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post #1 of 20 Old 10-01-2017, 07:54 AM - Thread Starter
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Epson 3100 ceiling height

I'm looking at getting my first projector for a multiuse room. I am leaning towards the Epson 3100, but I'm having some trouble understanding the height from the ceiling.

Going off my limited knowledge of projector placement....The 3100 is zero offset but has +/-60% vertical lens shift. I'm planning on having the projector about 9' back from a 91" screen (Elite SPM91H-E12). Ceiling height is 8' and the screen will start somewhere around 2' from ceiling (12" top border, 3.5" case, chain hanging ~10" from ceiling). Nothing is hung yet as the room is still being built, so getting exact measurements is a little hard.

I did find the Epson calculator, but the lens shift checker confused me more than helping. Without using lens shift, it shows mounting the projector 4'2.5" from the ceiling. That doesn't work well in a mixed use room....so using the lens shift checker it says 2'2.8". What exactly does that mean? Is that saying I could use all of the lens shift and move my projector up 2'2.8" from the center position of 4'2.5"? This would be a little more doable as I could also adjust the screen up a few inches to get the projector above head knocking range.

I also ran across the Jack Liu calculator and it appeared to show mounting the projector at 19.7" from the ceiling.


Can someone help me out?
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post #2 of 20 Old 10-01-2017, 09:57 AM
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For a 91" screen the lens of the projector with lens shift maxed out it could be about 9" above to top of the screen. It also needs 8' 10" from the front of the lens to the screen with the zoom at its largest setting. I would give some leeway because tolerance errors may differ from specs. 91" by most of our standards is too small for true HT so put some thought into your screen size and make sure it will be big enough as it only has to satisfy you.

Last edited by rekbones; 10-01-2017 at 10:02 AM.
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post #3 of 20 Old 10-01-2017, 04:38 PM - Thread Starter
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Thanks for that information. How did you come up with 9" above the screen?
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post #4 of 20 Old 10-01-2017, 07:13 PM
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Quote:
Originally Posted by wilkija View Post
Thanks for that information. How did you come up with 9" above the screen?
The projector has a 0% fixed offset, in other words with the lens shift at its center point the center of the lens needs to be in the center of the screen, with +/- 60% shift, 50% would be half the screen height leaving 10% above the screen, 10% of 91" = 9.1 inches. In actual use their is a margin of error so test it first before making anything permanent.

Edit: sorry my bad that's 10% of 45 inches or 4.5 inches above the screen.

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post #5 of 20 Old 10-01-2017, 08:48 PM
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The +/- 60% vertical lens shift is referenced from the screen center.

If you have a 91" diagonal, 16:9 screen, the screen viewable height is ~45".

45" X .60 = 27"

So, for a ceiling mount, you should be able to mount the projector with reference to the lens center at a maximum of ~27" above the top of the viewable area of the screen.

You've indicated that you want to mount the top of the screen ~2 feet down from the 8 foot ceiling. So, the projectors lens center mounting position could be anywhere that it fits in that 24" from the top of the screen to the ceiling.

The Epson 3100 is listed as 6.2" high. I don't know what mount you want to use but figure 4-6 inches minimum for the mount height plus the projector and that places the bottom of the projector at ~7 feet from the floor. That leaves you plenty of vertical lens shift or in other words, you will not use all of the vertical lens shift available and it will maybe leave you enough room so you don't bump your head.
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post #6 of 20 Old 10-02-2017, 03:04 PM
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I have edited this post because my initial interpretation of the Epson projection calculator was incorrect. I've revised this to reflect an accurate interpretation thanks to input from other forum members in posts below:

There's a lot of confusion about how to measure lens shift, and @rekbones and @b curry have presented two different interpretations. Just to be sure I understood I checked the Epson projection calculator. When you enter the 3100 and a 91" diagonal 16:9 screen the Epson calculator verifies which interpretation is correct.

The calculator shows the projector even with a point on the vertical center of the screen, and with a full 60% vertical shift the image can be shifted up (or down) 60% of the image area's height. For example, a 91" 16:9 screen has an image area ~45" tall and 60% of 45" is ~27". So if you moved the projector up higher to a typical ceiling mount the lens would need to be centered on a point no higher than ~27" above the vertical center of the screen. Half of the screen's ~45" image height is ~22.5", and subtracting that from ~27" means the 3100's lens could be vertically centered no higher than ~4.5" above the top of the 91" screen's image area as @rekbones noted.

