IR Converting a Kodak C1550 P&S

[Tim N]

So I have decided to convert a newer P&S camera and found a Kodak C1550 (16mp) on clearance for $28 at Target. I previously used a Sony DSC-P72 (3.2mp) and converted it without problems. I'm thinking this time I will replace the interior coated glass element with a cut 850nm IR filter glass. My only problem is the glass inside the Kodak is extremely thin and I'm wondering if replacing it with something a little thicker will cause problems. In an attempt to smooth off the red coating on the element, it actually broke into two pieces because it was so thin. I've since placed a negative cutting into the slot over the sensor, but it will not focus properly. Does anyone have a suggestion for how to compensate for this? The glass on the Sony was a lot thicker and also caused focusing issues when I tried it in the Kodak. I know the Kodak was cheap and this is what I was afraid of when I bought it. Hoping the glass on the filter I ordered isn't too thick, but I know it won't be as thin as the original one.

 

[Garbz]

I think you're out of luck. You can't simply replace the I/R cut filter with glass on a Point and Shoot. The I/R cut filter is actually bifringent which is how it also acts as an anti-aliasing filter. For a DSLR this doesn't matter too much because as the lens to sensor distance is quite large, but on a point and shoot the lens to sensor distance is tiny, so much so that a bigger piece of glass probably won't fit in behind the lens. This means that the light actually hits the low pass / aa filter at an angle and gets bent as a result. In P&S cameras the filter actually forms part of the focusing system.

Effectively you may now have an infrared macro lens, or in my last case similar to yours, a camera which can only focus when the lens was at max zoom.