The above Ad will no longer appear after you Sign Up for Free!

Projectors...

Discussion in 'Lighting and Electrics' started by Charc, May 9, 2007.

  1. Charc

    Charc Well-Known Member

    Messages:
    1,850
    Likes Received:
    46
    Okay this is loosely related to lighting, but it does have to do with light. I am talking about a projector for my theater. Who here is honestly surprised that the school cut it out of the renovation budget, only to 3 years later realize they need one? Well the head of school has finally given the go-ahead for us to get a mounted projector. I'm praying they wont' half ass this too but not running the cable, or not running the cable to the stage, so we can't use it with powerpoints. Unfortunately this is running through the Technology Dept., not Theatre Dept, so I have to work closely with the computer teacher on this one. He encouraged me today to write a note to the head of school outlining what we need. As I have no real knowledge about projectors, and mounting them, I hoped some of you could shed some light on this situation. I don't want the administration to mess something else up, so I wanna make sure we get the right projector in the right place.

    My questions include:
    -What is the appropriate number of lumens? I think we are looking at 75ish foot throw.
    -What is the significance of contrast ratio, and what should I look for? I'm afraid it would get washed out during the day, as the company who installed our curtains messed up, and light pours through the windows.
    -Is resolution going to be a factor at this distance?
    -What types of features are on various projectors, what should I look for? What differs on a projector the designers assume will be deadhung for presenting applications?
    -What type of airflow do these need, if any?
    -Will long runs of video cable degrade in signal quality?
    -What is the best place to hang? Up on the ceiling keystoned to high hell, straight on from a back of house pipe?
    -Where are these commercially available?
    -What is the ballpark price?
    -What is the lamp life in hours going to be around?

    Thanks guys (and gals), I had a hard time finding this detailed information on my own.
     
    Last edited: May 13, 2007
  2. DarSax

    DarSax Active Member

    Messages:
    606
    Likes Received:
    9
    Location:
    Bethesda MD
    75 feet? That is one hell of a throw. I know you can get an image out of a 2,000 lumen projector from that distance, but it's very dim.
     
  3. Charc

    Charc Well-Known Member

    Messages:
    1,850
    Likes Received:
    46
    Ya know, I am not very good with estimates. It's possibly i am up to 30 feet over the mark. :cry:

    Edit:
    I was thinking of mounting the projector in either of these red circles:
    [​IMG]
     
    Last edited: May 9, 2007
  4. gafftaper

    gafftaper Senior Team Senior Team Fight Leukemia

    Messages:
    12,470
    Likes Received:
    2,456
    Occupation:
    Theater Manager & T.D.
    Location:
    Seattle, Washington
    What are the dimensions of your screen?
     
  5. Charc

    Charc Well-Known Member

    Messages:
    1,850
    Likes Received:
    46
    Oh man, oh man! Busting out the questions I have no answer to! I'm under-prepared today guys. It is exactly the width of the proscenium, and the height of the catwalks to the stage. It fills in that entire space. I think that translated into 30 feet wide, and around 30 feet tall (if not taller).

    Edit:
    Edited photo with about the area of the screen added in.
     
    Last edited: May 9, 2007
  6. drawstuf99

    drawstuf99 Active Member

    Messages:
    152
    Likes Received:
    3
    Without knowing too much a/b your space I'd suggest mounting it on the ceiling where one of your circles is simply because it's closer.

    We've got a projector mounted in a similar way at our school at a/b a 30 foot distance and it works quite well; however, I dont have any idea as to what type of projector it is.
     
  7. stantonsound

    stantonsound Active Member

    Messages:
    360
    Likes Received:
    15
    Location:
    Charlotte
    I would recommend getting the brightest projector available. It looks like you are able to access that area from a catwalk (maybe?). I am sure that your school has a few projectors. Take one up there and try it. If it is a 2,000 lumes or cheaper, you will probably not be able to see the image very clearly. This will demonstrate to your teachers that you really need a bright projector. It appears as if the screen is approximately square and is at least 25' by 25'. I would say to try and get a 5,000 or so lumen projector. Anything less will look cheap and dim.

