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Discussion Starter · #1 ·
considering upgrading to the sharp 12k in conjunction with a constant height setup. I would like a 105"X45" 2.35:1 screen and then vertically mask to 80"x45" for 16:9 ratio mat'l. I don't care to view any 4:3 mat'l. Can I just put this projector in a fixed ceiling mount and use the zoom till fill the wider screen without having to move the projector back? Then just use the lens shift to bring the image down a bit to fit the sreen?

After reading the rather good comments about this pj's great image in the low lamp/high contrast mode. I would like to use this mode exclusively. Will it be bright enough with a 1.3 gain white screen; or do I need to use a high power or silverstar?(again the max screen size I will be using is 105"x45") This will be located in a basement with a low ceiling ( just under 7') top of the screen will be 1.5" from ceiling. The bottom of screen a little over 2ft from floor. I read the high power doesn't give as much gain with ceiling mounted pj's because of retro-reflective surface. Being that this is not a tall room, will I still benefit from this screen? I am pushing the limit of my budget if I choose this pj and want to avoid the high cost of using the silverstar (unless I have to go this route) btw.. fairly good light control in this room.
 

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First let me state that I am not a 12K owner. I do have a constant height set-up with a High Power screen, ceiling mounted PJ, and I am seriously considering the 12k.


From the specs, the 12K has ample zoom range to achieve constant height from one position. Please correct me if my math is wrong.


If I'm reading your post correctly, you may need to consider a couple of things. If your projector is ceiling mounted, when you zoom to make the image wider, you might need to bring the image up or down with the lens shift. It depends where the projector is mounted within the screen height. If it's mounted inverted at it's highest possible postion (aligned with the top of the screen), then when you widen the image, the increase in image height will all be at the bottom (The top of the image will remain in place. The bottom will be lower.) So accounting for the top letterbox bar, your picture (2.35 image) will be below the screen top, and you will need to shift the image up, sending the letterbox bar onto the drop above the screen's viewable area.


If your projector is mounted somewhere in the middle of the screen height, then when you zoom in, I assume both the top and bottom and bottom of the image move. Sharp owners please confirm or correct.


You can also shift the 2.35 image vertically within the 16:9 frame with the Sharp's vertical position adjustment. I know this functions on the component inputs, and I think it does on DVI as well. Sharp owners please confirm.


Using lens shift, or vertical position, remeber that you will have letterbox bars below, above, or both (depending on how high you mount the PJ) your screen's veiwable area. You will need to have the extra drop, or some type of masking or black cloth behind the screen to absorb this light. If the viewable are of your screen starts 1.5" below your ceiling, you will need to vertically shift all your letterboxing to the bottom of the image.


Also remember that if your PJ has any overscan, this will make a 2.35 image slightly taller than 2.35:1. If you want the image to fit your new screen perfectly, get the projector first, and measure the image height of some 2.35 films.


I hope this all makes sense. I assure you it's very easy to use. You just need to be aware of a few things so you order your screen properly.


Regarding the High Power with a ceiling mount: The closer in height the projector is mounted to your head the more gain you will get, so the lower you can mount your projector the better (for gain). Even with none of the gain, you still get the benefits of excellent off-axis light rejection with no hot spotting. I have not seen the Silverstar.


My set-up is just like the one you are contemplating. In use it only involves turning the zoom ring and the vertical adjustment. I think you will find it very much worth the slight effort.


Pip
 

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Discussion Starter · #3 ·
Thanks Pip, it is starting to make more sense.. My pj will probably be about 2-2.5 ft above my head. a bit more when reclined. Will I get any gain from a high power? would a carada bright white(1.4 gain) be enough for the 2.35 size screen in high contrast mode? I am confident that a silverstar would be plenty bright but would it be too bright when i mask down to 16:9?
 

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Echo,


With your head 2.5ft below the projector, you will certainly get some gain from the High Power. How much, I really don't know yet. I will do an experiment and give you a guestimation, although I might not be able to do it until Monday. I believe there is a post where someone did all the calculations on the gain of the High Power over various angles. (Perhaps someone with a better memory can provide a link, or at least a search hint.)


I've never seen the Silverstar or the Carada screens, so I can't comment on them. Do some searches here and on the Screens forum for High Power, Silverstar, and Carada. You will find some great info. There is a huge screen comparison done by Tryg.


Based only upon what I've read here, I doubt any screen will be too bright for the 12k.


If you're planning on ordering your screen through AVS (and you ought to! - especially as you're in western New York) call Jason and discuss it with him. He's seen the screens and the projector. You'll get nothing but great info from these guys.


I'll post back when I do my 2.5ft test.


Pip
 

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Echo,


I did my unscientific experiment tonight. I taped some sheets of printer paper on the screen. These should be very close to a gain of 1.0. Moved my head from just below the projector all the way down until the gain on the screen matched the gain of the paper. I used 0, 70, and 100 IRE fields just to be sure.


I estimate that if there is a gain of 2.8 right at the projector, at 2.5ft below the projector you probably have a gain of at least 2.0. I had to take my head down a good five feet lower than the projector to get the paper to match the screen in brightness.


Not very technical, but it might be of some guidance.


Pip
 

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echo,

First, I have the Z12K... If you zoom the image to get the right vertical height on the 2.35:1 material, there will still be the black bars on the top and bottom, albeit they will be off of your screen. Do you have some kind of masking above/below the screen so that you will not see that?
 

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Discussion Starter · #7 ·
misterfan.. yes I will have masking around the screen ; I plan on using a fixed wall mounted screen with the whole rest of the wall painted a satin black.

How long have you been using your 12k? do you like it?,and what is your screen size and mat'l? if I may ask


Pip.. thanks for taking the time to do your study.. I am also thinking of mounting the pj as far back as i can to have a smaller angle therefore squeezing out every bit of gain I can.


i am thinking that a high power may be bright enough for my theater. I do know that a silverstar will be just going to get pricing on both and take it from there.
 

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echo,

I have had my Z12K for about 3 weeks now. I really like it so far. My screen is 78" diagonal fixed 16:9 with black masking all around. It is actually just a painted rectangle on my wall (flat pure white, of course) with flat black painted moulding around it (like a picture frame). It looks great, and I didn't have to spend a grand on a screen. I painted the rest of the wall dark red, so the screen really leaps out, and everyone assumes it is some kind of professional fixed screen when they see it!


Just so you know... the zoom, focus, and lens shift functions on this bad boy are all MANUAL. It cannot be done with the remote. So, if you ceiling mount, I hope you can easily reach the controls (all around the lens) without having to climb up on something. Otherwise, you may want to reconsider your strategy.
 

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Discussion Starter · #9 ·
I assumed the focus,and zoom were manually operated, however; I didn't know the lenshift was also manual... Since i am setting this theater up in a basement with a low ceiling it will be within easy reach(although power zoom and shift would have been nice)... I haven't made my final choice as to pj quite yet (leaning toward 12k at this point)I should have the balance of my furniture delivered in the next three weeks.
 
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