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Pulling the trigger on an Infocus 4805 (1 Viewer)

Kyle-K

Stunt Coordinator
Joined
Jan 15, 2001
Messages
62


I think a lot of people are choosing the 92" because of the large offset of the projector... I was looking at those two sizes and chose the 92" because the 106" would have been lower than my center speaker...

Be sure to look into the offset when considering your screen size... especially if you don't have a high [9'+] ceiling.

--kyle
 

Patrick Nevin

Stunt Coordinator
Joined
Apr 21, 2004
Messages
99
I am actually going with what Craig W's answer because I will be sitting 7' from the screen and the 92" screen will be way too big.

Quick Edit: Do u think it would be ok to go to a 50" screen?
 

Craig W

Second Unit
Joined
Jul 28, 1999
Messages
445


Patrick,

I am by no means an expert, but I think you are going to find that none of screen manufacturers make a screen that small. 92" is one of the smaller sizes in the 16x9 format, there may be some 80" options but that would still be too large unless you moved your seating position back to the end of the room. I have a feeling if you end up with a 50" FP system you are going to be disappointed because it is not any larger than a typical plasma/LCD-RP/DLP-RP set. Either move your seating position back farther to get a larger screen or consider other options like a 1280x720 LCD projector. Minimum recommend distance with that resolution is 1.5-1.6x screen width. You could pull off a 5' wide image with the following screen dimensions:
60"w x 33.75"h
Diagonal size approx 68"

Not trying to scare you Patrick, but I would be very leary of your dealer. It would be one thing if you are close to the 2x distance, but you are way too close with that PJ. A big image is not impressive if you can see screen door and individual pixels.

Let me know what you decide. The SP4805 is a good PJ but it still is low resolution.

Good luck
 

micah bjj

Stunt Coordinator
Joined
Jul 13, 2004
Messages
60
Kyle- I actually meant to ask if the 4805 would be a good choice to use with a 96". Sorry about the misinformation.

Has anyone experienced a 4805 with a 96" screen?
 

Patrick Nevin

Stunt Coordinator
Joined
Apr 21, 2004
Messages
99
I talked to my dealer this evening and he also thought that the screen was to big also. He dose have a 70" screen available so he is gonna talk to his tech to see if that will be a good screen size from how far back i will be to the 4805's resolution. If not then maybe i can get a different pj like an LCD pj that Craig W mentioned. I will keep you guys updated. Man I am REALLY glad I became a member of this forum because it is people and information like this that really helps someone like me out.
 

Craig W

Second Unit
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Jul 28, 1999
Messages
445
Patrick,

If you end up going the LCD route the two most popular models at that resolution are the Sanyo PLV-Z2 and the Panasonic PT-L500. The Sanyo has some features like lens shift that make set up easier but either machine would be a good choice overall if you end going the LCD route.

Just remember that each display technology (DLP, LCD, CRT, etc) has its own strengths and weaknesses.

Let us know what's up with your final setup.

Craig
 

Scott Dautel

Second Unit
Joined
Oct 6, 1998
Messages
471
Regarding screen size & viewing distance ...
This never ceases to confuse people. There are too many variables invloved. After lots of study of DLP FP's & RPTV's, I have come up with a simple working formula. It goes like this:

To avoid screen-door effect, your screen needs to be sized so you sit at least 1200 pixel-widths away (assuming DLP with 20/20 corrected vision ... for LCD, typically farther depending on pixel fill factor )

So here's the math for Patrick with the InFocus 4805 (480 x 854 pixel array) ...

1200/854 = 1.405
for 7 feet viewing distance (eyes to screen center) = 84"
84" / 1200 pixels = 0.07 in/pixel
0.07 x 854 = 59.78" (maximum screen width)
59.78 x (18.36/16) = 68.6" max. 16:9 screen diagonal.

or you can go at it, beginning with screen size:

start with 92" diagonal 16:9 screen
92 x (16/18.36) = 80" screen width
80/854 = 0.0937 in/pixel
0.0937 x 1200 = 112.41" = 9.37 feet minimim viewing distance.

I wont bore you with the math a 3rd time, but the real answer for a 7 ft viewing distance and a screen approaching 100" diagonal is that you need a front projector with at least a 720 x 1280 pixel array. This is the TI Mustang HD2+ DLP chip, wich is the engine used in the InFocus ScreenPlay 7205 projector (street price > $5000.-)

An excel spreadsheet makes this really simple. I have simple graphs if anyone wants 'em

regards,
Scott
 

Jim Mcc

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Jim
What is the offset of the 4805? How do you figure it out? I plan to use a 52X92 screen. Due to a low ceiling, 6'8" tall, I'll have to use a table mount if I get the 4805. Thanks.
 

Citizen87645

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From the manual:

The image offset is 127.3% when the projector is in 16:9 mode. This means that if you have an image 10’ high, the bottom of the image will be 2.73’ above the center of the lens.

