How to cope with non-optimum screen to projector distances?

You are stuck in a venue that doesn’t let you put the screen where you want to, or the projector where you want to, or both!! What to do? Here’s some ideas…

All video projectors have a minimum and maximum distance at which they can fill a certain size of screen. If you go outwith these distances you will either overscan the screen and project onto the surrounding wall etc. or you won’t fill the whole screen. Both look pretty bad, but often the projector position is chosen for you, for example if you have to project from the front of a balcony, or have to avoid a pillar, or don’t have enough room behind the stage etc.

Of course if you are a pro video team you will have an array of wide and telephoto lenses at your disposal, but back in VLOB-land, this just isn’t an option. Most extra lenses or adapters for projectors cost as much as a small projector itself.

So, how to cope with non-optimum screen to projector distances? I have arranged these tips by the nature of the problem…

If the projector is forced too far from the screen:

 In general this is the easier option to deal with:

  • Remember that you can go up or down to get less distance from the screen. Sometimes placing the projector on the floor will give you less distance, while not obscuring sightlines. You can use keystone correction to correct for the skewing effect.
  • Allow the projector to overscan the screen and put black border on graphics or text. This only works if you have control over all the graphics being used, and are not showing any video.
  • Use the ‘small 4:3 option’ in your projector menu to shrink the image. Some projectors (especially those with aspect ratio controls for 16:9 or 4:3) allow you to select a ‘small 4:3’ mode that shrinks the image to a smaller area. It uses less pixels so you lose some clarity but you don’t overscan the screen (and it works for video too)
  • Use the ‘Picture in picture’ option in your video mixer to crop the image. This is dependent on your mixer having this option and being able to use it to crop the image. It severely limits what else you can do on your mixer, so is pretty much a last resort.
  • Use centre wipe to mask edges. You can achieve a partial wipe to crop off the edges of a bit of video. This assumes that there is nothing critical that needs to be seen in the border of the image.

If the projector is forced to be too near to the screen:

This is much harder to deal with:

  • Use a smaller screen. Obvious, but don’t rule out just swapping in a smaller screen. If you are only going to fill part of a bigger screen, why not just use a smaller one.
     
  • Use a mirror. You may want to experiment with mirrors, but remember that unless you have a very expensive front surface mirror (the silvered layer is on the front of the glass, not the rear) you will end up with a slight double image. Purists will shriek in horror at this suggestion, but I have used a normal bathroom mirror to bounce some song words from a narrow balcony up onto the back wall of a church for a choir to see while performing. Worked fine for that application.
  • Turn screen on side and drape the bottom. Remember that all screens can be turned to give a smaller horizontal width, assuming that the unused part can either be hidden or draped. Remember that you can go up or down to get more distance from the screen Sometimes placing the projector on the floor will give you enough distance, while not obscuring sightlines. You can use keystone correction to correct for the skewing effect If the projector is forced too far off to the side.
  • You can use horizontal keystone correction. Normally this will only let you get the projector in line with one or other vertical edge of the screen. Not much but it might be enough.
  • Pre-warp graphics or video. You can warp the images so that when they are projected they correct for the distortion. If you have to show powerpoint or keynote slides you can export slides to .JPG and warp in a new presentation. Video can be warped in most NLE’s but of course you will have to render the whole video clip, once you have worked out the right amount of distortion.

So there you go. All is not lost.

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