Need help finding a projector with 0% lens offset - AVS Forum | Home Theater Discussions And Reviews
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post #1 of 19 Old 06-28-2020, 09:59 AM - Thread Starter
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Need help finding a projector with 0% lens offset

So I ordered a BenQ 3550 yesterday...but failed to consider the lens offset when I picked it. I'm building a small HT room, that has a ceiling fan that the wife says has to stay. I was ok with that and planned to mount projector on a shelf on the rear wall 5 feet up or so. I'm looking to use a 120" screen and the 3550 has a semi short throw so I was good there ( room is 11 x 13).

Everything I've looked at seems to be built for ceiling mounting and has 100% lens offset or more. I need something with 0%. I can't seem to find a way to search anyone's site for compatible options. Suggestions? Looking for 4K, with 3D and less than $2K. thanks.
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post #2 of 19 Old 06-28-2020, 10:13 AM
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The lens offset shouldn't be an issue if you can move the pj mount over a few inches on the shelf before securing it. I think Chief also makes a mount that allows for some horizontal movement. I have my Benq mounted under a shelf, along with unistrut channel and can move my mount over a few inches in either direction.
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post #3 of 19 Old 06-28-2020, 10:21 AM
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Maybe I'm not understanding your question, but all the projectors I've had can project straight ahead... the 100% offset up or down is just a maximum achieved by shifting the lens. Zero offset should give the best results since you're using the sweet spot of the lens.
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post #4 of 19 Old 06-28-2020, 10:22 AM
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I was in a similar situation. 13'8" x 20' and wanted to use the shorter side. I was considering the ht3550 as an upgrade to my w1070 but but decided on the epson 3200 since it was also a few bills cheaper than the benq refurb.

While it might be a very tight fit the epson 3200/3800 just might fit in there with a 11'6" minimum distance at that size. Would also give you more flexibility on placement. But... you will lose the dci-p3 color as it does only 78% (113% of 709) of it. But it's 3k lumens so it's a trade off. It's also heavier at 15lbs.

Also the 3550 has a small vertical lens offset from the top of the screen of 10% i believe which should put you at 0%. But there is no horizontal. The epson has +/- 60% vertical and 24% horizontal.



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post #5 of 19 Old 06-28-2020, 10:24 AM
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Quote:
Originally Posted by chiefp View Post
So I ordered a BenQ 3550 yesterday...but failed to consider the lens offset when I picked it. I'm building a small HT room, that has a ceiling fan that the wife says has to stay. I was ok with that and planned to mount projector on a shelf on the rear wall 5 feet up or so. I'm looking to use a 120" screen and the 3550 has a semi short throw so I was good there ( room is 11 x 13).

Everything I've looked at seems to be built for ceiling mounting and has 100% lens offset or more. I need something with 0%. I can't seem to find a way to search anyone's site for compatible options. Suggestions? Looking for 4K, with 3D and less than $2K. thanks.
If think you're confused about this projector's specifications.

There's no 0% offset. 100% offset means the center of the lens is at the same height as the bottom of the screen if the projector is on a table, and top of the screen if the projector ceiling mounted.

It only has a very small amount of vertical lens shift, which is noted at the bottom of the calculator page after inputting the screen size.

When mounting it in the ceiling it needs to be inverted.
https://www.projectorcentral.com/Ben...ulator-pro.htm

Not sure how you're going to mount it on a shelf on a rear wall 5' up. Wouldn't the seating be in front of the projector?


But the larger issue is the HT3550 is too dim to be used with a 120" screen, I assume 1.0 gain (white), for 3D. IMO.
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post #6 of 19 Old 06-28-2020, 11:09 AM - Thread Starter
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Originally Posted by noob00224 View Post
If think you're confused about this projector's specifications.

There's no 0% offset. 100% offset means the center of the lens is at the same height as the bottom of the screen if the projector is on a table, and top of the screen if the projector ceiling mounted.

It only has a very small amount of vertical lens shift, which is noted at the bottom of the calculator page after inputting the screen size.

When mounting it in the ceiling it needs to be inverted.
https://www.projectorcentral.com/Ben...ulator-pro.htm

Not sure how you're going to mount it on a shelf on a rear wall 5' up. Wouldn't the seating be in front of the projector?


But the larger issue is the HT3550 is too dim to be used with a 120" screen, I assume 1.0 gain (white), for 3D. IMO.
I think I understand the lens offset. If I set the projector on a shelf, 5 ft up or so (well above the seated viewing position), the screen would also have to be quite low (or high if pic is inverted), which isn't an option. The only way to get there would be copious amounts of vertical shift, right?