So for future reference 60% vertical lens shift refers to 60% of total screen image area height above the center and not the top of the image area.

files.support.epson.com/pdc/eai/flash/Index.html

Last edited by Dave in Green; 10-03-2017 at 09:11 AM.
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post #7 of 20 Old 10-02-2017, 07:48 PM
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I looked at the Epson's web site and using its lens shift calculator I seriously doubt it can be placed 26.5 inches above the top of the screen. It only shows a graphic of the shift area but it appears it can only be slightly above the top or slightly below the bottom assuming you are using no horizontal shift. If some one with a 3100 could post real world measurements it would help to solve this.
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post #8 of 20 Old 10-03-2017, 06:26 AM
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Quote:
Originally Posted by rekbones View Post
I looked at the Epson's web site and using its lens shift calculator I seriously doubt it can be placed 26.5 inches above the top of the screen. It only shows a graphic of the shift area but it appears it can only be slightly above the top or slightly below the bottom assuming you are using no horizontal shift. If some one with a 3100 could post real world measurements it would help to solve this.
Sure it can.

For a 91" 6:9 screen, it can be mounted anywhere between screen center, the 0 point, and the maximum of 60% up or down.

In the OP's case wanting to hang the screen ~24" from the ceiling, he will not be able or need to use the full maximum. But it's still there.

Not sure what your looking at referencing the graphic as the graphics on both of Epson's calculators, the Flash version and the HTML5 version support the 60% vertical shift of ~27" rounded.

You seem to be suggesting that it has a 10% fixed off set or lens shift maximum referencing 10% of 45" as 4.5" would be a 10% lens shift.

The HC 3100 is very flexible with regards to mounting.
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post #9 of 20 Old 10-03-2017, 07:14 AM
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Quote:
Originally Posted by rekbones View Post
I looked at the Epson's web site and using its lens shift calculator I seriously doubt it can be placed 26.5 inches above the top of the screen. It only shows a graphic of the shift area but it appears it can only be slightly above the top or slightly below the bottom assuming you are using no horizontal shift. If some one with a 3100 could post real world measurements it would help to solve this.
That's because their calculator (mostly) sucks. I have a huge issue with how lens shift calculators are shown. In the case of the 3100, the neutral position of the lens (no offset) is at 0% above/below the center line of the screen. So, the 26.5" is above the center line, not above the top of the screen.

I think this is, by far, the first calculator I've seen which is actually straightforward to use for lens shift inclusion:
http://www.reviewtranslations.com/pr...ulator_en.html

You put in the room height and the model of the projector and image diagonal, then you can just get the measurements you are after. You can move the projector up and down, move the lens shift around, and you can see it all happen and get real measurements! So, with a 91" diagonal, and the proejctor about 9' from a screen that is exactly 24" from the ceiling, the center of the lens must be 19.7" from the top of the ceiling (or more) and exactly on center. I would shoot to put the lens closer to 22" from the ceiling for a bit of flexibility.

Compared to this line of junk... https://files.support.epson.com/pdc/...ml5/index.html

I have book marked that new calculator, and encourage people to use it when they start needing to play with lens shift. Plus, the guy is a forum member which means we can give him some feedback. He was quick to add imperial (inches) to a previously metric only chart.

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post #10 of 20 Old 10-03-2017, 09:09 AM
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My initial interpretation of the Epson projection calculator was flawed so I just went back and revised my previous post. Apologies for the confusion and thanks to those who pointed out my error. It's confusing enough for newcomers to try to figure this out without those of us with more experience further muddying the issue.
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post #11 of 20 Old 10-03-2017, 10:50 AM
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Are you using a dark room? I just installed a 3100 about 11.5 feet away from a 92" screen and it is bright even in eco mode. I am getting used to it and have ordered an ND2 filter to try out but just wanted to let you know.

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post #12 of 20 Old 10-03-2017, 12:58 PM
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Quote:
Originally Posted by AV_Integrated View Post
That's because their calculator (mostly) sucks. I have a huge issue with how lens shift calculators are shown. In the case of the 3100, the neutral position of the lens (no offset) is at 0% above/below the center line of the screen. So, the 26.5" is above the center line, not above the top of the screen.

