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The Official Acer H9500BD Thread - Page 134

post #3991 of 4744
@ aaranddeeman

Let me ask a simple question to clarify, are you guys saying the projector's lens can be placed below the top of the screen?
According to my calc, the minimum offset is about 2.8" for a 110" screen, this means the closest the projector can be placed to the top of the screen is with the lens about 3" above it for a 110".
For a 92" screen this becomes about 2" above the top of the screen (remember it goes by center of the lens, not bottom of the projector). As noted, my PJ calculator has a bug where it shows the graphics incorrectly, it only does it on a couple projectors (the Acer is one), so look at the offset and not the graphic. I had fixed this bug in a previous version, but somehow I messed it up again. I will release a new version of the calculator soon enough, just busy at work lately. If that minimum offset value is correct in my calculator, then I'm guessing that the max. offset is not that far off either (unless the Acer manual goofed).
Edited by coderguy - 9/13/12 at 10:43am
post #3992 of 4744
Quote:
Originally Posted by InCali View Post

At 10.5 feet with full zoom, the picture size will be about 93". The height is fine. If you want a bigger picture, you'll have to move back some. Coder's calculator is pretty accurate (or was with my PJ) in this regard.

Oops, I typed that wrong. There is a 11.5 inch vertical offset. My screen is 92" diagaonal so I do plan to use the full zoom or close to it. I use the full zoom on my MIts and that is to increase brighness since my room is not very "light-controlled". I realize 92" is kinda on the small size for projection but I can't go much bigger in my setup.
post #3993 of 4744
Quote:
Originally Posted by KillRob View Post

Oops, I typed that wrong. There is a 11.5 inch vertical offset. My screen is 92" diagaonal so I do plan to use the full zoom or close to it. I use the full zoom on my MIts and that is to increase brighness since my room is not very "light-controlled". I realize 92" is kinda on the small size for projection but I can't go much bigger in my setup.

I don't think that's small. You are correct that the closer you have the PJ, the brighter the picture. You're right on the edge, but will probably be okay. These PJ are not all created equal so you won't know for sure until you mount it.
post #3994 of 4744
Quote:
Originally Posted by coderguy View Post

@ aaranddeeman
Let me ask a simple question to clarify, are you guys saying the projector's lens can be placed below the top of the screen?
According to my calc, the minimum offset is about 2.8" for a 110" screen, this means the closest the projector can be placed to the top of the screen is with the lens about 3" above it for a 110".
For a 92" screen this becomes about 2" above the top of the screen (remember it goes by center of the lens, not bottom of the projector). As noted, my PJ calculator has a bug where it shows the graphics incorrectly, it only does it on a couple projectors (the Acer is one), so look at the offset and not the graphic. I had fixed this bug in a previous version, but somehow I messed it up again. I will release a new version of the calculator soon enough, just busy at work lately. If that minimum offset value is correct in my calculator, then I'm guessing that the max. offset is not that far off either (unless the Acer manual goofed).

I'm not saying that. I have my lens center 3" "above" the top of the viewable area of the screen (120"). I "think" I have upward shift, but don't know for sure. I'll check when I get back home and let you know how much up and down I have. I'm not dead center horizontally to the screen (that's partially why I got the Acer) so the side to side won't really help (I suppose I can make those measurements also). I should be pretty much dead level vertically (and horizontally for that matter), but will double check and get back to you. I'll recheck all my measurements and get them to you.
post #3995 of 4744
Quote:
Originally Posted by Mikes2cents View Post

Very well. PM me the instructions and equipment (where to get) and I will be happy to oblige.

Edit: OK see the link to the meter.smile.gif I will get back to you on the 3D ISO files.

sounds good mike, let me know. the file is only 250 megs or so, but it has the important 100% IRE screen in 3D frame packed mode so we can get an accurate measurement in 3D mode.
post #3996 of 4744
Quote:
Originally Posted by coderguy View Post

@ aaranddeeman
Let me ask a simple question to clarify, are you guys saying the projector's lens can be placed below the top of the screen?

No.

My PJ bottom (the actual bottom that will face the ceiling when mounted) to ceiling distance is about 12.5". That makes the lens center about 15.5"
The viewable top of my screen is at 19.25". So that makes it about 3.75" below lens center. I can not shift the lens anything above (may be just a little bit like few mm) such that the viewing top can move towards ceiling.
Hope I am making any sense..
post #3997 of 4744
So are you saying 3.75" below the lens center is just as far as you can move the image up towards the lens?