I'm looking at a 1.1 gain screen (white) and was told in a dark room the 3550 was bring enough? I was worried about that too.

This explanation makes sense to me:

Offset is the other key measurement in determining where to place the projector and/or the screen if you are starting from scratch. Offset is the spec that tells the user how much of the projected image is above or below the lens of the projector. A 0% offset would mean the lens would be dead center in the image; not ideal for many ceiling or table mounted locations. Most DLP projectors have an offset of 100% or more meaning that the lens is entirely below/above the projected image.

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post #7 of 19 Old 06-28-2020, 11:28 AM - Thread Starter
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Originally Posted by scoobdude View Post
I was in a similar situation. 13'8" x 20' and wanted to use the shorter side. I was considering the ht3550 as an upgrade to my w1070 but but decided on the epson 3200 since it was also a few bills cheaper than the benq refurb.

While it might be a very tight fit the epson 3200/3800 just might fit in there with a 11'6" minimum distance at that size. Would also give you more flexibility on placement. But... you will lose the dci-p3 color as it does only 78% (113% of 709) of it. But it's 3k lumens so it's a trade off. It's also heavier at 15lbs.

Also the 3550 has a small vertical lens offset from the top of the screen of 10% i believe which should put you at 0%. But there is no horizontal. The epson has +/- 60% vertical and 24% horizontal.



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Thanks. The 3800 was my 2nd choice. I need to plug it into the calculator to see if it shifts enough for my plans. I know the 120" screen in this room is on the large side, but I was in someone else's room and when wearing 3D glasses, the picture filled the entire lens...very immersive.
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post #8 of 19 Old 06-28-2020, 11:42 AM
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Quote:
Originally Posted by chiefp View Post
Thanks. The 3800 was my 2nd choice. I need to plug it into the calculator to see if it shifts enough for my plans. I know the 120" screen in this room is on the large side, but I was in someone else's room and when wearing 3D glasses, the picture filled the entire lens...very immersive.
You can have the projector anywhere from a few inches above to a few inches below the screen if you don't use any horizontal lens shift.

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post #9 of 19 Old 06-28-2020, 01:26 PM
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Quote:
Originally Posted by chiefp View Post
So I ordered a BenQ 3550 yesterday...but failed to consider the lens offset when I picked it. I'm building a small HT room, that has a ceiling fan that the wife says has to stay. I was ok with that and planned to mount projector on a shelf on the rear wall 5 feet up or so. I'm looking to use a 120" screen and the 3550 has a semi short throw so I was good there ( room is 11 x 13).

Everything I've looked at seems to be built for ceiling mounting and has 100% lens offset or more. I need something with 0%. I can't seem to find a way to search anyone's site for compatible options. Suggestions? Looking for 4K, with 3D and less than $2K. thanks.

I'd suggest getting a short throw projector that can be mounted between the fan and screen.

Candidates include the GT1080HDR, GT1090HDR (laser) ( both = 120in at 4ft 5in) ) ZU406ST (laser) = 120in at 4ft 4in). These projectors should do well for 3D and will take a 4K HDR input and downscale it to 1080P HDR.

Additionally, you could replace the ceiling fan with a very low profile ceiling fan:

https://smile.amazon.com/Hunter-5106.../dp/B00DOQJHUG

The above fan requires only 9in of depth from the ceiling, so you could mount the HT3550 on a typical ceiling mount on the opposite wall, and the light beam would clear the ceiling fan with the top edge of the screen at 9in or more from the ceiling. However, even your existing ceiling fan might still allow for a ceiling mounted projector. It would help to have the exact dimensions of the room and fan.

The HT3550 is a bit dim when using the WCG (P3) filter, With the WCG filter off, and using Smarteco, it should do OK on a 120in screen. Assuming you get the fan sorted out then there are alternatives such as the TK850, UHD50, UHD50X, UHD52ALV.
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post #10 of 19 Old 06-28-2020, 02:48 PM - Thread Starter
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Originally Posted by DunMunro View Post
I'd suggest getting a short throw projector that can be mounted between the fan and screen.

Candidates include the GT1080HDR, GT1090HDR (laser) ( both = 120in at 4ft 5in) ) ZU406ST (laser) = 120in at 4ft 4in). These projectors should do well for 3D and will take a 4K HDR input and downscale it to 1080P HDR.

Additionally, you could replace the ceiling fan with a very low profile ceiling fan:

https://smile.amazon.com/Hunter-5106.../dp/B00DOQJHUG

The above fan requires only 9in of depth from the ceiling, so you could mount the HT3550 on a typical ceiling mount on the opposite wall, and the light beam would clear the ceiling fan with the top edge of the screen at 9in or more from the ceiling. However, even your existing ceiling fan might still allow for a ceiling mounted projector. It would help to have the exact dimensions of the room and fan.

