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2K views 17 replies 4 participants last post by  patela2oh 
#1 ·
Hello and thanks in a advance for the help... Got some questions to pick the forums brain on just to make sure I'm thinking correctly.


1) what is the difference between the Jvc dla-rs48u and the dla-rs4810u?


2) I'm thinking of using a 2.35 screen (1.3 gain, 130 inches wide) and using the lens memory for a CIH setup... Has anyone used this projector that way? Thoughts?


3) Jvc has assured me that the new memory system also memorized lens shift points and that I should be able to place the projector above the top edge of the screen... Anyone tried it yet?


4) Just checking my math. The projector has 80% vertical shift, this means that the projector can be placed z inches above the screen where (screen height) x (0.80) = z. So if you had a 100 inch high screen you could place the projector 80 inches above the top of the screen


5) any visible to the human eye difference in the contrast ratio of the 48u vs the 56u (50m vs 90m).


6) can this projector be used with moderate ambient light or does it need to be pitch black?


Thank you in advance
 
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#2 ·

Quote:
Originally Posted by patela2oh  /t/1459492/projector-help-jvc#post_22993514


Hello and thanks in a advance for the help... Got some questions to pick the forums brain on just to make sure I'm thinking correctly.


1) what is the difference between the Jvc dla-rs48u and the dla-rs4810u?


2) I'm thinking of using a 2.35 screen (1.3 gain, 130 inches wide) and using the lens memory for a CIH setup... Has anyone used this projector that way? Thoughts?


3) Jvc has assured me that the new memory system also memorized lens shift points and that I should be able to place the projector above the top edge of the screen... Anyone tried it yet?


4) Just checking my math. The projector has 80% vertical shift, this means that the projector can be placed z inches above the screen where (screen height) x (0.80) = z. So if you had a 100 inch high screen you could place the projector 80 inches above the top of the screen


5) any visible to the human eye difference in the contrast ratio of the 48u vs the 56u (50m vs 90m).


6) can this projector be used with moderate ambient light or does it need to be pitch black?


Thank you in advance

The 4810 has a 3 year warranty and an extra inspection by JVC. The 48 has a 2 year warranty.


A 130" wide 2.35 screeen has a screen height of 55.32". The projector lens center can be 16.6" above the image (55.32" x 0.30) above the image as long as no horizontal lens shift was used. The calculation of 0.8 is from the center of the screen. I just use .3 from the top of the image. In other words, .8-.5=.3.


In the right room with a screen size and gain optimized to allowing you to close the iris down, then yes the nearly double difference in contrast matters. If you are having to use the projector with the iris wide open, because you need the light output, then probably not.


You do not have to have a pitch black room. That sort of room improves the performance of any projector. Once again, you have to factor in size and gain of screen and if there is much ambient light, then you need to start to consider specialty screens made for just such rooms.
 
#3 ·
Like Mike said, cutting down on ambient light will help ANY projector look better. The whole point in purchasing a JVC projector is to have to the best black levels. If you know for a fact there will be ambient light, the JVC might not be the best option because that ambient light will kill it's one greatest feature; black levels. There are plenty of other projectors out there that do just about everything other than black levels a whole lot better and would be the logical choice if there is ambient light in the room. If not, go with the JVC and be happy.
 
#5 ·

Quote:
Originally Posted by patela2oh  /t/1459492/projector-help-jvc#post_22995049


I wanted to do a CIH setup with the bottom of the screen at 88 inches from the ceiling but avoid using a pole etc for the projector because the ceiling is 117.5... Any ideas or abandon ship, use a Epson 5020ub and a 130 wide 16x9 setup

Would having the bottom of the projector at 8' be a problem? If not you could use the JVC with a 12" drop tube and mount the 130" wide 2.35 screen so that the image started 30" above the floor. If you would like to discuss options, give us a call.
 
#6 ·
S
Quote:
Originally Posted by AV Science Sales 5  /t/1459492/projector-help-jvc#post_22993775


The 4810 has a 3 year warranty and an extra inspection by JVC. The 48 has a 2 year warranty.


A 130" wide 2.35 screeen has a screen height of 55.32". The projector lens center can be 16.6" above the image (55.32" x 0.30) above the image as long as no horizontal lens shift was used. The calculation of 0.8 is from the center of the screen. I just use .3 from the top of the image. In other words, .8-.5=.3.


In the right room with a screen size and gain optimized to allowing you to close the iris down, then yes the nearly double difference in contrast matters. If you are having to use the projector with the iris wide open, because you need the light output, then probably not.


You do not have to have a pitch black room. That sort of room improves the performance of any projector. Once again, you have to factor in size and gain of screen and if there is much ambient light, then you need to start to consider specialty screens made for just such rooms.

So I'm a little confused about the 30% shift vs 80% on the jvc. I was looking at the Epson 5020 and the pan 8000 and they have 90 and 100% shift vertically and using thier own calculators its actually 96% and 100 of the total screen height from the top. Is this a JvC only issue / calculation method?
 
#7 ·
Large amounts are shift are provided for to increase the marketability of excuse me lower end projectors. You will never see a top quality machine proving massive amounts of lens shift. If you have a machine like the Epson or Panny, maximize its performance by not using massive amounts of the lens shift provide. Generally, you do not want to mount the lens higher than the top of any projector screen.
 
#8 ·

Quote:
Originally Posted by patela2oh  /t/1459492/projector-help-jvc#post_22998856


S

So I'm a little confused about the 30% shift vs 80% on the jvc. I was looking at the Epson 5020 and the pan 8000 and they have 90 and 100% shift vertically and using thier own calculators its actually 96% and 100 of the total screen height from the top. Is this a JvC only issue / calculation method?

The lens shift numbers are usually calculated from the 0% lens shift position and that is center of screen. Do not look at the amount of lens shift and think a projector with more lens shift must be a better product. If that was the case then all of the really high end projectors would be the cheapest out there, because they have less lens shift than the cheaper projectors. Lens shift is a band-aid for imperfect set-up.


JVC's have 80% vertical lens shift from center or 30% from edge of screen.

Epson 5020 has 196% vertical lens shift from bottom/top or 96% from edge of screen.

Sony HW50ES has 71% vertical lens shift from center or 21% from edge of screen.


Use of horizontal lens shift (you should not use horizontal lens shift) detracts from the amount of vertical lens shift.
 
#15 ·
I moved the furniture around to make it easier to see... And I plan on moving it all back a foot. I have the access point for the projector 15 feet back along with all of the cables.


Thoughts on size , height etc? I could to a standard screen which ends above the LCR speaker or an acoustic perf that ends below the 6.5 inch tall LCR speaker


I wanted a 130 wide 2.35 but I wanted to avoid having the jvc 2 feet off the ceiling... Any ideas?
 
#16 ·

Quote:
Originally Posted by patela2oh  /t/1459492/projector-help-jvc#post_23008041


I moved the furniture around to make it easier to see... And I plan on moving it all back a foot. I have the access point for the projector 15 feet back along with all of the cables.


Thoughts on size , height etc? I could to a standard screen which ends above the LCR speaker or an acoustic perf that ends below the 6.5 inch tall LCR speaker


I wanted a 130 wide 2.35 but I wanted to avoid having the jvc 2 feet off the ceiling... Any ideas?

Sent you a PM.
 
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