Keep in mind if you can move the image down, then that means you can create more offset and that is generally inline with what the calculator reports... It is not expected that you would be able to move the image up much, because moving the image up is moving it back toward's the lens, and that would be the minimum offset which would theoretically be 2" to 4" (give or take MFR error). That said, my calculator would still be off by about 1.5 inches if I understand you correctly, and I can make that adjustment. However, if I am interpreting what you are saying backwards, then that would make my calc way off.

To explain further, when you are moving the lens shift in my calculator program, it is re-positioning the projector, so it is just showing you the FULL mounting range given a screen size and screen distance setup if you are willing to re-position the mounting of the projector, whereas some calculators are showing the opposite (the lens shift range given a fixed mounting position). Hence, my calculator is not meant to show you the lens shift range from a fixed mounting position, it is showing you the FULL range of anywhere you can mount the projector and still meet the screen dimensions.

In the first version, I actually contemplated designing it the other way, that is to show a fixed lens shifting range, but it made it so that no-one could see all mounting spots, so I determined the latter was much better as it allows people to see all mounting positions that are possible given where they set the screen up at.
Edited by coderguy - 9/14/12 at 10:58pm
post #3998 of 4744
Quote:
Originally Posted by coderguy View Post

So are you saying 3.75" below the lens center is just as far as you can move the image up towards the lens?

Yes that is about right. I can not move the lens anymore such that the image can move upwards towards ceiling.

Quote:
Keep in mind if you can move the image down, then that means you can create more offset and that is generally inline with what the calculator reports...

Yes, I can go down. i.e. move image towards the floor.

Quote:
It is not expected that you would be able to move the image up much, because moving the image up is moving it back toward's the lens, and that would be the minimum offset which would theoretically be 2" to 4" (give or take MFR error).

I am lost with your words when you say back toward's the lens
post #3999 of 4744
I edited my post above, re-read it. It is a bit complicated, but I think the confusion is that you thought the calculator was trying to show you where the lens shift range is from a fixed mounting spot, but the calculator is not showing that, it is showing all the possibilities of where you can mount the projector given the entered screen position (screen size, screen distance from ceiling, etc...). Hence, the calculator is generally correct within a couple inches based on what you are reporting, and I suppose I could add another inch to the minimum offset, but I am thinking this 1" to 1.5" discrepancy may be an alignment issue or MFR tolerance, because I am pretty sure I got that minimum offset directly from the manual.
post #4000 of 4744
Quote:
Originally Posted by coderguy View Post

So are you saying 3.75" below the lens center is just as far as you can move the image up towards the lens?
Keep in mind if you can move the image down, then that means you can create more offset and that is generally inline with what the calculator reports... It is not expected that you would be able to move the image up much, because moving the image up is moving it back toward's the lens, and that would be the minimum offset which would theoretically be 2" to 4" (give or take MFR error). That said, my calculator would still be off by about 1.5 inches if I understand you correctly, and I can make that adjustment. However, if I am interpreting what you are saying backwards, then that would make my calc way off.
To explain further, when you are moving the lens shift in my calculator program, it is re-positioning the projector, so it is just showing you the FULL mounting range given a screen size and screen distance setup if you are willing to re-position the mounting of the projector, whereas some calculators are showing the opposite (the lens shift range given a fixed mounting position). Hence, my calculator is not meant to show you the lens shift range from a fixed mounting position, it is showing you the FULL range of anywhere you can mount the projector and still meet the screen dimensions.
In the first version, I actually contemplated designing it to show a fixed lens shifting range, but it made it so that no-one could see all mounting spots, so I determined the latter was much better as it allows people to see all mounting positions that are possible given where they set the screen up at, that is why it is important to enter the position of the screen into my calculator correctly.

BTW, I am waiting for my PJ that is expected to arrive today from Acer after the updates.
This time I am going to swap the mount position. (I have 2 PJs mounted, Another being Sanyo).
I can get you new numbers from a different reference point. The throw distance at new position is approx 11ft 1in. And the ceiling to PJ bottom would be about 6.5". Rest all remains the same (screen size and position) as mentioned in the PM.
post #4001 of 4744
It would not surprise me if the manual is off in the throw distance, almost all the PJ manuals are off here. I think the lens shift numbers I have in there are ballpark accurate, but the throw I don't know. So yes if you can give me the minimum and maximum throw distance at a given screen size and mounting position, then I will correct the throw.

