UV camera project build question

Blinkie wrote:

Wow thank you everyone for your advice. There is a lot I need to understand. The reason I thought about this project was seeing a converted camera for sale on ebay. It wasn't a lot of money and the seller explains that converting the cameras was a hobby of theirs. I thought it might be fun to try myself. The seller doesn't explain the sort of filter he incorporates into the cameras. Apart from giving the nm figure. Have a look for yourselves at an old listing.

https://www.ebay.co.uk/itm/Canon-PowerShot-A480-Infrared-Converted-IR-670nm-Digital-Camera-Custom-Firmware-/352465874416?nordt=true&orig_cvip=true&rt=nc&_trksid=p2047675.m43663.l10137

The seller doesn't have anything currently for sale but but every now and then will list a similar item.

B

Compact cameras are often very easy to convert, I've even done one myself (though I need to revisit it to improve the focus range).

The nm figure quoted for filters is roughly the point where 50% is transmitted. Unless stated otherwise it will be a long pass filter, which effectively only transmits above the listed cut off. In most cases long pass filters will have a rapid transition, only small traces will be seen below the quoted nm but there are a few filters that have much more gradual changes.

670nm (as your example) is in the deep red so will give NIR with a trace of the visible red. You won't see any UV with that conversion. (Visible is roughly 400-700nm, UV is below 400 & NIR above 700)

Some sellers use 'full spectrum' for conversions where glass or a UV filter has been used instead of the hot mirror. IMO these should be called 'two spectrum' as UV is reduced well below the sensors native sensitivity.

At least compact cameras have small lenses, so the glass in them will not absorb too much UV. If the lens coatings don't block UV they should be a fairly good option.