Schneider or Isco iii ?

Its been said that the schneider will be better for longer throws while the Isco 3 offers greater flexibility which is obvious due to the lens size which can accept larger beam sizes, im using mine for shorter throw

IMO no second guessing with the Isco 3 it covers more bases

cant go wrong with either one of these lenses

Sorry guys, no time to make a spiffy shot today. But here's a teaser I had on the camera anyway. It is a 2 post mount as can be seen, unlike the stock single post mount. Adusts in height, pitch, roll, yaw:

It's against the rules to discuss pricing or marketing here. I only posted it here becasue so many have asked. But to answer somewhat, I'd wait... but of course I would

Scott, that's the thing of beauty. Why can't the same be done for the ISCO II/III?

Functionally they are the same. They have the same adjustment capabilities that is. One of my prime design goals was to keep costs down on the slide and make it as affordable as possible. The Isco and Schneider ar already pricey enough.

In the case of the Isco, I simply took advantage of their existing mount. Since most if not all users already have the stock table mount, all they have to do is slide their lens off the table stand's posts, and slide it onto my posts.

The Schnieder mount will cost more since it's obviously more involved that 2 posts (but from what I understand, my mount is still significantly more affordable than theirs). The Schneider mount had to be redesigned because I am confident their mount is not suitable for a motorized slide. The stock mount had minimal clamping power and even when tight can be pushed/moved by just a little extra hand force. That's fine for a stationary table mount, but when on a slide, and hanging upside down from a ceiling, I could give a list of what could go wrong. No engineer would allow a design with the stock mount upside down, and moving. There was no choice but a redesign in this case. A perk is that the redesign is better than the stock mount even for a table mount (Humble, but honest opinion). And it will likely be available as a standalone tablemount for that reason.

The main reason I don't run out and make a similar mount for the Isco's is they have a huge threaded interface. That is, it threads onto it's mount plate with about a 4" diameter super fine thread. The Schneider uses a bolt-on clamp ring that sandwiches the mount plate, a much easier design to interface. Machining the threaded Isco part would be expensive, thus working against one of my prime goals. If there were enough demand, I could use their mount plate and change the side clamps to those like the Schneider's CineSlide mount. However, note that the final Cineslide is all black, and includes black anodized posts for the Isco's. So it will transform a Isco to a 100% black unit, posts and all. That said, I don't know many would want to spend an extra few hundred for spiffy side clamps. Once it's adjusted and set, it should be over, never moved again.

Cheers,
Scott

I would love to have an ISCO III or Schneider but I'm not even sure if either is the best choice for my projector (IN76). Any comments here?

And then there is the little problem of big $$. I want a lens that looks good with the IN76 and would most likely work with any future 1080p projector. Any comments here?

I have my IN76 on a glass top table with its lens about 18' from the wall. Not sure what my "throw" is other than the 17-18' distance from lens to wall. Is that considered a long or short throw and are the two lens mentioned above appropriate for the IN76's "throw"? Comments please!

I do plan on a DIY curved screen eventually. Is this a factor in lens selection? Comments please!

Right now though, I need to decide on a lens before proceeding any further, then a remote controlled lens sled that is aesthetically pleasing would be great.

As there is no way to mount the lens and or sled to a glass top table and the lens can't be screwed onto the IN76 (no threads) how is this combination made stable so that you are not constantly repositioning the lens/sled? Comments/ideas please?

With everything out in the open and exposed I really like the look of the ISCO III and CineSlide2 mount. It looks better with the IN76 than anything else I've seen. As the IN76 is very visible, if possible I want to avoid the overly add on boxy look of other lens that I've seen. Comments!

Any and all suggestions would be greatly appreciated. I'm really unsure here.
Thanks guys!!

if youre willing to spend the $$$ the flexibility of the Isco 3 lens is invaluable both now and in the future

Any further info on this lens? I checked their website and found little to nothing.