This is correct. I agree.

In my first post, I can see where my verbiage is confusing. I start out referencing screen center but then talk about lens center and the top of the screen.

Quote:
Originally Posted by b curry View Post
The +/- 60% vertical lens shift is referenced from the screen center.

If you have a 91" diagonal, 16:9 screen, the screen viewable height is ~45".

45" X .60 = 27"

So, for a ceiling mount, you should be able to mount the projector with reference to the lens center at a maximum of ~27" above the top of the viewable area of the screen.

You've indicated that you want to mount the top of the screen ~2 feet down from the 8 foot ceiling. So, the projectors lens center mounting position could be anywhere that it fits in that 24" from the top of the screen to the ceiling.

The Epson 3100 is listed as 6.2" high. I don't know what mount you want to use but figure 4-6 inches minimum for the mount height plus the projector and that places the bottom of the projector at ~7 feet from the floor. That leaves you plenty of vertical lens shift or in other words, you will not use all of the vertical lens shift available and it will maybe leave you enough room so you don't bump your head.
The bold line should read: So, for a ceiling mount, you should be able to mount the projector with reference to the lens center/screen center at a maximum of ~27". I referenced the top of the viewable area so as to not include the screen frame.
Sorry my F-up.



Quote:
Originally Posted by AV_Integrated View Post
I think this is, by far, the first calculator I've seen which is actually straightforward to use for lens shift inclusion:
http://www.reviewtranslations.com/pr...ulator_en.html

You put in the room height and the model of the projector and image diagonal, then you can just get the measurements you are after. You can move the projector up and down, move the lens shift around, and you can see it all happen and get real measurements! So, with a 91" diagonal, and the proejctor about 9' from a screen that is exactly 24" from the ceiling, the center of the lens must be 19.7" from the top of the ceiling (or more) and exactly on center. I would shoot to put the lens closer to 22" from the ceiling for a bit of flexibility.

Compared to this line of junk... https://files.support.epson.com/pdc/...ml5/index.html

I have book marked that new calculator, and encourage people to use it when they start needing to play with lens shift. Plus, the guy is a forum member which means we can give him some feedback. He was quick to add imperial (inches) to a previously metric only chart.
While the Epson HTML5 calculator may not be as intuitive as the JACK LIU Projection Calculator, it gives you what you need and it does give you additional information in regards to lens shift that the Jack Liu calculator does not.

As it's not typically possible to use the full range of both vertical and horizontal lens shift together, the Epson HTML5 version does give you a very good tool and reference to this point. If you enter the information correctly and completely on the first screen and click on the gray box "Lens shift checker", you will get a pop-up screen with your screens viewable area superimposed on a highlighted octagonal area that represents the screens total mounting area based on both the horizontal/vertical lens shift extremes as well as combinations of both horizontal/vertical lens shift.

You're able to drag the screen to any position inside the highlighted area and get instant corresponding values indicated for both the horizontal/vertical lens shift.

The truncated corner areas of the mounting rectangle coincide with and indicate the limitation of using both horizontal/vertical. The "cross-hairs" indicate the screen center but they also give you some indication of what part of the lens the panel image is projected through.
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post #13 of 20 Old 10-03-2017, 01:53 PM
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Quote:
Originally Posted by b curry View Post
The truncated corner areas of the mounting rectangle coincide with and indicate the limitation of using both horizontal/vertical. The "cross-hairs" indicate the screen center but they also give you some indication of what part of the lens the panel image is projected through.
I wonder if we can pass that on to Jack? He may be open to the idea of incorporating both lens shifts at once and a grid/map like that into his calculator. There are a few things which he can improve upon, IMO, but he's open to requests, which is just ultra-cool.

Imagine getting the 'perfect' calculator? That's a heck of a concept.

I do like that Epson includes the left/right option, but I'm totally diggin' the JL calculator right now as a straightforward option for the most popular models.

