Different Fresnel Lenses, Different Capabilities - Different TVs

A quick demonstration of the difference between a Spot Lens and a Linear Lens, both of which are used in big screen TVs. The punchline being spot lenses can do everything that a linear lens can, and much more. Much higher temperatures achieved with a spot lens.
The spot lens in this vid was taken out of the tv in this video • Solar Fried Hot Dogs w... at 1:15 into the vid. I can't remember the make and model, but you can at least see the type of console tv that it came out of.

[@srussert28]

I lucked out and have a liner lens and the focal point is almost exactly the size of a hot dog. We threw together a frame and took it out for a science project at a local Zoo. We cooked two pack of hot dogs fairly quickly and, if turned right, they came out perfect. Next focus it on a black pipe to distill water. We were boiling water in a small can but I know we can show the kids real water purification. This is a great project.

[@oneangrygoy]

Can't believe this didn't get a like in 10 years. That sound perfect to me dude.

[@srussert28]

@@oneangrygoy Thanks for the like. That lens has since cooked hundreds of hotdogs with radiant heat. I also have a few point lenses and let kids melt pennies and then drop the molten metal in another pan so they have a unique souvenir to remind them of the power of solar.

[@lookingatoceanwaves]

I have a cook type lens, and I got my 14 inch cast iron skillet up to only 290 degrees. Then I flipped the lens over and got it up to 490 degrees. Seems one side toward the sun is better than the other.

[@peterhansen767]

Interessant, danke für den Tipp.

[@strhaivenswr]

Yes because of the way the lens works a close up drawing would be a better way to understand you see it as a flat sheet with concentric circles feom the edges to the center each ring is round on the outside edge sort of dome and the inside edge of each ring is more flat and angles in toward the the next ring focusing all of the energy into the center the smaller the focus dot the hotter it will be. Now if tou flip the lens it takes a tiny micro dot of light and magnifies it into thw image you see on the screen of that particular type of TV of course.

[@JoshuaSHanson]

Thanks for taking the time to make this video, the knowledge of different types of fresnel lenses is really helpful for a beginner like myself.

[@boomstickman71]

"You're not gonna know what lens you've got until you break it out, put it in the sun, and have a look." Well, we COULD know, if you'd taken the time to write down which TV each lens came out of, or bother to TELL us if you knew.

[@kidsworld3881]

Fresnel lenses are the best, I think that!! But I don’t know actually which TV had fresnel Lenses. Any body has Information?

[@drewlop]

Kids World I think pretty much any rear projection TV will have some kind of fresnel lens. They’re the big kind that sit on the floor

[@DaveSmith-ke5ik]

@The Nech out of 24 TVs I've pulled apart, so far I have 2 spot lenses.

[@jessewilson8676]

The only ones I’ve ever found were in projection screen TVs

[@rswow]

@@DaveSmith-ke5ik Spot lenses from which TVs?

[@WorldOfWonder66]

I can see a lot of potential uses for these . Thank you for sharing this

[@greatestunknown]

Thanks for this video. I've collected lenses in the past when I used to work for a TV manufacturer. I got rid of them all ): . Now I'm hunting the alleys for them, but at least now I know a little bit of what I'm looking for thanks to you.

[@stognoster]

This is just amazing stuff! What a practical application of recycled obsolete junk. Saw one of those TVs on the side of the road a few months back. If only I'd seen your vids back then! Can't wait to try this. Thanks for uploading. The instruction video on making the frame will be really helpful too.

[@BarbaraInspires17]

Thank you for making this video. I'm switching things around at home to become more off grid. This is a great idea! In the process of making a food forrest.

[@greyhoundfriend123]

That was really amazing. I saw the framing, the awesome spot lens and I can't wait to watch the actual cooking!

[@WayneEarls]

I accidentally got one of these lenses out of my old big screen, then I saw your videos... Now I'm glad i kept it.

[@rc9266]

yeah? which TV was that?

[@bcmasur]

They can all be "SPOT LENSES" if you made frames that were tuneable. For example, try pushing in the center of the lens one way or the other and see how it changes the focal point.