You mean the Isco III?, search here for lots of information (search +"Isco III". Among most experts, it is the end-all 2.35 lens. It is large and can handle any projector and short throws, too. As Funlvr mentions, it is somewhat future-proof since it will continue to fit any PJ upgrade you use.

The Schneider is a similar very high quality ground glass lens. Schneider and Isco have history and share similar lens technologies. The Schneider is a very nice lens, but it is limited to projectors with longer throws and those that don't have a huge beam size coming out of the stock lens. See this review:

http://www.projectorcentral.com/schn...anamorphic.htm

Schneider is working on a projector matrix as we speak, but they haven't got it ready yet. Once they do, I'll post it on my site with other lens info (www.techht.com). They are also coming out with a larger lens. It will not be as large as the IscoIII though. It will be about halfway between a IscoIII and the current Cine-Digitar. I believe that size will address the majority of projectors. My 777 with a 1.8 throw just barely does not fit through a current Schneider (without minor vignetting) . But it fits through the Isco III with inches to spare.

HTH,
Scott

Do 30 % difference in pricing between ISCOIII and Schneider worth it?

They actually have an 8" (200mm) model out now. I honestly don't see a need for lens that large when the 6" ISCO III can do a TR as short as 1.3:1. It also costs way more than the ISCO III as well - like 2x as much

I have photos of it on my site HERE...just scroll down to the CIH stuff...

Mark

There is so much misinformation written about the legendary TR capacity of various lenses I thought I'd present a few basic points to consider.

The Isco can only do its theoretical TR of 1.3 when its back element, which is approximately 98mm in diameter, and its front element (about 134mm in diameter) does not vignette the beam from the projector. A 98mm diameter circular back element equates to an approximately 42mm x 28mm wide area of usable glass. The rest of the glass, above and to the sides of the light path, is wasted.

There are several factors in determining the size of the image when it reaches the back element of an anamorphic lens.

1. Mechanical clearance
A projector with a protruding lens that allows the anamorphic lens to be mounted closer to it, clear of any mechanical obstructions, will deliver a smaller beam to the back element of the anamorphic lens than an optically identical projector with a recessed projection lens or an elaborate case the protrudes in front of the lens.

In some cases, like some Sim2 Domino models, the first point of mechanical clearance is about 60mm (2.4") out from the projection lens. The beam will be pretty big at this point, the closest you can mount your anamorphic lens.

On the other hand, all the Panasonics and the JVC RS series have lenses that are jut out well in front of the case. You can mount your anamorphic lens as close as 15mm (0.6") from these projectors.

2. Focal length and f-number value of the lens
Larger imaging chips (like 0.95" DLP) require longer focal length lenses than smaller imaging chips (like 0.6" LCD chips).

The gauge of brightness of a lens is its f-number. f-number equals focal length divided by the lens's effective physical diameter at its smallest point.

An f2/100mm focal length lens has an effective aperture twice the size of an f-2/50mm lens. Hence the beams of light repesenting all the rays from individual points on the imaging chip, close to the projector (where the anamorphic lens is mounted), will be approximately twice as wide with the 100mm focal length lens as with the equivalent 50mm focal length lens. This is so even if the throw, screen size and TR set-ups are identical between the two projectors you're comparing.

As these beams of light (or "ray pencils") eminate from every point on the imaging chip, the size of the image close to the projector will always be bigger for DLP projectors than it is for LCD projectors for any given mounting offset, as the ray pencils at this short distance will add to the size of the image at that same point. They all end up as focused points on the screen, yes, but close to the projector there are significant differences in image size between projector types. These differences directly affect the ability of the anamorphic lens to accomodate beam width.

So far, it boils down to this: an anamorphic lens that easily accommodates a TR of 1.3 when it is mounted 15mm from an LCD projector, may only be able to accommodate a TR of 2.0 when it is mounted 60mm from a DLP projector. So, to say that the Isco will accommodate a TR of 1.3 is not anywhere near the full story. The mounting offset and the projector type have to be taken into consideration. They are absolutely crucial considerations.

An anamorphic lens that works with a given TR with one projector may not work with the same TR using a different projector.

