This is my first post in the lumenlab forums. First of all, I want to say that I am from Mexico so my first language is spanish so please excuse my mistakes.

Well, I want to make a PJ so I am in the design and planning fase. I read the guide several times and also read many posts in the forum. I want to hang my PJ from the ceiling and I read about the keystone effect cause by the angle of the projection.

So this is my idea for a autokeystoning system and I want to know I it will work. I hope I can explain it well, it will be hard for me so if you have any question please let me know.

Please refer to the attached image. So the idea is simple, to use a pivot in the upper part of the collector fresnel so the lower part will have a free forward or backward movement of 15 degrees. In theory the collector fresnel will be in a perfect vertical position and correct the keystone effect. An external knob will be place outside the PJ case to mantain the angle.

Will it work? Does anyone tried to do this before?

Thx

Yep. That's a very common method of keystone correction. I use that exact method in my projector.

well if you have read many post here you would notice that 90% of the projectors are like this, look at the plogs....
and there is a whole post just for keystone correction.

I think that he's talking about linking the fresnel to the hanger mount so that it would swivel as the projector is tilted. It's not a bad idea but if you were to lock it at the bottom you would need a strong and ridgid assembly holding the fresnel. This would only be useful if you planned on moving the PJ foreward and back. Otherwise it's probably more trouble than its worth because you would only set it once.

It could work as well as the gravity keystone method. Personally I would want independant adjustment in case I needed to tilt the panel and triplet.

That is right DeathRay64, that´s what I tried to explain. In the future I want to build a PJ for a friend´s rock band that they want to use in their "local concerts" so maybe they need to correct the keystone everytime they play. I want to try this design in my PJ to see if it work and not to experimente with my friends PJ. Thanks for your replies.

if they have anyother lighting going its not going to work well for that. just to let you know this is going to have to be in a dark room.

Thanks gguertin145, I´ll keep this in mind. Does this happen too with a commercial PJ? I´ve seen some night clubs (with a relative amount of light) that have PJ´s showing some images that doesn´t look awsome but they are alright.

The Lumenlab design does not have the lumen output that many commercial PJ's have. I doubt you'd be able to throw enough light vs. stage lighting. Possibly from behind a screen though...