Did someone mention that they found some sort of moire pattern when they used unsplit fresnels together with no space between them.. or was this only with lens shifting.
So much info, such a useless search option (no offense to the website builder)
-Mark
Full Version: Unsplit Fresnel Question
I do believe it causes some odd effects if you do not space them. I forgot where I read that, lol but if I find it again I'll be sure to link it for ya.
If you have seperate collimator and field fresnel, and put those together to create Unsplit design you must be carefull to align them corretly. or it will cause moire pattern.
Well depending on how far you place the LCD from the fresnels, it might not be an issue at all since you will only be focusing on the LCD an not the fresnels. At least that's my experience with Unsplit design.
/Martin
Well depending on how far you place the LCD from the fresnels, it might not be an issue at all since you will only be focusing on the LCD an not the fresnels. At least that's my experience with Unsplit design.
/Martin
Sandwiching fresnels with no space in between requires ultra-precise alignment and is generally not recommended.
hmmm . . well precise is not a word I'd use to describe my building skills. I think I'll just toss a 3mm sheet of glass in between to be safe. Thanks for the help.
-Mark
-Mark
Air is better and use a little more separation as well. The more material-to-material interfaces the more losses and potential artifacts you experience.
without proper spacing and assuming less than perfect alignment, you will get a star burst pattern in your projection. I had my fresnels spaced ~7mm at first and I had a bad star pattern even though my fresnels were aligned pretty well. I increased the distance to ~12mm and its 95% gone. 3mm spacing is not enough to combat mis-alignment in my opinion.
Is there any benefit to aligning and securing the fresnels face to face? I know that in my own project I have had some trouble with dust settling on some of the surfaces - having 'sealed optics' in this sense might not be a bad thing- provided that the alignment problem can be overcome.
QUOTE (thatmarkguy @ Feb 21 2007, 10:21 PM) 
Did someone mention that they found some sort of moire pattern when they used unsplit fresnels together with no space between them.. or was this only with lens shifting.
So much info, such a useless search option (no offense to the website builder)
-Mark
So much info, such a useless search option (no offense to the website builder)
-Mark
When I found the forum's internal search less than useful, Google can be of some help with a site search.
For example...
http://www.google.ca/search?q=unsplit+ques...ab.com%2Fforums
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