For instance, on JVC projectors, the MFR claims the minimum throw is 1.4, but it is really 1.37 and this means people can mount their projectors a little closer than what JVC claims, and I'd say almost half the time the manuals have the throw WRONG (which is basically how big of a picture you can get at MAX ZOOM)...
post #4002 of 4744
Quote:
Originally Posted by coderguy View Post

How big is the screen, the screen size (specifically screen height) is what determines vertical offset and lens shift amount.
If the Acer has a more off-balance vertical lens shift control, then I'll have to re-enter all the numbers into my calculator. None of the reviewers said it did, but I have not had anyone measure it exactly and report back to me. Projector calculators are generally just a guideline as there are also MFR tolerances and errors in the default specs that can vary slightly between units (but usually not more than an inch or two). I used the numbers provided by the manual and read all the reviews in an attempt to get the lens shift values correct. Do note that my calculator does have a graphical bug (it shows the projector in the wrong position sometimes graphically, but do not look at the graphics, look at the OFFSET value)...
If someone wants to precisely measure this and is confident in their abilities to understand lens shift and confident they have the projector perfectly level (with zero PJ tilt), then I can update the calculator with corrected numbers. I did look at aaranddeeman PM he sent me, but I need exact measurements to know for sure.

Curiosity got the better of me so I decided to work from home this afternoon (Since I'm in IT, I figured "Why not?"). Here are my "stats":
120" screen
Lens to Screen - 14'
Center of Lens is 3 1/2 " above the top of the viewable area of the screen (the change from 3" is probably due to the fact that the screen has been rolled up and I adjusted the PJ afterwards)
Vertical shift is about 5" up and down
Center of lens is 8" to the left of the center of the screen (looking at the screen)
Horizontal shift is 16" to the left and about 4" to the right

Judging by sight and lack of keystone, I think the projector (vertical and horizontal) is pretty much square to the screen (90 degrees V and H).

Edit - Correction....upon further inspection, it was tilted up ever, ever so slightly. After making it perfectly level (then raising the vertical adjust). I now have about 2" upward adjust left. That, by inference, gives me about 8" downward adjust.

How does that square with your calculator? For image size and mounting, I've found it to be pretty doggone good.

BTW, I have NO idea why they call this vertical and horizontal adjust. They should call it "diagonal adjustments". This can "seriously" complicate trying to figure out the vertical adjustment range (especially) if you are off center horizontally. As you adjust "horizontally" the picture goes up or down by (at least) a few inches. I'm sure the same can be said about the lens offset and horizontal adjustment range.
Edited by InCali - 9/13/12 at 12:51pm
post #4003 of 4744
That would be within the realm of what the calculator shows within about 1" on the allowable lens shift, however do keep in mind that the only way to get an accurate measurement for the calculator is if the LENS is centered exactly horizontally to the center of the screen. This is because my calculator does not do horizontal lens shift (I may eventually way down the road, but this gets really complicated because of errors in most manuals really can throw off the horizontal lens shift). Once anyone has used any horizontal lens shift, this will change the parameters of the allowable vertical lens shift and offset as well (something my calculator cannot currently take into account).

Also, even a screen that has the "ever so slightest" and almost invisible alignment issue can explain a 1" to 2" minimum offset discrepancy. It is difficult to get it accurate on the lens shift within that last 1" or 2", as people will often believe they have their projector aligned properly but 1" is easy to be off as the amount of angle to create 1" of extra offset is not visible by eye, you must use a level and know how to do it.
post #4004 of 4744
Quote:
Originally Posted by coderguy View Post

That would be within the realm of what the calculator shows within about 1" on the allowable lens shift, however do keep in mind that the only way to get an accurate measurement for the calculator is if the LENS is centered exactly horizontally to the center of the screen. This is because my calculator does not do horizontal lens shift (I may eventually way down the road, but this gets really complicated because of errors in most manuals really can throw off the horizontal lens shift). Once anyone has used any horizontal lens shift, this will change the parameters of the allowable vertical lens shift and offset as well (something my calculator cannot currently take into account).
Also, even a screen that has the "ever so slightest" and almost invisible alignment issue can explain a 1" to 2" minimum offset discrepancy. It is difficult to get it accurate on the lens shift within that last 1" or 2", as people will often believe they have their projector aligned properly but 1" is easy to be off as the amount of angle to create 1" of extra offset is not visible by eye, you must use a level and know how to do it.