The HT3550 is a bit dim when using the WCG (P3) filter, With the WCG filter off, and using Smarteco, it should do OK on a 120in screen. Assuming you get the fan sorted out then there are alternatives such as the TK850, UHD50, UHD50X, UHD52ALV.
Thanks. Your the 2nd person to say the 3550 isn't going to be bright enough. I've been in the room with a tape measure and have decided to make a couple changes to the plan as my wants were getting ahead of my budget.

I'm going to drop to 110" screen for a little more flexibility, will that do much for the brightness issue?

Wife won't let me change the fan, but I'm going to remove the down rod. That will leave about 18 inches to clear (large fan/fancy lights). Walls are 9 foot high. If I ceiling mount the 3550 at 20 inches down, projecting at 11'6", I'll get the 110 screen, with the bottom of the screen about 31 inches up from the floor. That puts the screen bottom about 12" below eye level when seated...if I've done the math right. I'd like it a little higher, so I can put a media shelf (28" tall) in front. I can still do it, but couldn't put anything on top.

But if it's going to be too dark... The PC brightness meter says I need 27 FL for a room with ambient light and BenQ says it has 57 FL in this configuration. And I have light control. Seems like more than enough. What don't I understand? Happy to return this and get something else if I need to.
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post #11 of 19 Old 06-28-2020, 03:28 PM
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Quote:
Originally Posted by chiefp View Post
Thanks. Your the 2nd person to say the 3550 isn't going to be bright enough. I've been in the room with a tape measure and have decided to make a couple changes to the plan as my wants were getting ahead of my budget.

I'm going to drop to 110" screen for a little more flexibility, will that do much for the brightness issue?

Wife won't let me change the fan, but I'm going to remove the down rod. That will leave about 18 inches to clear (large fan/fancy lights). Walls are 9 foot high. If I ceiling mount the 3550 at 20 inches down, projecting at 11'6", I'll get the 110 screen, with the bottom of the screen about 31 inches up from the floor. That puts the screen bottom about 12" below eye level when seated...if I've done the math right. I'd like it a little higher, so I can put a media shelf (28" tall) in front. I can still do it, but couldn't put anything on top.

But if it's going to be too dark... The PC brightness meter says I need 27 FL for a room with ambient light and BenQ says it has 57 FL in this configuration. And I have light control. Seems like more than enough. What don't I understand? Happy to return this and get something else if I need to.
A 120in screen = 42.6 ft2 and a 110in = 36 ft2, so the 120in requires 18% more lumens for same brightness.

The HT3550 measures between ~900 - ~1300 lumens in bright/smarteco (depending on the review) and about 30% less with the WCG filter enabled. A 110in screen should be fine, with lights off viewing even with the WCG engaged, and OK with some light and WCG off. This review measured just under 700fl with the WCG engaged:

https://hometheaterhifi.com/reviews/...jector-review/
which is similar to this:
https://www.passionhomecinema.fr/blo...-second-round/

but here they get ~900 lumens with the wcg engaged:
https://www.projectorreviews.com/ben...formance-page/


A 110in screen is 54in high, add 31in for height off the floor = 85in top of screen height from floor, or 23in from ceiling. So your measurements seem ok and you could probably raise the screen by a few inches.
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post #12 of 19 Old 06-28-2020, 10:31 PM
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Quote:
Originally Posted by chiefp View Post
I'll get the 110 screen, with the bottom of the screen about 31 inches up from the floor. That puts the screen bottom about 12" below eye level when seated...if I've done the math right. I'd like it a little higher, so I can put a media shelf (28" tall) in front. I can still do it, but couldn't put anything on top.
I know this is all personal preference but sounds like your mounting your screen too high. First off putting your Media center (AV components) in the front of the room is very old school way of thinking. Your AV equipment should be in the back of the room close to the projector (hidden in a closet even better) for two reasons, shorter HDMI runs are more reliable/cheaper/safer and no distracting panel lights near your screen. The only thing near your screen should be LRC speakers with inexpensive/easy to hide speaker wire run to the front of the room. Eye level should be 1/3 to 1/2 way up from the bottom of the screen typically.
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post #13 of 19 Old 06-29-2020, 02:39 AM
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Originally Posted by chiefp View Post
I think I understand the lens offset. If I set the projector on a shelf, 5 ft up or so (well above the seated viewing position), the screen would also have to be quite low (or high if pic is inverted), which isn't an option. The only way to get there would be copious amounts of vertical shift, right?

