K10D - Infrared performance?

I might be wrong, but I believe that if you take a color picture and try to get an IR effect, it is possible but it will not be the same than the real IR. If you use an IR filter you will get really some IR light and some near IR light.

I think it has to do with the dynamic range of the camera that cannot take all colors possible from very dark to very bright in all three color modes. In the same way it cannot take all the colors and all the IR light at the same time.

Also, I believe some things like trees have certain effects in IR that they don't have in normal light.

I am not a specialist, but I believe that there is a difference between a picture taken with and IR filter and a color picture modified in photoshop. Obviously in both cases you can produce stunning results.

A few links on IR photography:
http://www.wrotniak.net/photo/infrared/
http://www.cocam.co.uk/CoCamWS/Infrared/INFRARED.HTM
http://dpfwiw.com/ir.htm

The meter does work, but it's not totally accurate because it's not designed for this. So, bracketing is wise.

you are quite right of course, the photoshop fiddle where you kill the blue channel and boost red and green isn't really much to do with IR, it just produces results which LOOK a bit like IR shots.

CCD and CMOS sensors are actually very sensitive to IR radiation, bizzarly it is for this very reason that a lot of digicams aren't very good at IR photography. To stop the IR light messing up the visible colours completely the manufacturers put a filter on the sensor which cuts out most of the IR. By the time it hits the sensor the IR light is about 6-10 stops weaker than the visible, hence the special filter and really long exposures needed to do IR digitally.

There was an instance very recently of one class camera being released with an ineffective IR filter. It had the effect of causing many dark or black items to have a magenta colour cast . The company in question is offering a free "Upgrade" (correction) and (I think or was it OR) free IR blocking filters in the choice of thread sizes. It wasn't even a Canikon.

Sony camcorders with their "niteshot" capbility had very much reduced IR filtering, and many people have used them to take IR video. One has to be fairly careful about what clothes people are wearing, as some materials don't block IR too well.

The focusing point in visible light and infrared are different. This used to be marked on the lenses (in red), but most lenses do not even have a distance or DOF scale on them. How do you change the focus to ensure you have the right focal point, without these guides?

You estimate by focusing slightly closer, and use as small an aperture as possible.

It isn't a perfect scenario, but it does work. Some, particularly USA based, photographers have the IR filter removed and replaced by plain glass to make a customised IR camera. Apparently old 2MP Kodak cameras are unusually good for IR work.

Back to the subject of metering, with the DS (haven't had a chnace to try it with the K10D) I found the metering to be reasonably accurate, and after a while you could get a feel for how much compensation to use. But as John says - bracket! Or at least start from the exposure time suggested by the meter then try it at 2x and 3x times. Use the image replay and the histogram and you get a good idea of the final image. And with digital you aren't wasting film by experimenting, it's only electricity!

and here's another link worth looking at http://www.jr-worldwi.de/photo/index.html?ir_comparisons.html

I have had an initial try with the 10D and the results are not good. I have had some superb resilts from my D and was hoping for similar from the 10D but not so I,afraid. Back in the dark age I used to carry two camera bodies when out and about the Z1 with colour slide film and an old ME Super with black and white film loaded it was never a big hardship due to the small size and weight of the ME super. Now it looks as though my D will have to come as well as the 10D on any days out. Not that I'm unhappy with the 10D the results are superb particually the shake reduction but I did pick up the negleted D when I did the infra red test and I did still feel very good in my hand.

David Benson

Just read this on the Pentax Japan site:
That might explain the IR issues...
Matt

Now I remember why I am going to hang on to my DS!