See my BTW edit on previous post. Yet another factor.....
post #4005 of 4744
Yah, as you use horizontal adjustment you lose vertical play in the lens shift as well, all projectors are like that. On many projectors, it will be something like for every 1" you use of horizontal lens shift, you lose twice as much vertical lens shift. So if you need to move the image over say 6" or more, then you may lose nearly all your vertical lens shift capabilities (but each projector varies on this). This stuff can be confusing, especially given that my calculator has that graphical placement bug which makes it even more confusing. I mean it is not simple to think of the calculator in terms of "where I can mount the projector" rather than in terms of "how far can I move the lens shift".

The end goal on the calculator was to fix the graphical bugs, create a video tutorial, and to clean it up a bit, and eventually I will get to it. Also I am creating a clearance calculator section so people can see where the projector's beam is in relation to furniture and peoples' heads, but that is for another day.
post #4006 of 4744
Quote:
Originally Posted by coderguy View Post

Yah, as you use horizontal adjustment you lose vertical play in the lens shift as well, all projectors are like that. On many projectors, it will be something like for every 1" you use of horizontal lens shift, you lose twice as much vertical lens shift. So if you need to move the image over say 6" or more, then you may lose nearly all your vertical lens shift capabilities (but each projector varies on this). This stuff can be confusing, especially given that my calculator has that graphical placement bug which makes it even more confusing. I mean it is not simple to think of the calculator in terms of "where I can mount the projector" rather than in terms of "how far can I move the lens shift". It could even confuse me for a second if I wasn't the one that designed the thing. I just didn't like the alternative method because when trying to figure out where to put the screen it makes it even more confusing.

My LCD (Sanyo Z2000) was pretty good actually. It kind of surprised me when I tried to use the "horizontal/vertical" shift on the Acer. Basically, with all the factors involved, it's impossible to do anything other than ballpark the shift....impossible.....
post #4007 of 4744
Yup, LCD projectors just have so much freaking play, and the Sanyo had one of the largest amount of lens shift available. You could pretty much put the Sanyo anywhere in the room and it'd still have enough shift left over, but only the Epson and Sanyo LCD's (and Panny somewhat) are like that. Next we have the JVC's and Sony LCOS's, those are not as placement flexible as the Epson or Sanyos were, but they are better than DLP's.
post #4008 of 4744
Quote:
Originally Posted by coderguy View Post

Yah, LCD projectors just have so much freaking play, and the Sanyo had one of the largest amount of lens shift available. You could pretty much put the Sanyo anywhere in the room and it'd still have enough shift left over, but only the Epson and Sanyo LCD's (and Panny somewhat) are like that. Next we have the JVC's and Sony LCOS's, those are not as placement flexible as the Epson or Sanyos were, but they are better than DLP's.

When I replaced my Sanyo (gave it to my son really), I needed something with "some" lens shift and it's why I bought the Acer. With the Sanyo, I could practically watch a movie on the wall to my right (okay....an exaggeration). While it did have a HUGE shift, I was really commenting on the fact that horizontal basically meant horizontal and vertical basically meant vertical. I've only had the two projectors and was very surprised by the diagonal shift of the Acer. It works though so WTH......

Starting tomorrow, I'm on a 2 week vacation to my old haunts in Santa Cruz. I'll be bumming around Steamer's, other beaches, and Mexican restaurants (well, those with tequila anyway.....). I'll be checking in, but won't be on my laptop 24/7 as usual. My responses to PMs will probably be delayed until I'm semi-coherent (ie not very often) or on land (ditto).
post #4009 of 4744
Just don't slosh too many down and then go driving on the Pacific Coast Highway...
I've been to San Fran and Monterey and San Jose, but never quite all the way to Santa Cruz.