    The lamp life really depends on the type of lamp you buy and the usage.

    Take a look at projectorcentral.com. It is a great website. It has interactive graphs that show you how bright it is going to be at different distances and screen sizes. Take a look at the 3M x90w projector.


    ps. "gonna" is not a word!
     
  8. JSFox

    JSFox Active Member

    Messages:
    141
    Likes Received:
    4
    Location:
    The Tundra
    I would strongly suggest talking to a local AV house and get recommendations from 1, 2, or 3 of them.

    Besides the size you also need to know the gain of your screen, screen color, as well as the type of refraction (eg, is is glass bead, matt, etc.) as these will have a huge impact on what kind of image you get from different projectors.

    If you have alot of ambient light from poor shading of windows you may need to consider rear projection instead of front as no projector can cut through alot of ambient with inexpensive screen material (or even the most expensive).

    What are all of your uses? Do you need a projector with good black levels or is dark grey good enough?

    What resolution do you need and what types of inputs and how many of each? Do you need a seperate switcher?

    How critical is up-time? EG, do you need a dual lamp system so that you won't loose image during a presentation?

    You may want to consider a smaller screen. I have a 62' throw to an 18' x 18' screen with a Sanyo XF41 projector and it cannot deal with much ambient light. And, while this screen works well for watching movies it is extremely big and distracting for most other uses (this is a 740 seat theatre with a 42' proscenieum). Many times we'll only use the upper 2/3's or upper half of the projection image area and only lower the screen enough for that portion. We have 2 16' wide x 9' high rear projection screens on a downstage flyline that we do rear projection to using fairly inexpensive projectors and this is often the preferred option.

    Good luck,
     
  9. Charc

    Charc Well-Known Member

    Messages:
    1,850
    Likes Received:
    46
    Thanks for that advice, I am going to check out projectorcentral.com right now.

    P.S.
    Offending "not words" have been edited. Though, I do have to say a word in my defense, my spell checker doesn't flag it, and American HeritageĀ® Dictionary of the English Language, Fourth Edition
    Copyright Ā© 2006 by Houghton Mifflin Company includes "gonna".
     
  10. SHARYNF

    SHARYNF Well-Known Member

    Messages:
    1,911
    Likes Received:
    157
    Don't worry about the word police ;-) http://www-personal.umich.edu/~jlawler/aue/gonna.html


    Couple of things, projectors typically can work in different sizes, typical standard tv is 4:3 format, widescreen tv is 16:9 in pc/vga mode you can typically get a square format.

    In general you want to have the projector as close to the screen as you can get it and still project the size of the image you want, as the fall off in lumens over distance is a factor. You are looking at a pretty big screen, typically the size of a small movie theater, but much higher. Depending on what you want to project if it is video you are not going to use the height you have.

    If the room is totally dark, I would say from experience with a Sharp Notevision 2000 lumen projector you CAN get a workable image, but you will see a degradation in the intensity of the colors. A lot also depends on the technology of the projector, DLP tends to look brighter. The problem is the lumens ratings of the projectors are really all over the lot.

    In the same movie theater I also used a JVC DLA RS1 which is rated for 600 lumens and the image looked better. Part of the issue is the format of the image, how the up converting is done etc. and that the native resolution was 1920x1080 but has a very high contrast ration of 15,000 to 1 which dramatically improves the image

    http://pro.jvc.com/pro/pr/2006/releases/dlars1_release.html

    Going forward, the wide screen format is the future, and HI Def is also here to stay, so if you are purchasing a unit, I would look to the newer units.

    Also keep in mind that the gain of the screen is a factor, but higher gain reduces the viewing angle, but in your situation based on the size of the screen it may not be a factor

    In the older days, people would use a Christie for this size of screen
    http://www.christiedigital.com/christie/tools/projectorcomparisonchart.aspx?region=AMEN

    Sharyn
     
  11. JSFox

    JSFox Active Member

    Messages:
    141
    Likes Received:
    4
    Location:
    The Tundra
    I'm not sure you'd be able to see much of an image with 2000lm @ 30x. I'm throwing 7700lm @ 18x and it doesn't take much ambient to start washing things out.
     
