little bitty thing as shown by my business card. Neevr made it to production. The little buggers are harder to make right than enterprising folks think:

Wasn't that little lens actually prisms based? I saw one of these at CEDIA 2009. I can not honestly say if it was a prototype or an actual production model as it did have a serial number. And I'm sure a DTV Forum member had one (cost him \$7K just for the anamorphic adaptor) which he bought with the Marantz projector (and the lens/sled combo). I'm sure he said it was prisms based in his review. The thing was small, so would work only with the longest throws.

Here is another link with a slightly different angle.

Mine is certainly the first "square cylindrical lens with adjustable astigmatism correction"
Quote:
Originally Posted by CAVX

Yes the one and only "Australian First" and it is almost 12 months old now. I guess being "square" and at it current price point, it technically could be a considered a "world first".

Gotta admit that when I saw it was square I thought it couldn't be cylindrical. Obviously I was wrong...
Quote:
Originally Posted by madshi

Gotta admit that when I saw it was square I thought it couldn't be cylindrical. Obviously I was wrong...

Your not the first to think that either, but I was wrong also.
So did anybody do an ISCO IIIL vs. CAVX MK4 shootout yet?
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