johnb Posted October 4, 2009 Share Posted October 4, 2009 Hi I'm currently looking at better options for a projector for our church than our current arrangements. Looking at the building there is an obvious white wall to project onto either side at the front, however there is not anywhere obvious to actually put the projector. What I'm looking for a is a projector that we can mount on the side wall and then project onto the end wall. There is an obvious project mounting point by the pillar about 3.5m back from the projection wall, and the actual "screen" would be just over 2m in width. Looking around the internet it appears that the projectors for the home market can do this via lens shift, however I can't seem to find any more serious projectors with this feature. The current projector is 300 lumen, and from experience of that anything new would need to be either the same or brighter. At this point in time I'm looking to see if what I want to do is possible at a sensible price. This particularly bearing in mind that if we went down this route we would need a pair of projectors. If anyone can give me some pointers in how best to achieve this, and any ideas of pricing it would be useful. I've attached a diagram below of what I mean in case my description isn't clear enough. CheersJohn http://img384.imageshack.us/img384/1308/cmcprojector.gif Link to comment Share on other sites More sharing options...
Johnparrack Posted October 4, 2009 Share Posted October 4, 2009 For a start point you will need to look at projectors with 1.5 -2.2 lens, because for an xga proj you are at about 1.6x throw (most standard lenses in cheaper projs are 1.7 - 2.2..so you would get a smaller image than your diagram) As for lens shifts, I know the Panasonics have a East-west shift (via a knob on the front of the projector) but I'm not sure that you will get enough shift with the projector that far off centre. I'm sure you can find some specs on the manufacturers sites of any projector that you are currently considering which may help you answer that one more than I can. Would it not be possible to Out rig the projector..eg wall mount + Pole + Hanging Bracket + diagonal Support bracket/arm/scaff? I imagine your current projector is more than 300 lumen (guessing a typo and its 3K lumens)...For that kind of brightness look at the panasonics or Sanyo's (sometimes christie badged)..Both also have a range of lenses which should suit. hope this helps a little..sorry I can't quote model numbers etc, as I'm only a technician and don't know what current models are around in the consumer bracket.... Link to comment Share on other sites More sharing options...
Pete McCrea Posted October 4, 2009 Share Posted October 4, 2009 From memory the Sanyo XT range and above have horizontal and vertical keystone, as well as horizontal and vertical lens shift. They are also quite light (I guess when compared to our bigger units...), so could possibly be mounted on a Unicol stand-off bracket or Gyrolok bracket to help bring the unit closer to the centre line of the screen. A sanyo PLC-XT21 Lists at £2649 ex VAT with the standard lens. Myself and many others would be more than happy to discuss pricing on multiple units. There are also other units that would have similar features and have a lower price point. Would it be possible to drop a column down from the ceiling to the centre line of the screen? Again Unicol (Other mounting hardware manufacturers are available) will do columns for their systems in some long lengths. Or alternatively, is there a wall at the back of the building that the projector could be mounted on? Combined with a long throw lens, this has worked in a few settings we've looked at for churches. Link to comment Share on other sites More sharing options...
timsabre Posted October 4, 2009 Share Posted October 4, 2009 We have almost exactly this situation at our church, with even more of a side offset as there's a big arch in the way. The keystoning required is more than the projector can produce. The projector is always used with a PC and we use a software utility called "NVKeystone" which I downloaded (free) from Nvidia. This allows you to drag the corners of the screen output to "square up" a picture. Works great for us for any type of output (even DVD playback etc), the only snag is you have to manually enable it every time you boot the PC. And you need an nvidia graphics card - the PC we use has this as a 2nd monitor so the actual PC monitor is a "normal" shape. Obviously this is only any good if all your source comes from a fixed PC, anything else you plug in will not be keystoned (different laptops, DVD players etc). Link to comment Share on other sites More sharing options...
sleepytom Posted October 4, 2009 Share Posted October 4, 2009 NEC Projectors with the 3d reform function are the best low budget solution for situations which require serious amounts of keystone. The Barco RLM R6 has 50% horizontal lens shift - I've used them to do off axis projection on a few occasions and as ever with barco they are easy to setup and reliable - but quite pricey too! Link to comment Share on other sites More sharing options...