A lot of really great sea food in Monterey and San Fran, although I spent way too much on food when I was in San Fran (don't remind me). I remember the restaurants in Monterey on the coast (like 30+ in that one area), but it's been almost 10 years ago. Mexican food is ok, we get a lot of it here in Texas, but like anything I can only eat it now and then.
post #4010 of 4744
Quote:
Originally Posted by InCali View Post

I'll check it out. So, your PJ shutdown completely (no red power light.....no nothing)?
Sorry for the late reply. Yes just like you unplugged it from the power outlet. The first time it failed the light power light was on and all I had to do was power on with the remote again. It could have been 2 different problems but it hasn't done it anymore since the lamp cover was replaced. Knock on wood:)smile.gif. I argued with Acer support to just ship me the door to no avail.
post #4011 of 4744
Quote:
Originally Posted by coderguy View Post

If someone wants to precisely measure this and is confident in their abilities to understand lens shift and confident they have the projector perfectly level (with zero PJ tilt), then I can update the calculator with corrected numbers. I did look at aaranddeeman PM he sent me, but I need exact measurements to know for sure.
I thought I already did that for you when I first got the projector? Before ceiling mounting the unit I tested many things. Just so you know I measured the shift by first zooming to the screen and centering the projector to the screen with zero lens shift. Then I measured the shift up and down and then checked the effect with a combination of both. You must have forgotten the post based on your question or doubt my abilities but I did that at your request and to help potential buyers.

Anyways, here is part of my post from 01/25/12:
Quote:
In my boring measurement exercise I noted that the 5% offset is about right but the lens shift numbers are far less. I noted that there was a max of about 13" horizontal shift with zero vertical and surprisingly less vertical shift at about 11" with zero horizontal shift. That is nothing like the manual says with my particular unit so beware if you need a greater offset. If you are counting on anything greater than about 14" of offset you may be taking a chance based on what I saw. I was easily able to obtain a 120" image at about 13' 3" of throw. I will not be testing max throw because of a wall.
I got no further questions and saw no need to test further for my application.
Now I am watching da Bears and Packers on the 9500. Lookin good.
post #4012 of 4744
Quote:
Originally Posted by InCali View Post

Starting tomorrow, I'm on a 2 week vacation to my old haunts in Santa Cruz. I'll be bumming around Steamer's, other beaches, and Mexican restaurants (well, those with tequila anyway.....). I'll be checking in, but won't be on my laptop 24/7 as usual. My responses to PMs will probably be delayed until I'm semi-coherent (ie not very often) or on land (ditto).
Have a great vacation and don't worry about this thread. It is a thread about a projector we own but aside from that nothing more. I am tired of defending this projector and have decided my focus is more on enjoying it. If you are RBE sensitive, do not get this unit and get a LCD unit with convergence and softer image. Not going to argue this crap any more as I have both. I am more than satisfied with my experience with the unit and Acer's support although the firmware update could have come about quicker.

Back to my point though, being incoherent never stopped me from posting though somehow I wish something had at times.wink.gif Enjoy your time off.
post #4013 of 4744
I have just got through chatting with tiger direct and was told they were not going to carry the acer H9500BD anymore. Only place that seems to carry it now is New Egg.
post #4014 of 4744
Quote:
Originally Posted by bobwaldo View Post

I have just got through chatting with tiger direct and was told they were not going to carry the acer H9500BD anymore. Only place that seems to carry it now is New Egg.
Well it was discontinued on Egg for a while too. Guess we will just have to wait and see. I bet the unit will be selling at a very attractive price before too long but do not know how long that will be since I do not see a replacement for it this year yet. Let us not forget how long Acer ran the 5360 which was the defacto 3D projector of its' time.
post #4015 of 4744
May I ask anyone to test the input lag in 3D mode, in games? (both 720p60 framepacking and 1080p side-by-side)

Is it still too high with the B03 firmware? Please?
post #4016 of 4744
Firmware isn't likely to change input lag on any projector, it almost never does (if ever).

If someone wants to measure their PJ, you have to measure BOTH MIN and MAX zoom/throw and measure the screen size you are getting in those positions at an exact given distance from the screen. So far the measurements I've seen are "abouts" or "looks like" or are incomplete, so the answer is NO -- so far no-one has provided proper measurements. If someone wants to measure it properly, PM me and I will help them. Providing me one min or max zoom measurement also does no good, because a throw ratio cannot be calculated from that.

As far as the lens shift, let's put this to rest. For 120" screen, the calculator shows 11" of vertical lens shift play (14" max offset, 3" min), and this is with ZERO horizontal (as always), so the measurements keep getting questioned, but nothing posted by anyone disagrees other than people misinterpreting what the calculator is showing. As far as I recall, these values agree with the way I interpreted the manual which is where my data came from, and no-one's data in here is actually disagreeing with the manual if the manual is interpreted properly (as far as I recall). When you move the projector in my calculator (up or down), you are changing the mounting position away from the screen as the basis position, you are not changing lens shift by itself. Sorry if I sound frustrated, but this issue keeps coming back up like every month or two and some are perpetually saying it is off, but it is just being misunderstood. So I see no reason not to trust the calculator's lens offset numbers (just don't trust the graphic, the graphic is bugged a little but the numbers are correct, I will try to re-fix the graphical bug in a moment).

