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Registered Member #119
Joined: Fri Feb 10 2006, 06:26AM
Location: USA
Posts: 114
My two favorite photos so far is the pile of tesla coils and the IR photo of the Lego transmitter. I like how you can sort of see through it and it has a picture next to it for comparison. I have some IR lasers that are 1064nm I think. Could they be seen with an IR camera or is it not in the IR spectra that these see?
Registered Member #15
Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
Silicon based sensors are usually sensitive to about 1100nm, however, this would be if the sensor was by itself. With most digital cameras, there is an internal IR filter which has a pretty steep cut-off around 700nm, so its pretty doubtful you'd be able to pick-up your IR laser using a stock digital camera.
Registered Member #56
Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445
It depends, 1064 at high enough power will usually look purple on a digital camera. 808nm looks red on mine.
I don't have too many ir shots, but I had a camera that was both ir/visible (ie, no filter) that had a bunch of ir leds around it. It seemed to control the led's by looking at how much light was coming in, so in bright conditions stuff looked normal (well at least as normal as things look in b/w) and in the dark things were different. One time it started oscillating and stuff was changing colors Unfortunantly the lens broke, so unless I can find a new one (that fits the tiny mount) or build a pinhole lens for it it will continue sitting in the hole it is in... I have shifted my interests towards my little pulnix ones that you can set the exposure down to like 1/1000s and have an external trigger for looking at fast things; but the only lenses I have are a really high magnification and the only output it is a composite video so I need to get my capture card working before I can get any shots out
Here is the only pic that comes to mind, not all the impressive yet, unless you know what it is and have been trying to get it working for like 2.5 years
Registered Member #15
Joined: Thu Feb 02 2006, 01:11PM
Location:
Posts: 3068
High power, probably. But most IR filters in digital cameras have a sharp cut-off around 700nm where near IR begins. Anything beyond that has considerably less transmissibility, unless of course until your remove the internal filter.
Here are two response curves of the infrared filters used in the Canon and the Nikon DSLRs. Canon uses the same filter material for most of its digital cameras, including handheld point and shoots, so i expect the response to be similar for a wide range of cameras.
Registered Member #79
Joined: Thu Feb 09 2006, 11:35AM
Location: Arkansas
Posts: 673
Well, I was going to post a picture of my camera, but I obviously can't do that. It has some IR looking LED's above the lens... I know my camcorder has IR for sure, it can see in the dark and has a built in 1.2Mp ha,ha camera. Could I use that?
What is something I could use around the house for an reverse-IR filter? A floppy disk? What about a CD-RW? Welding goggles? The thing that covers the IR reciever in a VCR?
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Unfortunantly the lens broke, so unless I can find a new one (that fits the tiny mount) or build a pinhole lens for it it will continue sitting in the hole it is in... I have shifted my interests towards my little pulnix ones that you can set the exposure down to like 1/1000s and have an external trigger for looking at fast things; but the only lenses I have are a really high magnification and the only output it is a composite video so I need to get my capture card working before I can get any shots out 
