K100D and InfraRed

Basically, does anyone have experience with K100D and infrared filters? Does it work, and well (without crazy exposure times)?

Just want to know before I spent £30 odd on a R72 filter

This site covers IR with a K100D. You may have to up the ISO, but that shouldn't be a problem as IR film was/is grainy anyway. An R72 filter is a good investment (IMHO)

...and Tim the Ammonyte has got some lovely IR shots with his *istDS, which uses the same sensor as your K100D, so it should be fine. Some here: https://www.pentaxuser.com/forum/viewtopic.php?p=40153&highlight=#40153

Dan

Thank you, solved my query perfectly.
I remember searching the web before I bought the K100D, interested as to what it was like at IR and finding nothing, so now I know

Thanks Dan, the cheque is in the post.

This answers a question I had a few days ago. I have some letters to my grandfather when he was in a Japanese POW camp in China 60 years ago, the letters are fragile and the writing has faded and is unreadable. A friend suggested that one technique is to illuminate the letter with ultraviolet light and take a photograph using IR film. (I'm not sure how this works, because it would suggest that the UV causes the writing to emit IR.) Apparently it is a forensic technique.

So it means that if I get an R72 filter I will have the IR end of things sorted, and the next bit is to determine what UV source to use.

Richard

Standard fluorescence. The same phenomenon that causes yellow fluorescent jackets to absorb UV light from the sun, causing the atoms to jump to an excited energy level, and then drop back down, emitting visible light photons as they do so

Oh yes, I know about that. My experience of IR is through one of these:

http://www.edinst.com/pl.htm

A PL5, 50W CW at 10um. We used a brick as a beam stop, the place where the laser light hit the brick would glow orange. It would take a lot of UV and old writing paper to get that amount of IR , luckily it used He-N-CO2 mixture and a 3000V discharge to give the population inversion.

(Heh I had a Crocodile Dundee moment with that, someone was playing with a laser pointer and I said "you call that a laser, *this* is a laser...". Well, you had to be there to appreciate it...)

Richard

Just found this comparison of various Pentaxes sensitivity to IR.

Hmmm, I wonder how you get the IR filter off the sensor... I've got a chisel and a mallet.

Anyone had this done? Know how much it costs?

Dan

We could lobby this lot to start carrying Pentax stock (link at the bottom of the page)