[@brentonihms]

Great video. Over and beyond.

[@dplj4428]

The fresnel demonstration explains how I almost cooked at the nus stop. The sun was directed off a building across the street. Some building code discourage that type of building cladding. Enjoyed video. Gave me a few ideas.

[@brotherreverb]

Thanks. I'll see how it goes. Looking for more of them to scoop up.

[@HighwayBrickery]

Woo-hoo!!! I might have just scored a dozen of these lenses from my local recycle plant! Guy was very helpful; when I go back on Monday hopefully he'll have them all ready. And hopefully I'll score at least one coin-melter!

[@tomlauris]

Thanks for showing the differences. I was lucky and my first lens was a spot lens from a 90's TV (almost square, wooden frame). It can focus the sunlight to a spot the size of a coin and it's fun to scorch stuff with it, but after 2..3 months of using it I can say it has some disadvantages when it comes to cooking. It can easily destroy glass lids and other materials, it even burst the heat resistant glass panel I dismantled from an old oven (the cover for an insulated box I built). Today I got a linear lens from a newer all-plastic widescreen TV which focuses the sunlight only to a spot the size of a pot. Hope that will be less dangerous for my cooking equipment 😁

[@cosmicallyderived]

Exactly sometimes less is more. It all boils down to your application.

[@nickmonk7945]

@@cosmicallyderived clever pun, “all boils down “ 😂🤙

[@nickmonk7945]

So how did it turn out, one year later?

[@tomlauris]

@@nickmonk7945 The linear lens is just as good as the spot lens when it comes to cooking, but I still managed to destroy a window glass panel with it. Now I'm using iron cookware and tempered glass and try not to focus it on the glass too much. Only thing that got destroyed from the heat and moisture so far was the wooden box in the 2nd video. By the end of the summer it got warped so much to the point where it became unusable. Next time I will use metal. Spot lens video: "Solar cooking: Boiling eggs with TV Fresnel lens" Linear lens video: "Solar cooking: Bone broth with TV Fresnel lens"

[@nickmonk7945]

@@tomlauris cool thanks for your reply 👍

[@MrMrwilem]

Thanks for sharing this side by side...very good info.

[@tortoiseshellcountenance2621]

nice vid, LOVE THE SHIRT!!

[@goldenalex]

Its great for cookin' !

[@starfawnoni]

Thank you for this great info on the lens.

[@nostradomassbrother]

Thanks for the info, good to know when I go hunting. And nice shirt!

[@gizmoguyar]

I really appreciate this video. I've been looking for TVs for a while now, but I can't seem to find one that has a good lens. At least now I know why! Thanks!

[@shelleywalker5465]

phenomenal. guy at work told me about this. all over the em. prep. stuff. lookin' for the right ol' TV now (crap, gave away or sold for zip several over the past 10 years!) thanks!

[@ewmegoolies]

Great video and what about this? On the "crappy" lenses how about a slight bend in the frame to try and tighten up the line you were getting?

[@edcarson3113]

Excellent information and research friend.

[@donktheclown]

Awesome info and great job, thanks. Can you tell us which tv you got the clear lens from so we may be on the look-out for that particular one??

[@BucketListBadass]

Excellent video.

[@OJA23122011]

Thanks for sharing your experience keep up the good work

[@MrJasonharrelson]

Have you experimented adding an offset parabolic mirror under the lenses that produce diffused light pattern? With the right parabola you can focus more light from that 60" than any of the other lenses.

[@savgal1211]

GREAT Channel!! Subbed, LOVE it, thanks for sharing your knowledge, Sir!

[@ipaint00]

Great video! So, do you have any input on what type of lens and size are good for lighting a fire and cooking, if need be? I'm looking to buy one that's versatile. Thank you in advance.

[@kasdfg776]

Seems like it would be a good idea to have one of each, though. The lame one as stated for cooking, warming things or places, etc. You wouldn't have to keep such a close eye on it. Great video!