As noted previously, the calculator is only showing potential mounting positions from the screen position as the basis, not the different positions that lens shift can move the image from a fixed mounting spot. By showing mounting positions, it does also show the lens shift range in the sense of numerical min/max but not from a fixed mounting position. Instead it is showing you the ENTIRE choice of areas where you can mount the projector and still hit the screen properly given how you entered the screen parameters. I know this concept can be confusing, but I do not know how many different ways I can explain it. This is why people keep questioning the lens shift values. To avoid confusion, just set the screen position parameters and screen size first and then just look at all potential mounting spots.

There is no reason for me to show how far you can move the image off the screen unless I also make the screen move at the same time, and that is even more confusing IMHO. If the concept is still not understood, try Epson's calculator for the 8700ub and you will see what I mean, that one uses the opposite method (screen moves and lens shift moves). That other method used by Epson's calculator works so-so for one type of lens shift, but my calculator has to cover all types (center-based, non-center, DLP, LCD, etc...).
Edited by coderguy - 9/14/12 at 10:07pm
post #4017 of 4744
Note to self:
Add above link to notepad so the next time the same question is asked I can refer people to that post...

2nd Note to Self:
Task in first "Note to self" now completed...
Edited by coderguy - 9/14/12 at 10:52pm
post #4018 of 4744
Quote:
Originally Posted by coderguy View Post

If someone wants to measure their PJ, you have to measure BOTH MIN and MAX zoom/throw and measure the screen size you are getting in those positions at an exact given distance from the screen. So far the measurements I've seen are "abouts" or "looks like" or are incomplete, so the answer is NO -- so far no-one has provided proper measurements. If someone wants to measure it properly, PM me and I will help them. Providing me one min or max zoom measurement also does no good, because a throw ratio cannot be calculated from that.
As far as the lens shift, let's put this to rest. For 120" screen, the calculator shows 11" of vertical lens shift play (14" max offset, 3" min), and this is with ZERO horizontal (as always), so the measurements keep getting questioned, but nothing posted by anyone disagrees other than people misinterpreting what the calculator is showing. As far as I recall, these values agree with the way I interpreted the manual which is where my data came from, and no-one's data in here is actually disagreeing with the manual if the manual is interpreted properly (as far as I recall). When you move the projector in my calculator (up or down), you are changing the mounting position away from the screen as the basis position, you are not changing lens shift by itself. Sorry if I sound frustrated, but this issue keeps coming back up like every month or two and some are perpetually saying it is off, but it is just being misunderstood. So I see no reason not to trust the calculator's lens offset numbers (just don't trust the graphic, the graphic is bugged a little but the numbers are correct, I will try to re-fix the graphical bug in a moment).
First of all I do not believe I ever said your calculator was wrong (not that you are saying that). A lot of factors come into play with this lens shift and throw distances including tolerances from unit to unit and measurement precision. Therefore we get the plus minus disclaimers. My disclaimer was that I said "about" this far or "about" that much shift at this (precise) screen size. You are right, it is very difficult to measure exactly how far the screen is from the lens and I would question any claim to this unless tested in a laboratory. As for perfect alignment horizontally and vertically, I could get close by throwing up a test screen and measuring pixel boxes in each quadrant of the screen with a micrometer, obviously, but this would result in a very good alignment as opposed to perfect. I did not do this.

So what we end up with in the real world is that my unit has about this much shift ability up and down at about this far from the screen which BTW is about 6" back from the minimum throw for a 120" screen. Potential buyers looking into this projector for their particular installation will be considering that they want to project from about this distance with about this much shift. Since no two units are identical and your calculator is pretty much in line with Acer's they can use that. I found that I got a bit less shift than advertised in my not quite precise measurments and that is what it is. My long belabored point here is that I urge people to use the calculators conservatively so they do not push the envelope and end up disappointed. Try to stick to a shift scenario utilizing just one of the shifts if possible and if you have to use some of both the shift becomes severely reduced and is almost impossible to measure properly due to the way the image moves when up against that limit. Probably the only way to properly obtain those numbers would be to plot a few measurements. I don't see anyone doing this and again recommend staying away from max shift type installation scenarios because of this. Also, buyers must understand that the vertical shift is only in one direction and that is away from the minimum offset. Nothing wrong with the calculators for this, I just urge people to be conservative using those figures.