revbobuk Posted October 5, 2009 Share Posted October 5, 2009 Don't forget to allow for the keystoning when you calculate image size - large amounts of keystoning reduce the size of the final rectangular image. And you'll get some light spill into the area outside the screen - you may want to make a mask to deal with that. Link to comment Share on other sites More sharing options...
mac.calder Posted October 5, 2009 Share Posted October 5, 2009 At most, your horizontal lense shift will be 50%, which means that from a straight and true projection, you can shift the image so that one edge of the image starts from the center of the origional image. 50% shift is a feature generally only found in quite expensive projectors though. If your image is to scale, it may just work. Expect a hefty projector price though. Boardroom/smaller projectors using sideshot (aka horizontal keystone) would struggle to create anything usable with that level of keystone, and it certainly would not look pretty. A point to note is that in a projector with a resolution of 1024x768, horizontal keystone reduces your verticle resolution - so the more you increase the keystone, the less verticle resolution you will have on one edge of the image. I would look at alternative mounting arrangement - ie roof mounts etc. Link to comment Share on other sites More sharing options...
revbobuk Posted October 5, 2009 Share Posted October 5, 2009 You say there's nowhere obvious to put a projector - and folk have suggested looking at outrigger arms, long throw thenses (thenses? lenses!) or ceiling poles. A fourth option available these days is the ultra-short throw projector, which doesn't need to be very far from the screen at all. What you really need is someone to come and take a look / do a site survey. There may be more options than you think! Link to comment Share on other sites More sharing options...
Nick Mawer Posted October 5, 2009 Share Posted October 5, 2009 One possible solution would be to choose the projector of your choice, and use an external scaler like the Kramer VP-728 to handle the geometry. The geometry control in the VP-728 which uses Silicon Optix HQV technology is much better than in most projectors (except the other ones that use HQV!) http://www.hqv.com/index.cfm?page=products.projectors This won't deal with issues that you might have with focusing. Link to comment Share on other sites More sharing options...
revbobuk Posted October 5, 2009 Share Posted October 5, 2009 One possible solution would be to choose the projector of your choice, and use an external scaler like the Kramer VP-728 to handle the geometry. The geometry control in the VP-728 which uses Silicon Optix HQV technology is much better than in most projectors (except the other ones that use HQV!) http://www.hqv.com/index.cfm?page=products.projectors Of course, even this solution will lose vertical resolution - if the image fits the nearer edge of the screen, then the pixels in the projector will be optically mapped to a location off screen on the farther edge. And if the projected image is twice the size on the right, then software keystoning can't do anything about the missing 50% of the pixels! Link to comment Share on other sites More sharing options...
David Lee Posted October 5, 2009 Share Posted October 5, 2009 As others have said, you really need to think about getting your projector in the right place. Link to comment Share on other sites More sharing options...
timsabre Posted October 5, 2009 Share Posted October 5, 2009 As others have said, you really need to think about getting your projector in the right place. Unfortunately in many churches, other considerations usually override getting the best projection angle... in which case some sort of keystoning either within or external to the projector is the only way forward. Link to comment Share on other sites More sharing options...
Pete McCrea Posted October 5, 2009 Share Posted October 5, 2009 I would suggest it's more where peoples priorities lie. If they want a good visuals system in keeping with what secular buildings can implement, then they will overcome issues such as sight lines and mounting positions, either through appropriate technology impementation or readjusting their system. If they simply want to be seen to be 'Keeping up with the Jones' then they will do all they can to ensure that the screen doesn't get in the way of the plaque that great aunt Mable left in 1304 and ask for the moon on a stick for £300. We work in a large number of churches, and there are many times when I will ask the church to honestly ask them selves what they will use the kit for, and why they want to spend sensible amounts of money on systems that are likely to go largely unused, often due to ageing congregations. Simply installing a projector won't stop the congregation ageing and draw young people in. That is a complete overhaul of the churches emphasis required to do that. Yes there are times when keystoning the crap out of an image will be considered ok, however I would only look at it as a last resort for the reasons mentioned above and after visiting the options such as alternative mounting positions and different technologies. I would be interested to see if the OP really does have no alternative mounting positions, or whether it is budgetary constraints that are leading to the desired mounting position, or simply not having the awareness of products that those full time in the industry have that may help solve the problem, which isn't meant as a dig at the OP either. Link to comment Share on other sites More sharing options...
