So I ordered my lenses. I got the two pro Fresnels and the standard triplet.

Anyhow, when I got the package, one of the lenses had a corner broken off, and I was wondering what the best thing to do now would be. It seems like there is only a quarter inch broken off, and i have found the broken piece, but I'm not sure it will effect my projector.

What do you guys think? should I return that lens for a replacement? or should I just use it with the broken corner?

I have a 17" monitor and the lenses are good up to something like 19" or higher.

A broken corner will not hurt at all. Remember that you will have to build a frame around the edge anyway and it will remove more than 1/4" all the way around.

Do you know that the standard triplet doesn't work with the pro lenses?





After you have done a trial setup, you may find that you will need to trim down the fresnel to optimise your box size anyway. Just make sure there isn't a crack in the fresnel that might spread.

That doesn't make any sense to me, because they both have a focal point of whatever mm. Since they both have their respective focal points, you can find the place that best suits the lenses you are going to use.

Please inform me if these will NOT work with each other. I see no reason why they won't especially because the ProLensTriplet has a different focal lenth then the lenses, it's just that the Standard has even more difference.

I am willing to learn, but there is precious little info about mixing and matching lenses, especially the issue with it not working, they should note that in the store if that's the case, because the price of the pro lens is prohibitive.

Cullen (BTW, I'm also not using the standard 400W lamp, i'm using 5 5W LEDs, looking to be about 750 Lumens before the LCD panel.)

To explain:

The distance of the LCD to Triplet will be determined by the triplets focal length, the LCD size, and the desired size of the projected image. There is only one combination of these factors that will allow you proper focus.

As an example:
17" LCD, LL Standard triplet (320mm FL) and a desired screen size of 100".

LCD to Triplet distance = 375mm
Triplet to Screen distance = ~7.25 ft

The standard field fresnel focal lenght is 317mm, which when placed near the LCD will focus light into the triplet rather effectively. The pro field fresnel focal length is 650mm, which is much too long for this setup and there will be a lot of light spilled around the triplet, which means it won't make it to the screen.

First, the pro lens kit is specifically mentioned as being for 17" LCD's, and the standard lens kit for 15".
Yes, other's have used the standard triplet (320mm FL) due to not wanting to spend the money for the pro triplet, but in that case, they source a different field fresnel that is physically larger in size. (the pro collimating fresnel and standard collimating fresnel both have a 220mm FL, the only difference is the physical size) At the moment 3dlens.com is the place to get a 330mm FL fresnel, which is large enough to cover a 17" LCD panel, and has the 330mm FL, which will be a good match for the 320mm FL triplet.

So, basically to make your setup "correct" would be to purchase a 330mm FL fresnel from 3dlens.com (I believe it is now called an "F330") and your setup will be complete... and you can sell your pro 650mm field fresnel in the trading post area.

You should also understand that there are other shortcomings to using the standard triplet with a 17" LCD. First, you won't be able to get perfect corner to corner focus using as the FOV is designed with a maximum panel size of 15" in mind. The "throw" (distance from triplet to screen) is also very short with this setup, and will require keystoning for floor or ceiling mounting. The short throw and required keystoning will mean a large keystone angle, which will further reduce focusing ability across the entire screen. Others have done this and been satisfied with the results, but I thought I should mention this to you now.

cheers,
gs

Thanks *thumbs up* that makes sense.

I'd like to try it before I go and spend another $30 bucks on the "right" lens (well I suppose it is more correct). So we're going to build a jig so that we can move all the seperate pieces around so that I can figure out what the right lenths are. thanks for the help.

Cullen