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post #14 of 20 Old 10-03-2017, 03:07 PM
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The more graphical a projection calculator is the more usable it will be for those who are less technically oriented. I can see now that Epson's HTML5 version is even better than their flash version because of the graphical lens shift checker that you can drag around and get shift measurements to pop up. This will be more intuitive for more people to use.
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Thanks for all of the input. Can anyone recommend a projector (similar quality/price) that I would be able to mount closer to the ceiling? Or a tool that allows to search projectors on those parameters?
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post #16 of 20 Old 10-03-2017, 04:39 PM
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Quote:
Originally Posted by wilkija View Post
Thanks for all of the input. Can anyone recommend a projector (similar quality/price) that I would be able to mount closer to the ceiling? Or a tool that allows to search projectors on those parameters?
Well you could go with an Epson HC5040UB or HC4000. They are both listed as having +/- 96% vertical lens shift. So an extra 36% over the HC3100. But then they're approximately double the price.

The problem is, more lens shift means bigger glass and bigger glass means more money. A lens has a sweet spot where the color, focus, absence of aberrations are minimized. Lens shift exploits the lens sweet spot . So for a given panel/image size, you need a larger lens area to increase the shift % and allow the lens to keep a good image. It's why low cost projectors don't usually have lens shift as the lens to support it will increase the cost of the projector.

You could maybe consider moving the screen a little higher and kind of split the difference between the projector and the screen. Or, go with a bigger screen. A bigger screen would increase the screen height, getting the projector closer to the celing while keeping the screen center the same for you seating position. a 100" screen would increase screen height ~2.2" from center while giving you the same screen center as your 91" mounted 24" from the ceiling.
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post #17 of 20 Old 10-03-2017, 04:51 PM
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Quote:
Originally Posted by AV_Integrated View Post
I wonder if we can pass that on to Jack? He may be open to the idea of incorporating both lens shifts at once and a grid/map like that into his calculator. There are a few things which he can improve upon, IMO, but he's open to requests, which is just ultra-cool.

Imagine getting the 'perfect' calculator? That's a heck of a concept.

I do like that Epson includes the left/right option, but I'm totally diggin' the JL calculator right now as a straightforward option for the most popular models.
I don't see why not. OTOH I think he would need more specific information about a particular lens and I'm not sure how he would get that information short of just copying the measurements from Epson which is what it appears he's already done for the vertical shift feature of his calculator.
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post #18 of 20 Old 10-03-2017, 07:56 PM
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Quote:
Originally Posted by wilkija View Post
Thanks for all of the input. Can anyone recommend a projector (similar quality/price) that I would be able to mount closer to the ceiling? Or a tool that allows to search projectors on those parameters?
You might be able to find a Epson 5030 manufacture referbished for about the same price, or even used but I don't recommend used to a new user unless you don't mind gambling because if it fails without warranty they generally aren't worth fixing.

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post #19 of 20 Old 10-04-2017, 12:15 AM
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Quote:
Originally Posted by b curry View Post
I don't see why not. OTOH I think he would need more specific information about a particular lens and I'm not sure how he would get that information short of just copying the measurements from Epson which is what it appears he's already done for the vertical shift feature of his calculator.
Request received

Information needed can all be got from projector's user manual (Ver xx%, Hor xx%, etc.).

As I mentioned in my reply to AV_Integrated in the other thread, the hard part is how to present the horizontal shift control in an intuitivfe way.
Current JACK LIU Projection Calculator is considered intuitive to use, and I want to keep it that way.
So let me think it very carefully before implementation.

Thanks for the feedback!

Jack

JACK LIU Projection Calculator - Zoom + Lens Shift at the same time
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post #20 of 20 Old 10-04-2017, 06:06 AM
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Quote:
Originally Posted by dupin67 View Post
Request received

Information needed can all be got from projector's user manual (Ver xx%, Hor xx%, etc.).

As I mentioned in my reply to AV_Integrated in the other thread, the hard part is how to present the horizontal shift control in an intuitivfe way.
Current JACK LIU Projection Calculator is considered intuitive to use, and I want to keep it that way.
So let me think it very carefully before implementation.

Thanks for the feedback!

Jack
Yes, the % shift values factored from a given screen size and aspect ratio plotted on an XY grid. The truncated area seems to be a tangent of the % shift value maximums from screen center. Just thinking out loud, as all projectors do not have horizontal shift, a simple pop up as Epson has done maybe the best way.
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