Hence, Throw Ratio itself is not the sole determinant of whether an anamorphic lens will work in any given situation. At best it is a rough indication.

Which brings us to...

3. Beam angle
Beam angle is related to TR as well.

Even though the beam may fit the back element of the anamorphic lens, its angle (between opposite sides of the beam at its widest) may be too wide to make it through all the elements inside the lens.

It's quite possible for the end element (the one closest to the screen) to be too narrow, even though the back element (the one closest to the projector) is wide enough to accommodate the beam, if the TR is very small. This is especially true with projectors that force the user to mount his or her anamorphic lens way out in front of the projection lens, due to mechanical obstruction, or elaborate "designer" cases.

Conclusion
In determining whether an anamorphic lens will accommodate a particular beam you have to consider, at least, back element size, internal element sizes, mounting offset of a particular projector, type of projector (DLP v. LCD) and lastly Throw Ratio.

In addition, the anamorphic lens may not work as well when mounted, say, 3" from the projector, as opposed to, say, 3/4" from the projector. It may have, probably would have, a sweet spot closer to the projection lens where its optics work best.

The Isco and Schneiders are hardly likely to be exceptions to this basic rule of optics. You can only design-in so much flexibility to a lens. Originally, anamorphic optics were mounted almost flush with the film projector, literally screwed onto the end of the projector's prime lens, in very close proximity to its optics.

With digital projectors, and users' set-ups having an almost infinite range of mechanical constraints, zoom ratios, varying f-numbers through those zoom ratios, Throw Ratios, throw distances, beam angles and so on, it's impossible to design an anamorphic lens which will accommodate all of the many possibilities with equal performance quality.

And anyway, if you can afford an Isco, you should be able to afford a bigger HT than TR=1.3

Does anyone have anything to say about the new baby Isco 3-S vs. the Schneider digitar ?

How Schneider and Isco III compare with high end prism based lenses such as Panamorph UH480. Is it possible to summarise the additional benefits.

Focusable. Nothing else is verifiable because no-one releases any specifications.

According to Shawn Kelly himself, the UH380/480 have about 25% more distortion (I assume he is talking pincushion) than the ISCOIII. He posted about it here:

http://www.avsforum.com/avs-vb/showt...7#post11931427

I also recall reading where the UH380 passed 92% of incoming light, but I can't find the source of that info at the moment. The UH480 is supposed to be higher due to better coatings. Not sure how this compares with the ISCO III, but I suspect the ISCO III would be higher, more like 97%.

I measured about 3% loss from my UH480.

The problem with discussing prismatic lens distortion versus cylindrical lens distortion is that no-one gives distortion figures, so it's pretty hard to point to any hard data that support the case either way.

In general, prisms are likely to distort more than cylindrical systems, as the prism system designer has less degrees of freedom, in that there are basically four plano (flat) surfaces to use and not much more. The corrector lenses that Panamorph and Prismasonic use only correct for astigmatism, not distortion. They make focus even, not geometry.

On the other hand the cylindrical manufacturers can bend any surface, change any lens shape to alter distortion performance (at the expense of other performance if it's not done right). Cylindrical manufacturers - Schneider and Isco - make no claims about distortion specifications for their products. In fact they make no claims at all, much, except that there's no magnification in the vertical plane... in other words screen height doesn't change. That's about it.

To go further, neither Schneider nor Isco seem to provide any guidance on how to set up their lenses for best performance. Many reports on this Forum claim there was nothing inside the box when they received their Isco or Schneider but the lens itself. Panamorph and Prismasonic do provide detailed instructions on how to set up their lenses. This may be because lining up prisms is more critical for good performance than lining up cylindricals. Whatever the reason the instruction PDFs that come with these two prism systems are welcome.

To a certain extent the dearth of specifications from the cylindrical manufacturers may be due to worry on their part that they might burst the bubble surrounding their supposed superb quality. Not to say that their lenses aren't sharp, but any mention of pincushion, or distortion, or softness at certain throw ratios, or mechanical mounting offsets changing quality is likely to be misread (either deliberately or out of ignorance) by potential users as a "flaw". Better to say nothing and let the users' imagination go to work for them and their products.

