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Discussion Starter · #1 ·
Hi, I have a Prismasonic FE1500m which works great with my current JVC HD100 (RS2). The HD100 is ceiling mounted and the distance between the centre of my 2.37:1 (246.5cm x 104cm) screen and the JVC lens is 359cm. The Prismasonic is slightly tilted so that the bottom of the projector lens sits just inside the FE1500's casing. However, I am contemplating moving to one of the new design JVCs and am very concerned that my Prismasonic won't work with their recessed lens and elongated body shape. The rear of my HD100 is 9cm from the back wall of my room and the new JVCs are 47.8cm long compared to the HD100's 41.9. So you see, I haven't got much space to play with at all (if only my room were a bit larger!).


Can someone help me do the number crunching to find out whether the new style JVCs will work with my lens? I'm really not sure when it comes to the FE1500m what effect the FE (which shrinks the image) has on calculating throw ratios. Can someone advise? If I can't do it with the FE1500m then I'm really stuck when it comes to upgrading. Thanks.
 

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Discussion Starter · #2 ·
I suppose if it's not possible then I may have to do the inconceivable and sell my Prismasonic, use some of the money to build myself a new huge 16:9 screen so that I can watch scope movies at their present size. If there's any cash spare from the lens sale I could put that toward a new projector.
 

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Discussion Starter · #3 ·
If my present scope image fills my 247cm x 103cm screen (thus technically leaving me with 16:9 images 190cm x 107) then what size will an unexpanded scope movie (not counting the black bars) be if I build a 16:9 screen that is 247cm x 139cm? My maths was never good so I'd appreciate it if some genius could help me work this out.
 

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I was able to make a HD5000 work with a BenQ W20000 and there are not too many projectors with a lens recessed as far as the W5000.20000 which is almost 2". The new JVCs do have a recessed lens, however it is not that much.
 

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Quote:
Originally Posted by CAVX /forum/post/18304059


I was able to make a HD5000 work with a BenQ W20000 and there are not too many projectors with a lens recessed as far as the W5000.20000 which is almost 2". The new JVCs do have a recessed lens, however it is not that much.

The problem is that the FE1500 (and all earlier models from Prismasonic) have a smaller rear opening than the HD5000 lens from Prismasonic. I have the same problem with my own FE1400 and a BenQ W5000, and I'm either selling the lens or changing the projector - just can't decide if I'm going to keep my CIH setup or changing to a regular 16:9 screen.


Gøran
 

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Discussion Starter · #7 ·

Quote:
Originally Posted by Goran /forum/post/18308593


The problem is that the FE1500 (and all earlier models from Prismasonic) have a smaller rear opening than the HD5000 lens from Prismasonic. I have the same problem with my own FE1400 and a BenQ W5000, and I'm either selling the lens or changing the projector - just can't decide if I'm going to keep my CIH setup or changing to a regular 16:9 screen.


Gøran

I've now decided to sell my Prismasonic and go back to 16:9. I can actually make my 16:9 screen as wide as my 2.37:1 now so I won't lose the size of projected scope material. The image will also gain some marginal sharpness, contrast and lumens as a result. It just makes sense.
 

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Quote:
Originally Posted by Goran /forum/post/18308593


The problem is that the FE1500 (and all earlier models from Prismasonic) have a smaller rear opening than the HD5000 lens from Prismasonic. I have the same problem with my own FE1400 and a BenQ W5000, and I'm either selling the lens or changing the projector - just can't decide if I'm going to keep my CIH setup or changing to a regular 16:9 screen.


Gøran

The only differences I could see comparing the FE1500 to the HD5000 was that the side plates on the rear prism have been removed allowing the full width of the glass to be used and the new sexier stand.
 

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Quote:
Originally Posted by Canary_Jules /forum/post/18308598


I've now decided to sell my Prismasonic and go back to 16:9. I can actually make my 16:9 screen as wide as my 2.37:1 now so I won't lose the size of projected scope material. The image will also gain some marginal sharpness, contrast and lumens as a result. It just makes sense.

And you gain black bars on most movies too.
 

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Discussion Starter · #10 ·
I plan to use the motorised vertical alignment function to realign the image so that the bottom black bar falls below the screen and then drop down some masking from my ceiling to mask the top bars. So not too much difference for me in reality.
 

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Quote:
Originally Posted by Canary_Jules /forum/post/18309449


So not too much difference for me in reality.

In reality the difference is about 270 vertical pixels. With your lens, you get 1080 for all ARs. Going back to zooming means that you get 810 for Scope and 1080 for 16:9/4 x 3. No doubt, you know that already, you probably have not seen it with your own eyes yet. The only positive is 1:1 pixel mapping.
 

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One of the things I found when I got my lens was that contrast seemed improved: I'm now at minimum zoom in the projector which maximises the contrast due to the way the projector's lens is made, but when zooming I was using around 1.33 zoom which reduces the ON/OFF contrast according to Cine4home's review of the HD350. While putting glass in front of the projector should reduce the ANSI to some degree, the improvement in ON/OFF for the same size screen seemed more noticable for me.


I'm not so sure about the lumens gain as I thought that was the point of getting a lens (though the projector's brightness will increase inversly to the contrast for the same reasons above, so this may well compensate).


However, all you have to do now is remove your lens and try it to see how you get on. I did this a short while after I got my lens and found I prefered the image with the lens, YMMV as they say, but don't sell it until you've tried it without.
 

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Quote:
Originally Posted by ilsiu /forum/post/18312029


I don't think he's planning to zoom. I think he's planning to go CIW.

Except true CIW requires a 4 x 3 display, not a 16:9 display. 16:9 is both CIH and CIW.
 

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Quote:
Originally Posted by CAVX /forum/post/18312050


Except true CIW requires a 4 x 3 display, not a 16:9 display. 16:9 is both CIH and CIW.

When someone mentions CIW, you honestly think of a 4x3 display? In this day and age with 16x9 displays (and sources) so ubiquitous?


Anyway, fine: he's considering 16:9 and 2.35 CIW.
 

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GO BACK TO 16/9 you can do that????
 

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Discussion Starter · #17 ·
Alas, given the limits of my room dimensions, I don't think I have a choice if I want to upgrade from my RS2. The new JVCs have the recessed lens and Prismasonic have now confirmed to me that my FE1500m won't work with it at my max throw range. So it would be a case of selling the FE1500m and buying the 5000 but that will cost me about £1000 and that's before I've bought a new projector. Far cheaper to sell the lens and go back to 16:9.
 

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Quote:
Originally Posted by CAVX /forum/post/18308631


The only differences I could see comparing the FE1500 to the HD5000 was that the side plates on the rear prism have been removed allowing the full width of the glass to be used and the new sexier stand.

I stand corrected. The construction of, and the mounting for the rear prism has been changed to allow for a larger light beam to enter the rear prism without changing the the rear opening of the housing. I guess I should have been more accurate in my reply, but the problem remains the same - doesn´t fit!


Gøran


by the way, the new mount does look a lot better than the old one!
 

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Quote:
Originally Posted by Goran /forum/post/18316266


the problem remains the same - doesn´t fit!

I think the original prisms width was just 65mm which by removing the sisde covers increased it to about 68mm. If they had increased the size of the prisms, it is possible that the rotation would not work to allow bi-pass without changing the entire alloy case design. I fully understand why they did what they did.
 

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Quote:
Originally Posted by ilsiu /forum/post/18312339


When someone mentions CIW, you honestly think of a 4x3 display?

Yes as that is the basic standard for all TV systems.
 
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