  12. SHARYNF

    SHARYNF Well-Known Member

    Messages:
    1,911
    Likes Received:
    157
    Ambient light and contrast of course is the major factor in the analysis. I agree if you have any ambient light you are looking at needing much higher lumens. Really depends on what you are going to try to accomplish. If you have a higher level of ambient light, even 10,000 lumens will be inadequate

    Sharyn
     
  13. Edrick

    Edrick Well-Known Member Premium Member

    Messages:
    1,314
    Likes Received:
    35
    Location:
    Boston, MA
    We just forked out 14 + Grand for our projector, but it has yet to be installed yet. It's being mounted where our booth is and has to throw down to the stage across 740 seats. Which is about 100 feet.
     
  14. SHARYNF

    SHARYNF Well-Known Member

    Messages:
    1,911
    Likes Received:
    157
    This is typical where the people doing the install/ design as they would with a film projector. Main reason was that a film projector has more difficulty projecting an image when the plane of the gate is not paralle with the plane of the screen, So you don't have the option with film to have the projector over head projecting down to the screen. this is NOT the case with a video projector, and as such IMO putting it that far back from the screen in not a good idea.

    Sharyn
     
  15. Charc

    Charc Well-Known Member

    Messages:
    1,850
    Likes Received:
    46
    So let me see if I got this straight so when we move forward with this I'll know what I'm talking about.

    It's gonna better to mount this up on the ceiling (red circle, page 1) and keystone it, than it would be to mount it all the way in the back of the house? This is because video projectors are fine with projecting from above, so our main concern should be how close we are?
     
  16. SHARYNF

    SHARYNF Well-Known Member

    Messages:
    1,911
    Likes Received:
    157
    You will need a lens distance combination that will get the size image you want, in some cases you can wind up at a long distance because the projector is not capable of generating the size image you want, BUT if you look at the projector specs usually they will tell you the distance range, and max image size. But yes in general the closer you are the the screen, creating the image size you need, the better. Usually the close to the screen is limited by the lens, and the far is limited by the brightness. The issue you may have is that you are looking for a very large image, and you are going to need a lens system that will let you get that size at the distance from the screen you are looking at. There are converter lens, but they are expensive and adding the additional lens causes loss and image distortion.
    So in a long round about way, once you have determined the size that you must have, then you need to find a projector/lens combo that will give you this image, and typically you are better off if you place the projector as close to the screen as you can.

    A couple of points, remember if you have the projector in a remote location, you are going to need to be able to control it, so you need probably some sort of wired remote, IR remotes can work, or ir/radio remotes. In addition if you are using this in a theatrical setting, you are going to want to look at some sort of shutter, so that you can block the image, since blacking the image or turning off the projector is typically not practical
    Sharyn
     
    Last edited: May 19, 2007
  17. fredthe

    fredthe Active Member

    Messages:
    442
    Likes Received:
    55
    Location:
    Maryland
    IMHO, You'd be better mounting at the back. Although small projectors have large keystone asjustments, for a screen that size you will probably need a 10-12k lumen projector, and the ones I've seen don't have large keystone adjustments.

    Where a digital projector can componsate for keystone, it can't compenssate for the differing distances to top vs. bottom of the screen. If you are too far off-axis, you will have a noticible drop in image brightness from the top to the bottom of the screen.

    As for bulb life, I figures the run-time cost of the 12k lumen projector in the HS where I volunteer to be about $2.00 per hour.... 1000 hour bulbs, but there are 4 of them, at around $500 each. I'll post the info on screen size and throw when I next look at the drawings; but with all 4 bulbs running, the image is quite acceptable with the houselights up full.