I'd be pretty sure the cylindrical manufacturers have somewhat tackled the distortion problem, compared to the prismatic manufacturers (who have, as pointed out above, fewer degrees of freedom to work with). But I say this in the certain knowledge from my own design exercises and knowledge that it's impossible to get rid of all distortion for all (or even a respectable sampling) of the possible scenarios their lenses are claimed (either by the manufacturers, or on their behalf by enthusiastic users) to work within.

The other reason specifications might be in short supply is: how do you define your test parameters? Tell me how you use your lens, and I'll tell you how I use mine. The only way to find out is to eyeball lens performance in a definitive test, taking measurements off the screen while projecting a formal grid test pattern. Repeat this process for wide throw ratios, narrow ones, long throws and short, with the lens close to the projector and mounted several inches out from it. Then repeat the test with a dozen different projectors encompassing several different optical systems: telecentric DLP designs, LCOS, LCD and so on... in other words tens, if not hundreds of scenarios where the result will all be different. So why bother, especially if a misreading of the test results might result in losing sales?

You only need one or two users who are pushing the performance envelope of a lens to report a poor quality picture, too much pincushion or large grid distortion and it can poison sales, even if the test parameters the user employed are meaningful (this is not at all guaranteed).

Better to keep quiet and let the buzz work for them.

I was informed indirectly by SIm2 UK, that the Isco 2 lens has 5% magnification. I am not sure whether they were refering to the old isco2 or Isco3S.

I am perplexed to learn that this magnification may apply to only the vertical plane, so objects are distorted in looking vertically longer.

That was the old Isco II and I'm not sure whether it was a 5% magnification or a 5% reduction. But the figure I saw admitted to by an Isco engineer was 5%. The Isco II would have had some cross-rotated cylindricals or outright spherical surfaces in it, changing the vertical magnification. These extra surfaces help in astigmatism and pincushion reduction, but you lose CIH as a result. Incidentally, the expansion in the horizontal direction was slightly more (or less) than 1.33x, compensating for the 5% (plus or minus) change in the height. It's quite a lot, though, 5%. That's 2.5 inches in a 50 inch high screen.

The Isco III specifications (such as they are) clearly state a magnification of "1" in the vertical plane, i.e. unity magnification, no change in height.

A member who owns the isco2 on the UK Avforums has stated that there is 5% magnification. Presumably in the vertical plane and also 5% more than 1.33x in the horizontal plane as you suggest, thus countering any distorsion ie. so People's faces would not look long ? So it is a 5% magnification of everything.

I would intend to leave the lens in permanently so CIH wouldn't be necessary. I am on the lookout for an isco2.

It is an old obsolete lens. I believe its target when first made was to expand a 480i 4:3 pj to 16:9 with permanent fixed installation.

It was discontinued many years ago because it was not of the quality deemed appropriate for HD home cinema.

The IIIs was recently introduced and is designed for todays projection technologies.

You'll probably find there's still a very slight non-unity magnification in the Isco, and indeed any anamorphic lens. Even though there is no curvature in the vertical direction, there is still glass for the light to pass through and that glass will refract light ever so slightly away from the original path that it had straight out of the projector.

Even passing light through a pane of flat glass will change the screen height by a smidgin. The thicker the glass the more the displacement. The more panes of glass, the greater the displacement. If a lens is 150mm long, with multiple surfaces of differing kinds of glass, then the displacement will be more.

Not to worry too much, though. My modelling shows the change in height is usually less than 0.25%: that's 1/8" in a 50" screen height, or 1/16th" at both top and bottom. Not worth fretting about, but still there.

I get the feeling that if the lens makers admitted this very slight non-unity magnification it would cause them more trouble from the "screen height" and "director's intention" tragics among us than it was worth. Better to just say "Magnification = 1" and leave it at that.