Are Fresnel lenses worth it?

[Bursar]

I don't think I'm going to be able to afford to get a decent sized screen in my cabinet for a while, so was planning on using a PC monitor (either 17" or 20", depending on what I can get my hands on). Is it worth getting a Fresnel lens and fitting it over the screen?

The ridges on the lens look quite prominent, and I'm worried it might lower the image quality far too much. Has anyone tried this, and if so, how did it work out for you?

[MameFan]

I tried one (finding one for $2 at a thrift store)... I did and didn't like it.

Perhaps because of it's age (the box graphics indicated a late 60's/early 70's manufacture date) it isn't as good as the current ones.

First, it DID increase the size of the picture, and quite well in fact.

However, it ended up basically making streaks towards the center of the monitor out of everythign that was lit.

(The BEST example of what I mean is, take a look at how Tempest draws its screens.. A tiny representation of the screen starts in the center of the screen, and then "explodes" twoards you getting bigger (e.g. "warp speed" )   Think of this now with PacMan loaded up... you can see traces from the "big" picture on the lens back towards the screen in the original position.)

Its annoying, and of course the whole thing looks sorta 3D then, and it shifts with your eyes as you move from the center of the screen.

(You dont notice this as much on a TV picture because the screen isn't so full of sharp, distinct graphics, rather smooth pictures)

Plus it gets distorted if you move too far off of center (e.g if a second person is standing watching you play from the side of the cabinet, it will be about 50% unviewable.)

Therefore this would suck for 2 player cooperative/competetive games (e.g. original mario bros).

Like I said, perhaps newer lenses are made better, but I was not happy with the results from a 19" monitor and an early 70's 25" version of the lens.

[Bursar]

Thanks for that.

I've been searching around, and there seem to be very few photos of these things in action. Plenty of 'make your own 100" TV screen' sites, but they are big on fancy words, and short on actual results.

I also noticed with interest that mitsubishi TVs use a fresnel lens! I would imagine theirs is scientifically designed from the best components, but if they use them actually inside a TV, then they must work fairly well.

Maybe newer fresnel lenses are better. I'd just like to hear from people that have used them before I decide to get one.

[D10]

I have tried to use one, and try being the key. I could not get results that I was looking for. In my testing to get the focal length right the lens was all most 12" away from the monitor. Even then the picture quality was pretty poor.

Like I said this was just my experience others might have had better luck.

[Bursar]

Hmmm, maybe I'll just ditch that idea then. If they worked fairly well, it would have been a great way to get a large looking screen for little money. Ah well.

[MameFan]

I think the newer, more expensive ones (from legit sites, not the "all hype" sites) have a much finer machining to them with the ridges closes together and not as thick (at least compared to my 30 year old test piece).

If you could find one that was made for SMALL magnification (e.g. a focal length of say 4"  (e.g. ideal placement is 4" in front of the screen) to increase the size by 6"-- that would make a 19" computer monitor a 25" one, meaning that vertical games would "appear" a full 19" diagonal when centered in the screen.

With a higher quality piece (e.g. I've seen some better quality "book page magnefiers" for a few bucks than the big TV ones) you might find one that doesn't exhibit the problems I mentioned before.  

A friend of mine paid about $35 for one a year ago.. I think he had fewer problems, but it still wan't perfect.

[Ken Layton]

In my opinion you're just throwing your money away on those things.

[MTPPC]

I need to bring this thread back from almost 10 years dead. I am considering using a fresnel lens from a "modern" projection TV in front of a 19" 4:3 LCD Monitor in the backbox of a pinball simulator. What are my odds of success? What I really need is about a 32" 4:3 monitor. This is my goal. Is there any other kind of solution? I have a small collection of fresnel lenses to try it with, but they are not in hand right now.

[MTPPC]

My experimentation is done and the concept is interesting, but the results are sub-par. Here is a with and without at 7" behind the lens:





Here is a with and without at 17" behind the lens:





Now you know.

[rCadeGaming]

I think it would work great for underwater games.  Really authentic look.  Now you just need three monitors and three of those lenses side by side to play Darius.