    -Fred
     
  18. SHARYNF

    SHARYNF Well-Known Member

    Messages:
    1,911
    Likes Received:
    157
    Obviously you are going to get different opinions, so here is some more things to think about

    Lets say you get a Christie Roadster HD12k , 12 thousand lumens, this series is very common in productions. You have control over the image since the lens can be tilted (Key stone is to make exactly the type of correction your are looking for, you have physical means in the unit to off set the image and correct for key stone.

    In addition if you look for instance at the Christie lens calculator, you will see that from a throw distance of 20.5 feet you can get an 16:9 image with a width of 28.6 feet a height of 16.1 and a diagonal of 32.8 with a fixed lens of .67:1 HD

    http://www.christiedigital.com/christie/tools/ChristieLensCalculator.aspx?region=AMEN

    You have lots of lens options

    A lot also depends on how you are going to use the screen and projector. In a movie theater setting, you have a screen and an audience but no real stage or objects and people on the stage, so projection straight on is not a problem since you simply need to get the light path about the audience. BUT if you want to use the screen as a back drop or have anything on the stage, then having a higher angle from above can allow you to project the image on the screen behind the items/people on stage. So if you go back to the original image, you will either need to raise the image which is an option considering the 25 foot high screen, so you could move it up 10 feet, or if you want it lower, you will not be able to have people on stage.

    You also might want to be able to fly drapes infront of the screen so that you can trim it up, since it is rare that you will use the square format


    Sharyn
     
    Last edited: May 19, 2007
  19. Radman

    Radman Well-Known Member

    Messages:
    1,219
    Likes Received:
    7
    Location:
    Franklin, TN
    First suggestion is to cut the bottom off the screen. This is for a few reasons:

    (1) You won't be projecting square content. More than likely it will be 4:3 or 16:9 aspect ratios. I recently worked on a show that had tons of projection (11? projectors total) and there were 2 screens about that wide, and I wouldn't be surprised if the trow was about that far. They were 16:9, fed by component video, and that's about all I know. I think they were Sanyo projectors. I might have the information somewhere, I'll look.

    (2) Since you're doing front projection, the projection will intersect anything on stage and you'll have ugly shadows on your screen if the bottom is near the floor. By cutting out the bottom, you are not only meeting a standard aspect ratio, you are also getting the projection above the talent.


    I also second the recommendation to put the projector on the balcony. This reduces keystoning issues, as well as balancing brightness top to bottom. Thirdly, it makes access to the projector much simpler. You can diagnose errors, change lamps, adjust focus, all without requiring a lift.
     
  20. SHARYNF

    SHARYNF Well-Known Member

    Messages:
    1,911
    Likes Received:
    157
    Couple of things to keep in mind
    If you decide to use images from a PC for instance, then the projected image will infact be square.

    If you want to use the projector to create a back drop image and use is as part of the scenery, then the balcony position will not work.

    As I have said, if you just want to use the projector to display video's for an audience or images about any one on stage, then you can use the balcony.

    I've done a lot of these, and again just my opinion, but if you are going to spend the funds for a high end projector, and your are putting it in a performance space, then for most versatility you are not going to want to put it on the balcony.

    Being able to use video projection as a theatrical back drop give you enormous flexibility, and IMO going forward this type of production design is going to become more and more common.

    If you get a projector with the lens setup for large image, short throw, then you can also move the projector for rear projection if at some point you decide to use this for productions.

    On high end projectors, keystone correction is not a major issue.

    It really depends is it for night at the movies, or for theatrical production?
    Keep in mind if for instance you decide to move the image up the screen in order to avoid interference from stage, you need to make sure that people in the seats in the front section can still watch the screen. If for instance your stage is 48 inches from the floor, and then you raise the bottom of the image say 8 feed from the stage, you are then looking at the bottom of the image being 12 feet from the audience floor, and the top of the image being 28 feet from the audience floor, with a mid screen position 20 feet so you need to check you sight lines to make sure this will work.



    Sharyn
     
    Last edited: May 21, 2007

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice