I have to admit, I knew about this, but I didn’t want to spoil the fun.

I’m a Canon guy, and I have been looking for a cheap 300/350D body for a couple months, so I could try this out. I was actually going to attempt to do the conversion myself. But I would have still needed to add an external IR filter. So what this guy is doing definitely takes it up a notch!

And $275 seems pretty reasonable, actually. So his site has been bookmarked…

Thanks for the tip!

That's fascinating.

Your dog is pretty darn cute too.

I actually use black and white film when shooting pics of my dog. He's a Dalmation mix and he looks great in black and white.

If you want to test your digital camera's sensitivity to IR, look at the LCD screen on the back while pointing a TV or DVD remote at the lens. When you press the remote buttons you'll see little flashes of "blue" light that are invisible to the naked eye. That's one of my favorite party tricks.

oh my god - did you hear that pajamas media blogger dan drezner killed himself this morning?

The filter over the CCD, isn’t that called the Low Pass Filter? So it filters out IR huh? Interesting.

Ignoring the ravings of the insane ...

Interesting bit of gear, Stephen. Long ago, I had fun with IR slide film, but its impossible to find and was difficult to process ( E-4 ) even when you could find it. I'll have to show you my slides of the Santa Barbara mission in IR sometime.

KZ,

Yes that filter is called a low pass filter.

But it doesn’t filter out IR. It’s just the opposite. It allows IR to pass thru. It blocks the higher frequencies.

Just remember, IR radiation occurs at a lower frequency than visible light, and UV (ultraviolet) occurs above the visible spectrum.

The rainbow we can see is ROYGBIV. Infra means below the R (IR), and Ultra means above the V (UV).

Jaymaster, thank you. But doesn't the camera's original Low Pass Filter (the one Stephen replaced) remove IR from the spectrum reaching the CCD? Or, does the newly installed filter block all but lower spectrum radiation?

BTW, the CCD (at least the way it’s set up in the stock camera configuration), like the human eye, only detects three wavelengths of color, red, green & blue. This is the additive color model of light itself, the opposite of pigments & paints that give us the subtractive model. The channel mixing in the brain is what allows us to see all those colors of the rainbow. Perceived yellow is, in fact, a mixture of red and green. Counterintuitive I know, but true.

KZ, no, the original filter was a high pass filter.

As to why this all happens, silicon isn't a direct bandgap semicondutor, so optical excitations are secondary scattering effects. There are other semiconductors that do much better and you really have to work hard to make silicon do optics even halfway decently. But with the electronics world paying the big bucks to get silicon working it's still worth it to do the extra work to get silicon optics functioning.

There does seem to be some confusion here, and I appreciate the responses to my postings. I’m intrigued by what Stephen has done to a perfectly good camera body.

The Nikon Manuel that came with my D70 says, on page 194, “The CCD image sensor that acts as the camera’s picture element is fitted with a low-pass filter to prevent moiré.”

I think my original assumptions were correct: the camera’s CCD comes standard with a low-pass filter that blocks infrared. How IR relates to a moiré pattern, or if it does at all, I have no idea. Still, this is a fun thread and a good learning experience.

Does this mean Steve's camera is now one of the "see-through-synthetic-swimsuit" cameras, only higher quality than the ones from before?

Steven, your dawg looks awfully like my Maremma Sheepdog.

What breed is he?

Good question, Mr. den Beste. I vote Mr. Green travel to the nearest location with appropriate test subjects (female, 21-30, wearing the garments in question), perform plenty of experiments, and submit the results for peer review.

Stephen, thank you. My old digital camera is now in pieces as my husband has decided to go ahead and try to modify it into an IR camera! He's just waiting to receive his new filter he ordered online. Here's hoping he can put it back together!

Does this mean Steve's camera is now one of the "see-through-synthetic-swimsuit" cameras, only higher quality than the ones from before?

[nod]