I'm looking at a 1.1 gain screen (white) and was told in a dark room the 3550 was bring enough? I was worried about that too.

This explanation makes sense to me:

Offset is the other key measurement in determining where to place the projector and/or the screen if you are starting from scratch. Offset is the spec that tells the user how much of the projected image is above or below the lens of the projector. A 0% offset would mean the lens would be dead center in the image; not ideal for many ceiling or table mounted locations. Most DLP projectors have an offset of 100% or more meaning that the lens is entirely below/above the projected image.
The PC calculator is with the highest brightness.

As I said in the previous post, the HT3550 is not bright enough for an 120" white screen in 3D. For SDR even HDR it should be fine.
If you want a brighter image for 3D get the TK850 or UHD52ALV, or some of the 1080p laser models mentioned previously.

The HC3800 is 3LCD and it's not as good as DLP when it comes to 3D. The 5050UB has been reported to do ok. You could get this one since it has a lot of lens shift.

0% offset if it would exist would mean the center of the lens would be at the same height as the top of the screen if placed in a regular position (Not reversed), so it doesn't make any sense.

Some projectors with lots of lens shift like the Epsons have their default at the same height as the middle of the screen.
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post #14 of 19 Old 06-30-2020, 09:28 AM - Thread Starter
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I know this is all personal preference but sounds like your mounting your screen too high. First off putting your Media center (AV components) in the front of the room is very old school way of thinking. Your AV equipment should be in the back of the room close to the projector (hidden in a closet even better) for two reasons, shorter HDMI runs are more reliable/cheaper/safer and no distracting panel lights near your screen. The only thing near your screen should be LRC speakers with inexpensive/easy to hide speaker wire run to the front of the room. Eye level should be 1/3 to 1/2 way up from the bottom of the screen typically.
I don't have any other option than to put the equipment under the screen in this room. But I take your point and have already sourced a shorter media center so I can drop the screen further. I've given up on the BenQ 3550 and am now learning to the Epson 3800 and an 110" screen. With all the lens shift it has, I should be able to bring the screen down; albeit still a little higher than preferred.
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post #15 of 19 Old 06-30-2020, 10:11 AM - Thread Starter
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The PC calculator is with the highest brightness.

As I said in the previous post, the HT3550 is not bright enough for an 120" white screen in 3D. For SDR even HDR it should be fine.
If you want a brighter image for 3D get the TK850 or UHD52ALV, or some of the 1080p laser models mentioned previously.

The HC3800 is 3LCD and it's not as good as DLP when it comes to 3D. The 5050UB has been reported to do ok. You could get this one since it has a lot of lens shift.

0% offset if it would exist would mean the center of the lens would be at the same height as the top of the screen if placed in a regular position (Not reversed), so it doesn't make any sense.

Some projectors with lots of lens shift like the Epsons have their default at the same height as the middle of the screen.
The 5050UB is outside the budget. I'm going with the HC3800. I understand the DLP advantage for 3D, but the lens shift ability of the 3800 wins out for my needs. The 3800 is on Projector Central's Top 10 list for 3D, so it shouldn't be that much of a trade off. It's predominantly for 2D movie nights, with an occasional 3D in there.

Thanks for the help!
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The 5050UB is outside the budget. I'm going with the HC3800. I understand the DLP advantage for 3D, but the lens shift ability of the 3800 wins out for my needs. The 3800 is on Projector Central's Top 10 list for 3D, so it shouldn't be that much of a trade off. It's predominantly for 2D movie nights, with an occasional 3D in there.

Thanks for the help!
How about a 5040UB?

Difference between the 5050 and 5040:
https://www.avsforum.com/forum/68-di...l#post59777804

https://www.avsforum.com/forum/199-f...-151-00-a.html
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post #17 of 19 Old 06-30-2020, 11:04 AM - Thread Starter
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That was 1st on my list. Epson had refurbs on sale for $1150...but I missed the boat.
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post #18 of 19 Old 06-30-2020, 11:18 AM
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That was 1st on my list. Epson had refurbs on sale for $1150...but I missed the boat.
They come back in stock from time to time. They get sold out pretty quickly.
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post #19 of 19 Old 06-30-2020, 11:23 AM
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Originally Posted by chiefp View Post
The 5050UB is outside the budget. I'm going with the HC3800. I understand the DLP advantage for 3D, but the lens shift ability of the 3800 wins out for my needs. The 3800 is on Projector Central's Top 10 list for 3D, so it shouldn't be that much of a trade off. It's predominantly for 2D movie nights, with an occasional 3D in there.

Thanks for the help!

See this post before ordering the HC3800:

https://www.avsforum.com/forum/68-di...l#post59879516
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