Going Ga-Ga Over Infraread

Yesterday, my Pentax pal dropped me a text message that he had a Pentax ist DL2 that had been converted for infrared (IR) photography available. Decision time, so without hesitation I immediately jumped on the offer.


Pentax *ist DL2 with the DA 14mm f/2.8

The *ist DL2 was the last iteration of the Pentax *ist series DSLRs and was introduced just a few months before the K100D. Pretty much identical in specification to the K100D with the exception of in-camera Shake Reduction and fewer AF focusing points.



The *ist like the K100D series uses the excellent 6.1 megapixel CCD sensor. It's favored for IR because the sensor is particularly receptive which allows exposure times to be relatively short. On an IR modified camera, the camera simply has it's sensor's low pass filter removed. In it's place a very thin infra-red filter is installed. In this case wavelengths lower than 720 μm are filtered out.



Well you may be asking what's the practical benefits of having a IR modified camera as opposed to a conventional DSLR with a R72 IR or equivalent filter mounted? Basically there two. Firstly, as there is no IR filter in front of the mounted lens, the view in the viewfinder is clear, just like a normal DSLR. This greatly speeds up the process of picture taking.



The second obvious advantage is in exposure times. The IR filter mounted at the sensor is much thinner than a conventional screw-in filter. This allows exposure times to be reduced well within the limits of hand holdability. Roughly speaking, depending on the subject, exposure is typically between +0.7 to +2.0 EV over what the camera's TTL meter suggests. The shorter exposure opens up a wider realm of picture taking opportunities.



Shooting people is always a challenge because of the exposure times but the examples of a wedding couple that I shot show the capabilities of a modded camera. Skin tones take on a ghostly shade of white, but after all that's the fun of shooting IR. Lens used was the FA 28-200mm zoom.



With newer DSLRs with larger megapixel count being introduced, the generation of 6.1 megapixel cameras of the *ist and K100D series now seem to be overshadowed. The option to convert these cameras to be dedicated IR only cameras is an option I would recommend for those of use contemplating buying the newer crop of DSLRs. IR photography is fun, and a converted camera definitely brings the fun back.