Projecting Images onto Cyclorama

I am trying to get some ideas on how I might project images (in lieu of changing backdrops as we have no fly tower) onto a cyclorama for a ballet school concert. The obstacles are - that there is no space behind the cyc to rear project (only 10cm) and I suspect that running a high powered projector from the dress circle bar will mean the girls are dancing through the projected images. Any ideas? Cheers.

I don't think Data Projection is going to work well for you. You're right about Projection from the front, It will project onto the performers and cast shadows onto the Cyc (which could look effective!?) If you have sets on stage, you could project onto the top half of the cyc only? In regards to Rear Projection, because the Cyc would be fairly big, you need to have a fair distance between the data projector and the cyc to be able to project over the distance of it. Some Data Projectors allow you to fit a short throw lens to them, but you would still require quite a few metres distance between the projector and the Cyc (and even then, depending on the thickness of your Cyc, a rear projected image may not be that clear). If it is moving images that you are looking for then I do have a suggestion (however is not a cheap one). LED walls allow you to display images on them from Data or Video. Do a google search of them and you will see what I mean. Contact an AV company in your city and they will be able to provide you with dimensions and hire cost. These are used in a lot of live concerts and add a very bright and effective visual to the stage. It would definately add a modern edge and a different dimension to a ballet concert! Good Luck!

Most modern projectors have keyhole(?) correction, which allows you to project from an angle. This allows you to set the projector above the stage, and shoot downwards onto the cyc. However, I don't think you can get enough adjustment to get the projector close enough to avoid shadows. So that's really no help at all. You might hire some of those new-fangled pattern projecting lamps. :) www.meltheco.org.au

Have you thought of gobos? Not sure of your budget, facilities or how many 'scenes' you want to create, but this could be an option. For instance, if you want a starry night sky, a city scape and jungle - these are all achievable. Get some wide angle profiles, most gobo manufacturers have a great range of stars, windows, buildings and leaf break ups. You could layer these on top of a coloured cyc aswell. Much cheaper than LED screens, much less hassle than a projector (depending on your skills and ability to cue up a projector from a lighting console). Hope it goes well.

There is a new product on the market called "Pandoras box" and it allows you to project on the cyc from steep side angles with a projector each side, it corrects for the distortion like an elaborate keystone adjuster and overlays the two images. This is not a panacea for the situation as you need very powerful projectors to give a reasonable intensity over a huge area like a cyc and you still have to leave a clear distance in front of the cyc to stop shadows. I will be trialling one of these shortly to see how practical it is.It is not cheap, neither are high power projectors.

Have you tried: www.theatrequip.com.au/cycs.htm For an excellent article on the use of projection cycs, see: http://www.gi-info.com/projection_cyclorama_procyc.html Cheers,

The requirement was 10cm behind the cyc not 10 feet.

I am going to try out one of these new ultra short throw image projectors used today for white board work. I saw one the other day and the ultra wide and from a ceiling mounted projector only feet away covered a pretty wide are without distortion. The beauty of these projectors is; i) short throw minimum light loss due to square law ii) no interference from cast shadows – projector mounted on lighting bar in front of cyc ii) wide angle achieved These are available from Hitachi for one.......... Cheers - Peter (Brisbane) Anyone tried one……….??

Sorry to contradict but a short throw does practically no effect on the intensity, the intensity on the screen will be the output lumens - the efficiency of the lens system divided by the area of the screen, so a 1000 lumen projector with a long throw lens will give you exactly the same intensity as the same projector with a short throw lens given that they are each filling the same size screen and the lenses have the same efficiency, light loss in air is extremely small.

Can you explain how that works David? Light intensity is calculated using the inverse square rule, or if you like, when the distance between source and measurement point doubles, the intensity of the light has diminished by a factor of 4 (two squared). www.meltheco.org.au

The intensity reduces by a factor of four simply because the available light is now spread over 4 times the area, of course the law only applies to a fixed angle, a zoom lens changes the equation.