sleepytom Posted October 6, 2009 Share Posted October 6, 2009 Conversely... Keystoning the crap out of something with a decent technology (NEC 3d reform does a pretty amazing job compared to the other low end keystone solutions) will result in a perfectly acceptable image (given that what is being projected is some text over a suitably emotive background (ohh clouds now I'm convinced there is a god)) Yes it makes more sense to install a bit of decent rigging to get the projector to the correct position, but really I don't get churches which have spent tens or even hundreds of thousands of pounds on AV kit. They would be better off giving the money to the poor or something, I'm sure god is supposed to care about the poor more than about some potential aliasing artefacts on the hymn words projection! I rarely work in churches, but I've done it enough to know that the core problem with video installs is much the same as in night clubs in that so called "professionals" will quote £90,000+ for a fully digital HD install, the priest / owner will faint and then a volunteer / bouncer will claim to be able to do it all for £1000 (because he has a projector at home that was only £400). So I guess this is a plea for the middle ground! Work out your available budget, and then spend it sensibly. Spend more than you might expect on rigging to get the projector and screen in the correct place and you'll get a much better image than if you blow the budget on an expensive projector and then have to mount it on top of an old pile of books because you don't have the cash for a wall mount! Link to comment Share on other sites More sharing options...
johnb Posted October 6, 2009 Author Share Posted October 6, 2009 Thank you everyone for your replies - I meant to reply last night, however a little thing called work got in the way. Picking up a few points from some of the posts.... - firstly I meant 3000 lumens for the current projector. - unfortunately the ceiling in the church is probably a good 5m or more above the top of where I would see the screen going. - mounting from the back with a long throw lens is a possibility. The throw would probably be in the region of 15m which is not impossible, however the thoughts of two screens - one each side will make this expensive. - the ideas of keystoning outside the projector are interesting, but as with the above point I was thinking about a projector either side and therefore they would need to be keystoned opposite ways. Also I was half thinking about a foldback monitor each side under the projectors, and so would require thinking about where to keystone in the chain. That said I will remember the Nvidia software as it might come in useful in future. - the point from John Parrack on the Panasonic projectors having lens shift is useful. I've been looking at their projectors tonight and looks like I could at least get half way to the wall, which would probably only mean an arm of about 60cm. I'm struggling with the data sheets and manuals that seem to treat horizontal keystone and lens shift as features to include or drop at will. Once place will say a projector can do something, but you go and double check and the manual doesn't mention it! - looking at the lens shift projectors, some seem to quote the off-axis capability as a percentage of the picture, while others as a ratio (eg 6:1) but don't say what the ratio is of. - finally (for these points anyway), picking up on Tom and Pete's points - what I'm currently trying to work out is if the idea is possible, and how much would it cost. This will then allow me to consider if it is worth trying to take forward, or if I need to settle for the current arrangement. Unfortunately I don't have a good photo of the space in question, however this one off the off the website shows the space quite well. Apologies for the poor quality! http://freespace.virgin.net/chessington.methodist/images/061210%20Service%20having%20Church%20Parade%20008%20brightened%20and%20cropped.jpg The photo show the current arrangement of the projector from a floor stand onto the central screen that can raise and lower. What I was looking at was using the while spaces either side above the doors to project onto. As I've said, projecting from the back would probably be possible, however the cost of that throw would probably mean going for a single projector onto the central screen still. I was hoping that using two smaller (hopefully more standard) projectors would bring the costs down. As you can see we do have fun with daylight in the space. We now have blinds fitted to the worst windows which helps, and using the current projector has been useful in getting a feel of what brightness we need. Once again, thank you all for your suggestions, and would welcome any more thoughts people have. CheersJohn Link to comment Share on other sites More sharing options...
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