If I'm calculating correctly then the center of the projector's lens would be around 14" off the floor. The center of the lens is around 3" from the bottom of the projector, so your stand (or more like stool) would have to be around 11".
 

Patrick Nevin

Stunt Coordinator
Joined
Apr 21, 2004
Messages
99
I haven't heard back from my dealer yet. So I have been looking up some LCD projectors and later i am gonna read the article that Scott Dautel referred me to. I am also gonna look up a little more expensive DLP projectors if that is the way I have to go. but not worth $5,000. I will let you know how it goes.
 

Christpher_S

Stunt Coordinator
Joined
Apr 25, 2004
Messages
54


It seems close to me. I'm assuming Scott has seen the 4805 at the distance he says will be OK and that's why he would go against what the other people recommend after they watch one. I haven't seen this projector on any screen, so I can't do anything other than pass on recommendations from others that have seen it.

-Chris
 

Brian Corr

Supporting Actor
Joined
May 10, 1999
Messages
535
Everyone's eyes are different but I wouldn't go closer than 12' on a 92" screen with the 4805. And yes, I've got a 4805 and a 92" screen.
 

Scott Dautel

Second Unit
Joined
Oct 6, 1998
Messages
471
Regarding the 9' viewing distance ...

I actually said 9.37 ft. for a PROJECTED IMAGE that is 80" wide (at 10.675 pixels/inch). I'm saying this is the CLOSEST you really want to be, and I certainly stand by it. Any closer and your going to start to see individual pixels on a typical DLP (like my X1).

The SP4805 is actually a little better than my X1 since there have been several subtle but significant improvements made to the DMD itself. I won't bore you with all the details, but pixels on the HD2+ chip blend together better than they did on the earlier TI DMD used in the X1.

If yo want to make a comparative assesment to my 9.37' viewing distance, go to a store that is showing the new Samsung HLP-series DLP RPTV's. find a 56" (diagonal) unit and position yourself 46" away (about 4 feet). This is 1200 pixel-widths on an HD2+ DLP chip. Can you see pixels? for typical human visual acuity, that's about the lower limit.

Patrick:
I dont understand what you are fretting over. The 4805 is perfect for you ... just make the screen a little smaller & mount the the PJ a little closer if necessary. If you are planning on a fixed screen, you can make it yourself, any size you want for < $25 (a little more if you want to pay for premium screen material from Dalite or Carada).

Jim:
This discussion about offset is totally unnecessary. Remember projectors in grade school ... when they didn't hit the screen, we put a book under the front feet. The offset was not perfect on my [ceiling-mounted] X1 either. I used a calculator to figure how thick of a "book" I needed, cut a strip of wood; mounted the PJ and wood strip (under back feet, to raise the image closer to the ceiling in my case) to a beautiful, edge-routered, painted oak, mounting board and attached everything to the ceiling. A tweak to the X1 keystone setting and the image hits my screen to within 1/8" of where I wanted it from the beginning. voila!

Scott
 

Stephen Bort

Agent
Joined
Feb 17, 2004
Messages
40
A question about noise for you 4805 users...

Here's what I'd do if I bought it today...if I mount it 11.1 feet back in the room (the farthest it can go back because of a drop AC conduct) from a 7.5" ceiling, then I get a 72" inch screen (great for me since I've only currently got a 30" screen). My seating is 10 foot away from the screen. That means that the projector will be about 3 feet nearly directly above my head. What's the noise going to be like for me? I'm pretty sensetive to ambient noise, so I'm starting to wonder if I'll ever be able to get used to the sound of a projector.

Thoughts?
 

Citizen87645

Reviewer
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Cameron Yee
The majority of the noise issues from the front of the projector, so if you're three feet directly below it I think it will be less noticeable than having it about a foot behind you and just above your head (my situation). That's not to say it still won't be a distraction if you are sensitive to the white noise. I found I couldn't get used to it so I built a hushbox. I had to redesign it a couple times and almost gave up, but once I got a quality set of fans and closed the thing up I'm glad I did it. I still have a couple of detail items to do to make it look decent and an official temperature test to do to have the reassurance of adequate airflow, but it makes a huge difference.
 

Patrick Nevin

Stunt Coordinator
Joined
Apr 21, 2004
Messages
99
Hey Scott I will ask my dealer if they can install the 4805 closer to the fixed screen. They were looking at a 70" screen to see if that would work good from where I will be sitting. I can't sit farther back because this is going to be in my bedroom so the bed has to go somewhere. I will keep you guys updated.
 

Scott L

Senior HTF Member
Joined
Feb 29, 2000
Messages
4,457
My 4805 is at 80" and I sit about 9.5' away. Any closer would be uncomfortable. Screen door effect not bad at all.. but I can notice a tidbit when I look for it when text is on screen.

And I guess I'm not sensitive to rainbows cause I can't see any.
 

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