[@obduliocerceno4984]

Good tips!!! Thanks for sharing. Thumbs up!!1

[@bccritters]

Did you try turning the "bad" lenses around, or flipping them over? The one that I have works differently depending on its orientation.

[@ericbullard459]

Took four tv's apart before finding a spot lens in a 50" Sony. Kept the others for cooking with the boy scouts.

[@myemail9131]

What year was your SONY? I have a Mitsubishi DLP, WD 60738 model, bought in 2011 - and IDK if I have a Fresnel lens as it is a 60" rear projection TV?

[@DaveSmith-ke5ik]

@@myemail9131 I've pulled 3 dlps apart. Non of them were spot

[@dmithsmith5880]

Nice lense collection !.. My best one is a 36"x 24" spot fresnel and the thing is absolutely vicious. It will drop a 5/8" dia bead at 30" focal point and straight up turns sawzall blades into sparklers.

[@boltofthunder92]

Very helpful. Although I would like to know how one could look for clues as to which TV has what?

[@EndTheFedRes]

Question: Who makes the 'spot' lenses? Can you buy them? Secondly is the focal point cone shaped from the lens to the focal point? Thirdly is the energy the same say from the focal point, to 8 inches up? (Same amount of thermal energy, just more displaced?)

[@roberthoward5015]

Thank you sir.. I thought I had done something wrong… you answered all my questions…

[@victorfox9623]

Would it work if you placed one lense on another lense? I wonder if there's a sweet spot that could improve the performance of the bad ones.

[@gregsbest]

Good effort there. I wonder what company uses the best spot fresnel lens's ? tx.

[@iyoutome]

Hey bro, thanks for the info. So cool.

[@jimvanbelkum1082]

OK - just guessing here. Older Big Screen Projection TVs had a square picture, while newer units have a WideScreen 16:9 aspect ratio. Since the newer ones are wider, I would assume they would need the Linear Lens in order to spread the image across the wide screen. So, I think I'm going to look for older - square-screened projection TVs in hopes of getting a Spot Lens.

[@Weaton777]

8 yrs later ..lol .. curious. What did you find out?

[@devinmccloud]

Any idea if an RCA 42" TV Model: p46920bl lens is a spot lens? Any information would be appreciated greatly! The screen looks pretty square.

[@walkingawayman3146]

good to know information before i try to get one of these but i have to wonder though, if some of the weaker lenses will help produce more power out of a solar panel if focused down on one? it may put more of a practical use to the lenses you don't like.

[@cmororton]

Great video brother

[@steveec9704]

Thanks man great info! Jeff P is the man!

[@edwinahaskell]

Outstanding information and concise demonstration. Question: The milkiness in these lenses - Is it on the smooth side and can it be buffed out to make a clearer lens or is it just junk in the plastic? Also, the linear lenses - Can they be used safely for natural lighting in an indoor greenhouse if you bounce the light off a mirror assuming you have a heliostat? Thanks in advance for your time.

[@darrellpidgeon6440]

The overhead projector I took apart years ago had a nice fresnel inside. Very hot spot. The projector is now almost a thing of the past in most places, I suppose.

[@stvian]

? I took apart an old cellphone with an LCD screen and when you break the screen apart there was like three layers of lenses and two of diffusers. I then found one of the lenses that did a line focus and made a flashlight cover with it so that I can either have a line of light either up or down or side to side. My question is these lenses all acted different with the different sides placed toward the light, so do these larger lenses act different with which side faces the sun in how they focus??

[@steviejacko]

Great video , thank you for sharing :)

[@Zalamedas]

What if you take a linear fresnel lens and get some other smaller focusing lens? Because the idea is to bring all the light in the lens area and focus it into the smallest possible point. Well.. focus the linear beam into something smaller. Would it work or I don't know a crap?

[@Platininis]

Nice vid! Could you tell the TV brand that you took the lens from? (the second with the best sport concentration)

[@paulsmith6182]

Did you try a page magnifying Fresnel at the soft focal point to achieve a sharper focus?

