We test the Pentax K100D digital camera for its suitability for infrared photography.
1/8 second at f3.5 and 200ISO
2 seconds at f16 and 200ISO
What we found when we put a Hoya R72 filter on the camera was that the new Pentax K100D has a fairly weak infrared blocking filter. So exposure times are not so very long as many recent digital cameras have.
Here is the image straight from the camera without a custom white balance:
This exposure was 0.3 second at f8 and 200ISO
The histogram (PS CS3):
And the individual color channels:
Red:
Green:
Blue:
Image noise
200ISO – 0.3 sec f8
400ISO 1/8 sec f8
800ISO 1/10 sec f8
1600ISO 1/30 sec f8
3200ISO 1/60 sec f8
So the Pentax K100D is quite a capable infrared camera unconverted, just the exposures are out of the handheld range except at wide apertures and higher ISO settings. But at least the exposures are not so long that you have issues with common moving objects.
So if you have a Pentax K100D, go ahead and get a Hoya R72 filter or similar and go get some shooting done.
Very helpful. I did the digital IR remote test and that gave me hope for using my Pentax K-100D for digital IR photography. Have done lots of generic reading on digital IR photography, which mostly talks about Cannon and Olympus and some Sony cameras. No mention of Pentax at all … that made me a bit nervous. Today, I decided to google for Pentax specific info and I was so glad that I found your page with photos, settings, and the recommendation … “So if you have a Pentax K100D, go ahead and get a Hoya R72 filter or similar and go get some shooting done.” I will! Thank you for your time, photo expamples w/settings info. Much appreciated!!
I too have had very successful results with a Pentax K100D. I generally us a 24mm lens ant f11, ISO 200 and a one second exposure in sunny conditions. Ive just bought a Pentax K-x and that’s nowhere near as good for IR as it appears to have a much more efficient inbuilt IR blocking filter leading to longer exposures and hence more noise.