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I need to make a camera lens that can easily withstand temperatures of about 1000 Fahrenheit.

What should I make the lens out of?

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Question that you may not have thought of: what band do you hope to image under these conditions? Remember that is elements will radiate a rough blackbody spectrum according to their temperature. Or do you desire that the camera be able to operate for short time in a hot environment rather than operating when the device itself is so hot? –  dmckee Dec 6 '11 at 3:04
    
Also remember that as your device heats up the lens will expand and flex which will screw up the focus. –  BebopButUnsteady Dec 6 '11 at 5:03
    
What is Your idea of "lens"? English language does not distict lenses per se and lens systems. –  Georg Dec 6 '11 at 11:43
    
@Georg: are you imagining a case where it would be useful for a "distinct lens per se" to be able to withstand high temperatures while the whole lens system could not? –  mattdm Dec 7 '11 at 18:29
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2 Answers 2

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Fused silica should be ok at this temp. Sapphire will also be fine. It seems unlikely that the correct design is to have your lenses at this temperature though, can you share more about your problem?

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(+1) Sure. I'm trying to get a clear picture from within my fireplace (I lost a bet). I know my fireplace doesn't reach 1000 F, however I'd like to be well on the safe side plus, the materials we use to start the fire can reach 3000 C, but because I doubt the spark would hit the lens head on... I use something like this to start my fire. –  wizlog Dec 6 '11 at 4:24
    
Is sapphire optically isotrop? –  Georg Dec 6 '11 at 11:40
    
Not a clue... Would I be able to use something like Borosilicate glass? –  wizlog Dec 6 '11 at 17:40
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Anything which has an index of refraction greater than that of the surrounding material (air, I suppose) can be used to make a lens. You have to adjust the shape of the lens to accomodate the index of refraction of whatever material you use, but there are known formulas for doing that.

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Is there an online calculator with explanations online? (I'm taking AP physics B, we haven't gotten up to that part yet). –  wizlog Dec 6 '11 at 4:24
    
Probably. Try searching for it. Or you can create a new question to ask for the formulas if you want. –  David Z Dec 6 '11 at 4:27
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Some tranparency might be valuable too. –  Georg Dec 6 '11 at 11:41
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