[@JandjacresNet]

Have you ever compiled a list of which brands tend to have the better lens, or which models?

[@jonathanasber1730]

+Shawn Hawkins I used to sell those TV's and the diamond series . I'm old . lol

[@Russell218]

I dismantled a Sony KDS-60A2020 today and the lens is poop. Even polishing the backside won't make it fully transparent.

[@OffGridInvestor]

I just tore into a rear projection TV that a trucking company near my work was chucking out. Stupidly enough, I ripped straight in not realising how close they are to the surface. But it's barely bigger than the mirror in the back of the tv. I am barely getting anything although only one side got cracked off a few inches in. Its an old LG.

[@koifish8554]

awesome ty for the ideas i love this stuff

[@ParaglidingManiac]

Hi! What advises can you give, when buying A4 size fresnel lens from Ebay? Will it be any good if it's linear? Thank you!

[@imanultrastarwarrior801]

holy crap this is friken awesome !!!!!!!:)

[@wkham2664]

Wow, this video was 12 years ago. If you are still around and remember, what model of the TV that second Fresnel lens was from?

[@lothre]

Do you have the model, brand and sizes of the TV's you have scored spot lenses from? would help speed the search for us if we could narrow our searches and decrease gas consumption/time used on TV's with the linear lenses. Great video by the way!

[@dwillbecancelledsoon4086]

Did you ever find one a decade ago?

[@Juan-ce4ei]

Thanks for this very interesting share. Take care of yourself man.

[@maritzadomeneck8955]

I wonder if you could use the less powerful lens to use at your home Windows to heat up your home.? can you do a video on that?

[@robertmiller323]

you rock! you answered all Q's.if there was a tip button i would ......tanks!

[@Projecticles]

Nice sound effects bra, and watch out those light amplifiers get hot, ZOOOHHHH!

[@debrabrooks6138]

A solar oven use is a great idea, I would think a metal box with the lens on the top. I thought of another great use for this idea, a solar heater for your home! just like the blackened tin can idea with a vent duct going into a window, this would prove to be of great use in very cold regions indeed! What about in a desaltation method? I would think this could make a wonderful mini plant for those who need it, though have to figure separation tanks and evaporative tank.

[@mace1141]

GOOD MOVIE! Love the no BS! Thanks

[@flyingtoohigh]

very educational. thanks

[@jeroendonker]

Interesting stuff. I've got a linear lens, but it's mounted in a curved frame so the lens itself is bent, giving it a pretty concentrated focal point…

[@kimphillips6161]

How munch can you curve the lenz? Can you encapsulate the lens into a small bucket? With a hole in the bottom?? Maybe like a large flashlight with an option on the back to close the lens. This might enable a person to pinpoint Chanel the light and effect, maybe? I just found this process today and am fascinated.

[@rosethornil]

Thanks so much! Very helpful!! :)

[@AndrewBaezaShogunMaster]

okay so say youre in a dark room do these things work with no sunlight? is there an alternative that can work in the dark and how effectively? i say your brass melting video, or just a brass melting video rather not too sure on the origin

[@warrenpamment]

so by the looks of it these come from flat screen TV's do the old type tvs work as well with the round lense?

[@mikemarch5480]

that was awesome!!

[@sh55555]

Thanks for the info!

[@LC-ue6mp]

Finally, I've found you!!!

[@LifeGeneralist]

Greetings from India! I liked your video very much. I never knew these lenses were so different, and I'm in love with the 2nd lens you showed. :) Can you let me know what were the weather parameters during this experiment. I mean, the place you stay, which time of they year(season) and what time of the day it was? I'm pretty much doing all these similar tests on acrylic fresnel lens

[@atacke3736]

Great video. Not sure if these are plastic or glass but if they are plastic have you tried bowing the linear ones a bit to see if they will come to a point? It shouldn't take much Just a thought or maybe stacking at 90 degrees spaced just a bit apart? Thanks.

