Owen Radmore Posted May 9, 2018 Share Posted May 9, 2018 Hi We are looking to rear project a backdrop. Projection Distance 0.5mHeight 3.5m Ansi Lummens 6000 Weight projector less than 7kg The size wed be looking at would be approx 3mx3m Thinking possibly two projectors one top do top part/one todo bottom, is there software that will split the output across two projectors automaticaly? What lens would be required? Any other advice Thanks Owen, Link to comment Share on other sites More sharing options...
timsabre Posted May 9, 2018 Share Posted May 9, 2018 I doubt it is possible to get a 3m wide image with a projection distance of 0.5m. That would be a 0.16 lens ratio, even ultra short throw ones are about 0.25 lens, and they max out at about 4000 lumens. Link to comment Share on other sites More sharing options...
ninjadingle Posted May 9, 2018 Share Posted May 9, 2018 Some idea of budget might be helpful? I think your constraints are too tight and something will have to give, so perhaps tell us what isn't so important and what is an absolute must have? Link to comment Share on other sites More sharing options...
Owen Radmore Posted May 9, 2018 Author Share Posted May 9, 2018 I doubt it is possible to get a 3m wide image with a projection distance of 0.5m. That would be a 0.16 lens ratio, even ultra short throw ones are about 0.25 lens, and they max out at about 4000 lumens. What im looking at is to project a backdrop so what is possible with a 0.25 then using two projectorseither one image on top of the other or each image side by side? Some idea of budget might be helpful? I think your constraints are too tight and something will have to give, so perhaps tell us what isn't so important and what is an absolute must have? Im not sure what budget has got to do with it at the momment! Im interested in what is possible ie what is the biggest image I can get side by side or on top of each other. Once I know what I need, what is possible then ill look at what budget is required and then secure it. Link to comment Share on other sites More sharing options...
timsabre Posted May 9, 2018 Share Posted May 9, 2018 Lens ratio is throw dist / image size so a 0.25 lens would give you 2m image from 0.5m throw (that's from the lens so you need extra distance for the body of the projector). The difficulty with ultra short throw is image distortion, they are usually used onto a fixed rigid screen as any slight misalignment makes a big mess of the picture. I'm not sure if you can back project with them and positioning multiple ones to blend would be very hard. Really your projection distance is too small to be practical. Could you front project from a high angle? Link to comment Share on other sites More sharing options...
Joe Fernand Posted May 10, 2018 Share Posted May 10, 2018 3mx3m - have you got your 'shape' correct? Joe Link to comment Share on other sites More sharing options...
GR1 Posted May 10, 2018 Share Posted May 10, 2018 Use a video wall. Link to comment Share on other sites More sharing options...
timsabre Posted May 10, 2018 Share Posted May 10, 2018 Yes that's a good idea if budget is not important. Some led video panels would do it beautifully. Link to comment Share on other sites More sharing options...
Shez Posted May 10, 2018 Share Posted May 10, 2018 Unless there's a good reason for specifically needing projection, I'd agree that video wall would be much more practicable and would likely look much better. (Up until a few months ago I would have expected the cost to be prohibitive in comparison but then I worked on an event with a flexible video wall backdrop, the type of which I'd not seen before, which cost less than even a single high end projector to hire!) Link to comment Share on other sites More sharing options...
kitlane Posted May 10, 2018 Share Posted May 10, 2018 How far away are the audience? That will determine the necessary resolution / pixel pitch if using LED video wall. Link to comment Share on other sites More sharing options...
Owen Radmore Posted May 10, 2018 Author Share Posted May 10, 2018 Lens ratio is throw dist / image size so a 0.25 lens would give you 2m image from 0.5m throw (that's from the lens so you need extra distance for the body of the projector). The difficulty with ultra short throw is image distortion, they are usually used onto a fixed rigid screen as any slight misalignment makes a big mess of the picture. I'm not sure if you can back project with them and positioning multiple ones to blend would be very hard. Really your projection distance is too small to be practical. Could you front project from a high angle? Is that a 2m diagonal image? Why would you not be able to back project? Front projection options would be 10m from Screen at 3.5m height but it would be from one side Unless there's a good reason for specifically needing projection, I'd agree that video wall would be much more practicable and would likely look much better. (Up until a few months ago I would have expected the cost to be prohibitive in comparison but then I worked on an event with a flexible video wall backdrop, the type of which I'd not seen before, which cost less than even a single high end projector to hire!) I had looked at various videowall of the flexible variety eg Eurolite LED Curtain, what do people think of these as an option?what was the make of the videowall on the production that you worked on? I'm potentialy looking to buy. Yes that's a good idea if budget is not important. Some led video panels would do it beautifully. I never said budget was not important just that I wanted to know what was possible. Most led panelswould be too heavy. Link to comment Share on other sites More sharing options...
sunray Posted May 10, 2018 Share Posted May 10, 2018 Oh how times have changed, late 90's we regularly installed mirrors in back projection rooms. One started at a corridor which just accepted a standard 30inch door and frame which made the projection room only 34" (0.86m)deep. A 15x8ft (about 4.6x2.4m) screen replaced one wall and using 4 projectors and 8 mirrors we achieved a bit wider than 16:9 using 2widex2high or more commonly a pair of weird ratio side by side images using 1widex2high. Absolute pig to align and absolutely no movement permitted anywhere. I haven't tried to fold a piece of paper to see if 3x3m is possible with a pair but some of the old techniques do still work. Link to comment Share on other sites More sharing options...
Shez Posted May 10, 2018 Share Posted May 10, 2018 Unless there's a good reason for specifically needing projection, I'd agree that video wall would be much more practicable and would likely look much better. (Up until a few months ago I would have expected the cost to be prohibitive in comparison but then I worked on an event with a flexible video wall backdrop, the type of which I'd not seen before, which cost less than even a single high end projector to hire!) I had looked at various videowall of the flexible variety eg Eurolite LED Curtain, what do people think of these as an option?what was the make of the videowall on the production that you worked on? I'm potentialy looking to buy. That Eurolite has a huge pixel pitch ~50mm so unless you're just showing abstract images or your audience is 50+ meters away, it won't be much good. The stuff I saw was from www.easyflexled.com in Daventry. I didn't catch the brand but they have plenty of options down to about 3mm pitch. Weight is negligible too compared to traditional panels. Link to comment Share on other sites More sharing options...
Owen Radmore Posted May 11, 2018 Author Share Posted May 11, 2018 Thanks all for all your help! I think I can get more projection distance 1 metre height 3.5m So im thinking two projectors projecting two images What size image would I be able to get overall looking at combining the two images and having them seperate from time to time. The videopanel of the flexible kind might be nice but more expensive id imagine Distance to first audience row 5 metres Link to comment Share on other sites More sharing options...
Owen Radmore Posted May 12, 2018 Author Share Posted May 12, 2018 Ive been looking around Ive been looking at the Optoma eh320 ust. If use 16:9 aspect ratio I could achieve a width of 2.36And height of 2.64m using two projectors one image above the other verticaly. What do people think of this projector? Alternatives? Im presumming id need to mount at different heights to get one image on top of another? Link to comment Share on other sites More sharing options...
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