why most people will not use a 150inch screen

Discussion in 'Projectors, Screens & Video Processors' started by jazz21, Aug 25, 2017.

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  1. jazz21

    jazz21
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    Hi Guys,
    im building a new dedicated home theatre and was browsing through the threads and was wondering why majority people with a dedicated home theatre will not go for 150" screen? some will go 120" and some 138" etc. Is it because people are worried about the picture being to dim?

    Im planning to have a 150" 2.35:1 screen by Screen Innovation zero edge slate 1.2. Viewing distance for front row about 15' and second row about 18'. throw distance 17'-18'. Projector will be Sony VPL-VW550ES 1800 lumens claimed. Movies will in 4K and upscaled 4k, except for 3D.

    Will be using low lamp for all views. My question is would it be to dim for a 150" 2.35:1?
     
  2. Abacus

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    Most projectors are rated for a 300” screen on high lamp mode so 150” will be easy even on low lamp mode.

    User’s buy screens to suit their environment and a lot of users just don’t have space for a 150” screen, if you do, go for it.

    Bill
     
  3. jazz21

    jazz21
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    Thats a relief, thank you Bill.
     
  4. KelvinS1965

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    I think it could be toom dim (the reason most don't go that large). Also the lumens outputs aren't usually quoted for an accurate/calibrated mode and you also need to take into account some lamp dimming in the first 100 hours (allow at least 10% IMHO).

    I've gone for a 3 metre wide AT screen and I'm close to the limit of my JVC X500 having to run in high lamp to achieve around 13-14fL which is a typical target. Some over on AVS target much higher fL so that further limits the potential screen size.

    I saw someone on AVS with a Panasonic AE6000/8000 that was running a 180" screen, which must be incredibly dim even using the less accurate settings.

    I'd do some research first before expecting the VW550ES to light up that screen in low lamp. I'd also do some research generally about panel degradation on Sony projectors. ;)
     
  5. jazz21

    jazz21
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    Here is a bit of my research, email Screen Innovation tech person and told me i would get 25-26fL on low lamp base on my specs as mentioned. That should be enough to light up the screen of that size i hope.
    Panel degradation issue also have been doing research on that to. Been reading all the VW550ES owners threads on AVS forum so far no issues on panel degradation. It seems Sony have solve this issue. Now i dont want to argue about panel degradation on this thread.
    At the present moment i have been using the lower model VW320ES at 1300hrs with no panel degradation. Been measuring the lumens every month now so far so good. Black levels are fine but not as good as the JVCs and the VW550ES. No contrast issues too. For the price i have no complains. Im upgrading to the VW550ES mainly because of the lens memory, better contrast and black levels.
     
  6. mbmapit

    mbmapit
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    I think it will be a push to hit 12fL at that size and throw (especially calibrated). Then once you take in to consideration the lamp dimming over time it may start out OK but over time it will get worse and worse. Try using this:

    Projection Calculator Pro - Projector to Screen Distance
     
  7. dhts

    dhts
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    If you've got a 320 why not just zoom to the screen size you're proposing and see if it's bright enough for you. I don't think the 550 is that much brighter that this won't give you a reasonable clue but my quick bit of maths says you won't hit 25fL assuming low lamp and calibrated using a movie like setting. If you find out the different calibrated lumens between the two you could adjust the screen size accordingly for the test.
     
  8. Peter Parker

    Peter Parker
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    To find out what kind of reflectance level you will be getting from a projector, you dived the screen area (in square feet) into the actual lumens the pj is giving, and then multiply by the screen gain.

    If you are zooming to achieve A 150" diagonal 2.35 screen, you have to use the equivalent 16:9 area. That will give you a square foot area of 74.4ft. Divide that into 1800 and you get 24.2fL. Multiply that by the gain of 1.2 and you get 29fL, so double the DCI target of 14fL.

    Calirated lumens are around 1650 according to Cine4home, so then you will get 22.2fL on a unity gain screen, and 26.6 with a screen gain of 1.2.

    That will be in high lamp mode on a new lamp, which will of course dim over time. Not everyone likes to use high lamp due to the noise (if it's in the same room and not in a hush box). If low lamp mode reduces the lumens by 20%, then you end up with around 21.3fL, so still more than enough. Assuming a 10% loss after 100 hours, that will give you 19fL.

    Ideally it should be measured so things can be set accurately for your machine.

    If the 550 has a manual lens iris, you can use that to dim the image down to 14fL (if that is your preference), and then adjust (open) the iris as the lamp ages to keep it there. Ideally you will need a photopic light meter to measure the lux at the screen when it is giving 14fL, and then you can easily adjust the iris to keep it at that value. No calculating etc needed. Or just get your calibration guy to do it for you when he recalibrates at his recommended intervals.

    Gary
     
  9. dhts

    dhts
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    Does OP mean 150" wide or diagonal and isn't there a fair loss when calibrated ? I'd gone with 87sqft and say 1300 lumens.
     
  10. jfinnie

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    How can you be sure? Do you have original and recent native on/off contrast measurements?
    The problem is that as the lamp ages it becomes dimmer (which also lowers the black floor), so you don't necessarily notice the raised black floor from panel degradation until you install a new lamp.
     
  11. Peter Parker

    Peter Parker
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    I assumed a 150" diagonal 2.35 screen, which is 12.5 feet. That gives a width of 11.5 feet, so an 11.5 feet wide (13.2ft/158ins diag), 16:9 screen has an area of 74.4 feet.

    150" wide as you suggest does give 87.9 square feet, but 22.5fL using 1650 lumens and 1.2 gain.

    I used the 1650 calibrated lumens as measured by Cine4home, as they're usually pretty accurate and know what they're doing, but like I said, some real measurements of the OPs machine would of course be better.

    If your numbers are closer to the truth, that gives 14fL x gain = 17.7fl.

    I agree, it's not unusual to see a drop of as much as 40% after calibration on some machines, but as I haven't done much calibration in recent years, I have to go on what I consider to be reliable third party numbers.

    But I think even with the different numbers, the OP should be fine with his screen on a new lamp, and given that a 50% drop in fL looks around 80% as bright (IIRC), it should look fine as the lamp ages down to around 8fL IMHO, assuming a dedicated room.
     
  12. Rawschach

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    Very helpful that Gary - i just bought a 157 inch screen (up from 99) and did not give any consideration to whether the pj will be bright enough

    Your post has put my mind at ease - just need to build the screen and move the projector further back on the ceiling.....
     
  13. jazz21

    jazz21
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    Thanks for the reply Gary, 19fL should be enough in my book. Your measurements are very helpful.
     
  14. jazz21

    jazz21
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    [​IMG]
    Hey Gary,
    Just calculate using projector central and it stated only 13fL. Im confuse....
     
  15. Peter Parker

    Peter Parker
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    I think PJC assume an already dimmed lamp (can't remember the details but I think it's on their site somewhere), so their numbers will lay between a new lamp at a higher number (lets say 19fL) and a 50% dimmed number (say 9.5fL) so that might be why they're showing 13fL.
     
  16. KelvinS1965

    KelvinS1965
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    I can't speak for Sony projectors, but I find PJC fairly close with JVCs. You also have to take into account the amount of zoom used as nearer the telephoto end will tend to give less light output/higher contrast due to the aperture effect on most projector lenses.

    Another slight issue is the quoted screen gain of 1.2; in practice it may well not measure any more than 1.0. There is a review of screen types somewhere on AVS and pretty much all of them measure 0.2 or 0.3 less than the claimed figure. I know my previous Beamax '1.5' gain screen was much closer to 1.0 than I would have liked. I was able to compare it to a 'reference' 1.0 gain sample and there was barely any measured difference.

    Bottom line is that I still think it will be on the dim side once calibrated and to allow for lamp dimming, especially if used in low lamp. This is also why I think that generally you don't tend to see 150" set ups so much even on AVS.

    I have to confess though that before I bought my meters I had been watching a 5fL image thinking it looked OK. I've been setting my light output (via a manual iris on various JVCs over the years) to a measured 13fL, so I now notice if I revert to 5fL. So maybe just try your existing model zoomed to that size to see if you find it bright enough.
     
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  17. jazz21

    jazz21
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    I agree with your comments on the screen gain. Infact i forgot to mention that is a micro perf AT screen so 1.2 would end up 1.0 gain. I will take your advice and test it on the present PJ first and see. If its too dark then i might have to stretch my budget and get the JVC Z1, that is if i have to jump of the bridge. Thank you Kelvin.
     
  18. jazz21

    jazz21
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    Thank you guys for being supportive.
     
  19. geogan

    geogan
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    I have a post here showing the various light levels measured on my (nearly 150") screen between a brand new zero hours bulb and another bulb with over 3300 hours on it. There is a big light drop off on the old bulb.

    Sony VPL-HW40ES Owners Thread
     
  20. dfdd

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    Bigger is better most definitely. Ever see small cinema screens? No? There big for a reason- the bigger size adds exponentially to the experience
    It's good to do calcs and better if you can mock up prior to purchase- as a previous poster suggested zoom it out to your desired side will give a rough idea of brightness etc.
    I use a Appx 188" 2:35 screen- absolutely fantastic- one of the best upgrades I have made.

    Nb remember your centre speaker needs to be taken into account with the drop of the screen
     
  21. jazz21

    jazz21
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    thank you for light measurements. that makes perfect sense. maybe i will change the bulb every 2500hrs.
     
  22. jazz21

    jazz21
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    If u dont mind me asking what PJ are u using?
     
  23. dfdd

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    JVC X7000, appx 1800 lm, it is great and i use low lamp. I did use an X35 prior to this and also found that fine, the X7000 is brighter, but I would squint with full white screen on both-so bright enough for me. 1.0 gain screen as well. cheers and remember too work out the drop in relation to your centre speaker position
     
  24. AidenL

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    That size is too hard to light up,properly, especially if you want HDR pop.
     
  25. jazz21

    jazz21
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    Hey dfdd,
    what do you mean 'too work out the drop in relation to your centre speaker position'?
     
  26. dfdd

    dfdd
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    when using larger screen sizes, the vertical height of the screen can be significant when fully lowered, resulting in your centre speaker blocking the image.
    not a problem if using an acoustically transparent screen as you can place the centre speaker behind the screen
     
  27. jazz21

    jazz21
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    will be using acoustically transparent screen.
    Thank you dfdd
     
  28. swiftpete

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    I ran a 150 inch screen for last 2 yrs or so with hw40es. No problem with brightness.
     
  29. slave1

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    I'd love to know where ye guys are sourcing your 150" electric screens, I'm upgrading from my 120" and finding them very difficult to track down .... ... .. .
     
  30. dfdd

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    React, draper, Ricky at kalibrate, Allen at ideal av, etc do a Google- loads of options!
     

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