Sunday, May 22, 2011

Size Does Matter!

I started working out the dimensions and realized that first I needed to know the focal distance of the projector. After playing with the projector I'm planning on using I quickly realized a few things. Projectors are made to project LARGE and not straight ahead. They can also put out some serious heat. The projector I have has a minimum focal distance of 50 inches and throws a picture 32 inches wide. Not ideal for what I have in mind. However, I don't want to make any drastic/permanent alterations to the optics because I would like to be able to still use it for movies. While I was pondering my options I remembered a set of macro lenses I bought for my K-1000 some 20 years ago. (Does anybody else remember when cameras actually used film?) I played with the lenses and found that by placing them directly in front of the projector lens I could drastically shorten the throw distance (and image size). By using the +4 lens the distance was reduced to about 7 inches from the front of the projector and the image size could be adjusted with the zoom to 6 inches wide. The best part is that I don't have to alter the projector in any way. I'll get a filter adapter and rig up something removable to hold it in place. I'm also going to have to be careful not to block the cooling vents in the front. If I was going to place the projector vertically under the resin tray it would be blasting hot air right at it and would get the resin quite warm in no time. I will avoid that by placing the projector behind and horizontally but may have to use a supplemental fan to move all that heat away from the projector.

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