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Discussion Starter #21
My throw is too short then at about 13ft. I would probably have the same issues that exist with my current lense. I need a new house I guess!
 

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Scott Horton, techht.com
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To be clear, it's the throw ratio that is the limit, not the throw distance per se.


TR = (distance to screen/screen height)*0.5625


The small Cinedigitar requies a minimum 2.3 TR with a JVC RS35. And that's pushing it.


example: In order to use a 54" tall screen with that lens and a JVC RS35 without vignetting, the prime lens (PJ) would need to be 216" (18') from the screen.


example2: for a 13' throw distance, the largest screen you could use without vignetting would be 39" tall.
 

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Discussion Starter #23

Quote:
To be clear, it's the throw ratio that is the limit, not the throw distance per se.

Yes, that's correct. Thanks for clarifying. My 113" diagonal 2.40:1 screen, with a 13' throw is not optimal for the smaller anamorphic lenses.
 

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i nevermore sit around and bid on auctions. determine the max you are willing to spend and then use a snipe program to do your bidding. don't get in bidding wars. don't let emotions control your bidding decisions. put in one bid at the closing and either you win the item or you lose the item but you don't lose your $$$.


if you're willing to spend $1k then set the snipe bid at $1k. your bid goes in at the last second (i believe 3 seconds is the minimum) and if someone hasn't bid it higher you'll win at a buck over the last bid. you haven't let yourself get into an emotional bidding war.



auctionstealer.com
 

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Quote:
Originally Posted by bh285 /forum/post/20938798


Are you just making me feel better, or are you saying the Isco II alone is not worth 2k? Still a good lens though right?

I sold mine for $500 a few years back. I bought it when it was the best a-lens available and used it for 4:3 to 16:9 expansion. When I got a 1080p 16:9 projector the cons outweighed the pros, so I got rid of it. Now they have isco III, sleds, and curved screens that eliminate more cons, so I'll re-evaluate when I get a 4k projector, but I think isco II is well past it's prime.
 

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Quote:
Originally Posted by rabident /forum/post/21083410


I sold mine for $500 a few years back. I bought it when it was the best a-lens available and used it for 4:3 to 16:9 expansion. When I got a 1080p 16:9 projector the cons outweighed the pros, so I got rid of it. Now they have isco III, sleds, and curved screens that eliminate more cons, so I'll re-evaluate when I get a 4k projector, but I think isco II is well past it's prime.

Funny that I use an Isco II with a 1080p JVC and don't have an issue with it (other than non true CIH when it's moved out of the way). It's mostly due to my very long throw setup at 2.7 or thereabouts, but I don't suffer issues such as excessive pincushion (about 1" over 9.5' width) or uneven focus. I'm not sure what other cons you might be refering to, but I bought it used as a test and decided it was an improvement in my setup over zooming.


I can see that the prices you guys pay are lower than in the UK, but if you can find one for $500 then IMHO that's a bargain for those that can accomodate a long throw setup like mine, so I don't consider it's past it's prime. FWIW I paid £800 for mine used about 2 years ago and in the UK I'd be surprised if I couldn't get most of that back again, which is much better than the £2,000 depreciation on my JVC projector in the same period.
 

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Quote:
Originally Posted by Kelvin1965S /forum/post/20947552


Yes, but it could be read as if it wouldn't work for 16:9 to 2.35:1 so I just wanted to make it clear to the OP and others that this isn't the case as that's exactly what I use mine for. I don't leave mine in place if it's a 16:9 movie, so I have to slightly adjust the zoom on my projector to fill screen height.

It is still based on 1.33x and where 1.33 x 1.33 = 1.78 and 1.78 x 1.33 = 2.37. The difference between this lens and others is the fact that it also has vertical magnification where a true cylindrical lens like the ISCO III does not.
 

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Discussion Starter #29
I think the slight vertical magnification of the ISCO II would be annoying to me. I really prefer the "set it and forget it" method. Readjusting for different aspect ratios would be a non-starter for the wife as well. That means the II series lenses are not for me. I'd still like to give the ISCO IIIL a try, but I have my doubts that the 13' throw I have is enough.
 

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Quote:
Originally Posted by bh285 /forum/post/21086025


I think the slight vertical magnification of the ISCO II would be annoying to me. I really prefer the "set it and forget it" method. Readjusting for different aspect ratios would be a non-starter for the wife as well. That means the II series lenses are not for me. I'd still like to give the ISCO IIIL a try, but I have my doubts that the 13' throw I have is enough.

The ISCO II was meant to be left in the light path all the time and when you do this, the system is set and forget.


An ISCO IIIL will work with TRs down to 1.3:1.
 

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Quote:
Originally Posted by CAVX /forum/post/21086127


The ISCO II was meant to be left in the light path all the time and when you do this, the system is set and forget.

True, this is what I do if I know my main feature is 2.35:1 so any 16:9 trailers or TV that I watch after the film can be watched at CIH at the press of a single button. It wouldn't be an issue for my OH either. However as I don't leave my lens in place the rest of the time when I'm not using the projector I make the conscious decision as to whether I set up for 16:9 non lens or 2.35:1 with lens.


If I'm watching a whole film I prefer to use all the pixels so my 16:9 non Isco II is as good as any 16:9 non Isco III viewing would be.
Also due to my very long throw my 2.35:1 viewing has to be slightly electronically cropped. My 16:9 setting in my Lumagen just has the cropping turned off which neatly compensates for 99% of the Isco II magnification.


This hobby is all about compromises of some sort, but for me those relating to my Isco II are one of the minor ones: Not being able to have a dedicated room with completely black walls is my biggest one for example.
 

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Hey some are right into tweaking and that fine. Myself, I just wanna watch and know that everything works from the push of a button.
 

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Discussion Starter #33

Quote:
The ISCO II was meant to be left in the light path all the time and when you do this, the system is set and forget.


An ISCO IIIL will work with TRs down to 1.3:1.

I see, so an external scaled is required with an ISCO II for folks like me. Too bad the IIIL is so costly. There's no way I'd get that through the budget committee :-S
 

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Yes, with an Isco II left in place you need V-Stretch for regular scope viewing, but also 4:3 mode (Horizontal squeeze) for 16:9 content (at reduced resolution of course). Those options are built into all recent (and current?) JVCs for example so not necessary to have an external VP, though due to menu structure not as convienient to access as on a 'proper' VP.
 

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Does anyone know the percentage of vertical magnification that occurs when using an Isco 2? I'm still using my CRT with 9 foot wide 2.35 screen. I'm on the fence w so many digital options, throw ratios, etc. knowing this would greatly help. Would it be inches when projecting from 13' away?
 

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I'm not 100%, but I seem to remember reading somewhere that the vertical magnification is somewhere in the order of 1.05x or 5%. It is small, but would be the difference between running a true CIH system and not. Maybe it was done this way to offset the small differences seen in 2.40:1 films Vs 16:9 full frame.
 
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