Do all rear projection TVs have a fresnel lens? Update: Evil laugh!!!!

[letat]

Anbody know do Sony kp-41px1 have fresnel lens inside? I can get it but its around 50miles avay so i dont wana go if it is not inside 🙂

 

[IronWing]

Anbody know do Sony kp-41px1 have fresnel lens inside? I can get it but its around 50miles avay so i dont wana go if it is not inside 🙂

I can't say yes with absolute certainty, but yes that model should have a fresnel lens.

 

[DrPizza]

Personally, before I aimed my DSLR at something that hot, I'd stick a ultraviolet filter (is the ultraviolet partially reflected from the surface?) and an infrared filter on the lens. The uV filters are fairly common as an inexpensive means to protect the lens surface from any scratches, etc. - clean the filter, not the lens.

 

[IronWing]

Personally, before I aimed my DSLR at something that hot, I'd stick a ultraviolet filter (is the ultraviolet partially reflected from the surface?) and an infrared filter on the lens. The uV filters are fairly common as an inexpensive means to protect the lens surface from any scratches, etc. - clean the filter, not the lens.

The camera had a UV(0) filter mounted.

 

[smagzilla]

Is there a list anywhere to find out the quality and actual existance of fresnel lenses in tv's based on make/model and size? that would be dope!

 

[Red Squirrel]

These look super fun to play with. I want one!

If you can put a grid of copper pipe slightly out of the focus (don't want to melt it) and pass water through it, it would make a pretty nice solar heater. Or perhaps run a sterling engine to generate electricity.

 

[smagzilla]

i was thinking that too. Theres a video of it on youtube. I seen an easy way to produce electricity was to hook it up to a battery drill motor to make 12 v. seemed pretty easy to do and cheap to make. also making a forge to melt stuff down looked cool.

 

[smagzilla]

i meant somehow hooking up a shaft from the steam engine to the drill motor chuck.

 

[IronWing]

Is there a list anywhere to find out the quality and actual existance of fresnel lenses in tv's based on make/model and size? that would be dope!

Not that I know of. All rear projection TVs should have a fresnel lens but some are linear instead of focusing to a single point.

 

[MrDudeMan]

Is there a list anywhere to find out the quality and actual existance of fresnel lenses in tv's based on make/model and size? that would be dope!

i don't understand why everyone is implying that these lenses are hard to find. i've purchased dozens of them over the years for DIY projectors. they're cheap and very easy to acquire.

example

 

[IronWing]

i don't understand why everyone is implying that these lenses are hard to find. i've purchased dozens of them over the years for DIY projectors. they're cheap and very easy to acquire.

example

For large lenses it's far cheaper to rip them out of old TV sets than to buy new. There is also the ethical aspect. When one rips the lens out of a TV set there is one less TV set in the world, a blessing on us all.

 

[Jaepheth]

I would like to eventually set up enough mirrors and fresnel lenses to do some backyard solar foundry casting work.

 

[smagzilla]

based on videos ive watched on youtube there are big differences in good lenses and not so great ones. I dont have a way to transport that big tv right now so if i new i scored a good one it would be worth acquiring said vehicle. yes i know they are free on craigslist normally.

 

[MongGrel]

Had an old Hitachi that probably had one in it, wish I'd stripped it out years ago for fun and games.

 

[Red Squirrel]

Speaking of TVs we got rid of 4 32" monster TVs at work, wish I would have opened them up to keep the circuit board and other goodies in there. Nice big capacitors too. 😀

 

[Ichinisan]

Aww. There was a Sony 4:3 projection HDTV by the dumpster at my apartment for a while. I waited too long before I thought about making a death ray. I was extremely ill with food poisoning when I thought about it, so I couldn't go salvage the fresnel. Now it's deep inside the dumpster. 🙁