Figure 1: An unexpected explosion of infrared on my dry erase board.
Is there such a thing as an infrared bomb? I’m hard pressed to explain the picture in figure 1, one of the first infrared photos I’ve taken with the SD14. I had just taken the shot in figure 2 (a photo of me looking like an infrared zombie) – and had gotten up to check the camera. Without touching the tripod, I snapped off another shot of the dry erase board that hangs on the wall behind the chair I had just vacated. The photo of figure 1 emerged as a result.
Figure 2: Infrared Zombie (me).
I cropped the photo, moving the cutout in order to center the plume, and brushing the faint white lines that always follow the edges of a crop. In the picture, a flash seemingly emerges from the tray at the bottom of the board. Improbably, there appears to be a swirling “smoke” plume arising from the point of impact! The room was dimly lit by only a single window, near twilight. Therefore, a mystery starts the exploration of “Doing infrared photography with an SD14″ (Sigma) camera. Note that the shots are somewhat out of focus. That’s a fault of the operator, not the equipment! Focusing IR shots is not as simple as visual light shots, and I’m still learning.
So, with a bit of the resulting fun already described, I’ll write about the setup procedure (at least the one I used) – to ready my gear for IR photography.
To start, on the SD14 it’s necessary to pull out the sensor filter. Figure 3 shows this part of the gig.
Figure 3: To do IR on the SD14, one simply removes the filter shown
Notice the ridge at the top of the filter (near the top of the body). A fingernail on that ridge, given just the slightest nudge, pops the filter loose.
In my case, I wanted to use older lenses with M42 mounts (without the lens coatings that may impact IR performance). So, I procured a Kipon lens adapter for matching Sigma SA cameras to M42 lens mounts. It is shown in Figure 4:
Figure 4: Kipon lens adapter for M42 lenses on Sigma cameras.
Figure 5: The included Kipon tool mounts and unmounts the adapter.
The included tool mounts and unmounts the adapter. One must remember to press the mount lock/unlock button on the SD14 before trying to remove the adapter! The camera sees *it* as a lens.
Figure 6: Since it’s an M42 screw-on lens, we’ll do just that!
Figure 7: Finally, we are IR ready. Oops ! Well, almost.
I needed to screw a 49mm IR filter onto the front of the old Fujinon lens. It’s a filter that blocks visible light, with a cutoff value of 720 nanometers. This is confusing for newcomers, because the term “IR filter” is used both ways (as a reference to a filter that blocks IR, and also as a reference to a filter that allows IR and blocks visible light). So, the filter that I removed from the SD14 was an IR blocker. The filter that I screwed onto the end of the Fujinon lens is an IR allower (blocks only visible light). Yeah – allower isn’t a word.
I needed to find the shutter release socket on the SD14, which accepts a 2.5mm stereo plug for a shutter release trip-and-hold control. It’s really just a switch that connects the barrel circuit to the tip circuit, so a homemade device is a possibility. The unit shown in figure 8 was $8.98 – and I’m pretty sure the individual parts would cost more than that!
Figure 8: The audio plug and remote (cable type) shutter trip and hold.
Why is the trip-and-hold control needed? It’s because IR photos often require long exposure times (30 seconds is not atypical). Some shots that I took last night were on the order of two minutes! By the way, what I refer to as trip-and-hold control is more likely called a shutter release control by retailers. Another handy thing to have would be a shutter timer with LED readout.
The Sigma SD14 is a product of Sigma Corporation. Sigma and Foveon are their trademarks. This author and site has no affiliation with Sigma.
A Storm Of Photons 