Quote:
Originally Posted by zombie10k View Post

sounds good mike, let me know. the file is only 250 megs or so, but it has the important 100% IRE screen in 3D frame packed mode so we can get an accurate measurement in 3D mode.
My light meter has arrived and I am looking forward to testing the 2D lumens and 3D lumens delta. Snazzy term there eh?wink.gif

I want to be sure that I obtain the right data. Any clever people want to tell me which picture mode I should measure in 2D for a proper comparison to the 3D if I ever get that file working? I presume it should be the one closest to D6500 but without the means to measure this I suppose I should use settings from reviews that claim to get the closest to this? I welcome any input on this before I crank up the projector and stumble through this. Anything else I should measure or play with while fooling around with this meter? Oh, and I could google but what do you guys use to convert lux to lumens? I know we are primarily after the difference between 2D and 3D though. Thanks, I hope to get around to this today.
post #4019 of 4744
I can measure the throws and offset fairly exact, you just need a laser measure or to be very good with a tape measure, it is not that hard and does not need to be done in a lab (it is difficult for someone doing it half-hazard though and when people say "looks like" or "almost" then I cannot trust it obviously). Let's not act like people always were interpreting the manual correctly suddenly and that I am coming out of the blue here (there are like 30+ posts questioning the manual and calculator)... The post wasn't specifically directed at you, but we keep re-explaining this... Lens shift values in manuals are hard to interpret, even sometimes after reading 50+ manuals, the way I do it is I look at all the measurements and then I can throw out whatever part of the manual disagrees with itself (which is about 25% of all manuals). If the manual is interpreted correctly, it does not disagree with the numbers you posted for lens shift, but I have not checked the throw specifically unless someone measures it, so when people keep saying the manual is wrong, there is no evidence of that. The manual explains it unclearly, but it is not wrong thus far. I am not saying it is 100% perfect either, but am just saying thus far there is no evidence of it being incorrect until someone provides exact measurements which disagree (measurements provided thus far do not disagree, so I do not know why people keep saying they do).

I would note that it is fairly simple to be very slightly OVER even the minimum or max offset, and just let the screen border absorb tiny amounts of mounting error, so it should not be a problem to mount it near the maximum amount of shift. My Viewsonic is mounted 6" away under the minimum offset, although that is a bit extreme and does show some error, but doing it 1-2" away from the max is not visible if you do it properly. Using less lens shift might produce a slightly sharper image due to less chromatic aberration (but overall should not be that noticeable on most PJ's these days). This is why it is so hard to even differentiate between 1" to 2" of offset when measuring offset. One way to properly measure offset on a projector is by placing a piece of notebook paper in front of it and drawing the diameter of the lens on the paper, then measuring the distance of the paper to the lens, and then calculating the amount offset from the lens to the image projected (you do have to measure very carefully). That is if you want to be exact, then you repeat the measurement farther way on the screen and divide the error by 2 which reduces the error sampling down to minimal amounts and should be within 1/4" even at long distances.

Another option in dealing with offset, is if you have a fixed screen, you can put a board behind the screen and even gain much more mounting flexibility by slightly tilting the screen into the image to keep keystone unnecessary.
Edited by coderguy - 9/15/12 at 10:54am
post #4020 of 4744
Mike, here is how to calculate the lumens.

First calculate your screen size in Sq inches. I'll use my 142" 16:9 as an example.

Screen = 70" tall x 124" wide = 8680 Sq Inches. Convert this to SQ Meters.

http://www.metric-conversions.org/area/square-inches-to-square-meters.htm

8680 Sq inches = 5.59 Sq meters

Lumens = Sq Meters x Lux

The lux is measured at the center of the screen, with the meter as close to the screen as possible. Move it around for max output. This is a rough measurement, as you would need 9 measurements (top, bottom, corners, averaged to really calculate the lumen output, but this is good enough for now).

W7000 in 2D mode @ D65 = 5.59 Sq Meters x 268 Lux = ~1500 lumens

W7000 in 3D mode = 5.59 Sq meters x 196 lux = ~ 1100 lumens

This is at the shortest throw possible for the W7000.
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