So I finally finished my PRO unsplit 17'' LCD straight shooter projector. The image is great but when I am close to the screen the corners are not as focused as the center. The pixels bleed towards the center a little and I can see rings (probally the frensel rings). The distance between the front frensel and LCD is about 10mm so I dont think this is the problem. I did do the PRO Lens modification but I used a 5mm spacer instead of the recommend 3mm... (I think ill try this after dinner). This may be the problem but I am not entirely sure. If anyone could shed some light on my problem that would be most excellent!

Some pictures of your screen and enclosure would be helpful.

Fresnel rings on the screen usually mean that a fresnel is too close to your LCD. Try moving your front fresnel 20mm away from the LCD.
Do you have an even focus across the entire screen? Do you see the entire fresnel ring or just parts? There could be an alignment issue.

the rings only occur near the the corners AND it is slightly out of focus/ pixels bleed towards the center. I'll find my camera and take a few pictures soon. Ill try moving the LCD right now

Did you try the lens BEFORE modding? If so, how did things look then?

Well, as soon as you've modified the pro lens, bets are off. If you didn't reassemble it precisely correctly (You mentioned a larger spacer) then your lens focal plane may not be flat any longer.

I can verify that it's certainly possible to get excellent corner-to-corner focus from the pro lens exactly as it ships. The modification is done for (as far as I can tell) very short throows.

What is likely happening is that your lens is no longer focusing on a flat plane. It appears that the triplet's EFL is different at the corners than at the center, which means that it's starting to bring the fresnel (10mm further away) into focus near the corners. In this case, there is no way to ever get clear corner to corner focus with your lens as it currently is.

Before the mod, the right corner had a slight pincushion effect and out of focus so I tried out the mod. The mod seemed to fix the focus but the frensel lines showed and bleeding occured towards the center. What SupraGuy is saying seems to be correct so I switched back to my original setup.

After switching back to the original set up of the PRO lens the right corner still has a slight pincushion effect and out of focus. The left corner has perfect focus. Hopefully moving my lens around didn't mess up my focal plane as SupraGuy said but I still have the same effect now before modding the lens.

So what could be causing the right corner to have pincushion and out of focus. (placing a piece of paper about 1ft in front of my screen gives perfect focus in the right corner...) and everything seems to be aligned.

my screen kind of looks like this... with ORIGINAL PRO lens set up
Click to view attachment

FYI: When you use MS Paint, the file will save as a .bmp by default. You can choose to save the file as another format, like a .gif or .jpg. This will decrease the file size (since .bmp's are usually huge) and you'll be able to attach it as a picture instead of a file.

Here's your picture.

Sounds like an alignment problem from before you did the mod. Similar symptoms before and after. Have you tried fiddling with your components and triple checking everything?

Thanks Quasi_Mojo, I completely forgot when I made it.
Yeah i moved everything around at almost every angle looking for any small changes in focus for that corner with no luck. I think the frame of fresnel might be too tight and causing it to bend.

Do the distortions/abberations change with temperature or stay the same? The difference could be minimal so may not be readily seen. Also, have you tried simply reaching in there (maybe with some powder free synthetic - latex or nitrile - or cotton gloves - or just a really clean finger*) and pushing on the fresnel(s) to see if you can alter the distortions/abberations?

*my fingers are usually booger covered or WORSE!!!

Try seeing if you can shift the lens alignment around a bit to get a more perfect focus. If it's just happining in one corner then I can pretty much guarantee that it's an alignment issue. You can also try rotating the lens 120 degrees (Basically shift everything around to the next stop for the 3 screw holes.) If the distortion moves with the lens, then the issue is with the lenses to the barrel. Maybe some debris in the lens from bing moved? If the distortion stays in the same place, then it's the alignment of either the LCD or the lens. Loosen the screws a bit and try moving the lens around a bit. A very minor change will make for fairly largish changes in the focal plane.

@trs105: I'd be willing to bet that this is either your projector is not straight on to the projection screen, your lens is off center compared to the LCD, or your LCD is misaligned, and is not perpendicular to the principal axis.

Also note that the longer the throw, the smaller the LCD must be. I measured that a 19" LCD would be fine, but that was for a throw of only 9' For my current throw of 14', I can only verify that a 17" panel is fine, since I removed the lens shift component.