[@Toca_waffle843]

thinking outside the box

[@hakimartsmarineartsscene3816]

fencekid thanks 4 the video , wonder if you ship one of this to the UK? want 2 buy one?

[@TheLoneace69]

I'm going to make one here shortly . i only need low temps to solarize my garden soil. rather than wait six weeks with the traditional method I think I can do it in an afternoon, if I have a good lens. I hope by the time I get it together its one of the better ones for later projects. Is the lens easy to cut? I have a 45" with a crack in it. I want to cut the crack out and use the remainder.

[@mrcustomblue]

It also appears that your best lens is also a lot clearer too. The others looked hazy at least on the video.

[@AndrewBaezaShogunMaster]

@fencekid whats the name, what are the specifications on the final piece you showed? I'm sorry i have an audio issue with my pc please forgive this. i am deeply interested in this technology. please respond

[@stevewalker9888]

So I’ve done as you suggest and have a few lenses. However each tv has 2 lenses and defused lense. Which one are you using to do that with ?

[@rlew8095]

These are cool, I want one!

[@hdrjunkie]

a cabinet made of that particle, MDF type wood? I just got mitshubihi 55" yesterday, took the lenses out but didnt get to take the actual fresnel lens out yet....hopefully its a spot lens.

[@szaki]

Got my lens out of a slide projector, much smaller than yours from TV, but still very powerful.

[@jdfrmr1]

What brand was the projector?

[@wtimber]

Good info! Wish we had a list of good sources

[@bluecapone]

The spot lens looked really clear like glass... Do you think that might be a good way to tell what you've got?? I gotta get me one of these!

[@triumphmanful]

Do the newer flat screens have a fresnel lens. People are already tossing them here. I have made a few into light boxes . Thanks

[@fencekid]

thanx for the cool comment man, that shirt, I picked up on amazon. One of my faves

[@joemartin2085]

Does it matter which way the lens is setting? "Up and down or from side to side"? And do I have to use the whole lens or can I cut it to any size I choose?

[@ZPDSurvival]

I just want to cook. Melting point is for something else. Thanks for the demo. Cool.

[@mitchtooaye]

thanks for the vid man totaly explains why my first lens seems to suck arse.... will try again

[@dariogonzalez6249]

Hello, im looking for a way to dry soil for crushing can i use a radiant system & letting one of this heat the water also of course using a circulating pump?

[@carolannwrightbentley12]

Hay thanks for telling us what model those were you think your going to keep them all to your self? Cl.

[@oldladyme]

THANK YOU GREAT VIDEO AWESOME...

[@tfcig2019]

That 4 vid. Much enjoyed info given. So the different brand of tvs do not necessarily determine the type of lens? Carport where we had to move contained a huge Sony TV. Works, just needs an antenna. Unfortunately, too many trees where we moved, to get decent reception. Was going to chunk it, until came across vids using big TV screens to cook/melt objects. Curious to know if you layered between wood pieces or affixed to one side for stability/use?

[@1943Grandpa]

What happens if you double two lenses at different distances apart?

[@vagt4603]

do you know of certain models to look out for that have the spot lens?

[@ensotao1]

hi, I just acquired a toshiba cinema series and want to use the whole thing. i took the lenses out and will use for many things but I want the lights out as well and I was wondering if you knew what type of fluid is in them ( theres a warning about leakage). Gonna use the body as a stage for puppet shows. Thanks.

[@Devoliver144]

+Darrell Anderson I know you asked 3 months ago but if you didn't figure out by now it's either mineral oil or glycerin

[@bakugosrage8976]

Thanks fence kid. I was looking into a way to melt some glass for a house project and if I get one of those spot lense it will make the job easy as pie.

[@005Amergin]

Love this..do you still have the video where you show how you build them ? You could teach folks for a small fee how to built them A -covers your bills/time labor cost B -helping community! Lots of folks who are now converting vans to live in year round may find them very useful to use while travelling- alot of folks don't like propane anymore! Ty!

[@rkaag99]

if you used the 'line' focus lens on a length of black pipe, would it get hot enough for a water heater?