There are a number of resources out there for creating your own electronic remote shutter release for Pentax DSLRs with a 2.5mm remote port. I don’t use a remote very often as the 2 second self timer seems to work fine for 99% of my photos under 30 seconds. However, longer bulb exposures require a remote. So, I picked up a generic cellphone headset at the dollar store and wired it up to a toggle switch I had laying around. (It seems this design also works for Canon Digital Rebel cameras with 2.5mm remote ports.)

There are 3 wires inside one of these cables: white, red & black. (Four conductor versions will not work with a Pentax so make sure the 2.5mm plug has 2 silver bands and not 4). All I did was cut the cord, strip back the outer jacket to expose the 3 conductors then plugged it in to the remote port on the camera and shorted the red and white wires to the black one to figure out which controlled what function on the camera. In this case the white wire triggered the shutter and the red caused the camera to auto focus. I connected the white wire to one side of the toggle switch with a small acorn nut and the black to the other side. I drilled a couple of holes in an old pill bottle to make a housing for the assembly.

superior ergonomics of the pill bottle housing

In standard shooting mode flipping the switch to the “on” position releases the shutter. You have to return the switch to the “off” position to review the shot and take another (ie: the shutter only fires when the switch is in the “on” position). For bulb exposures you simply flip the switch to “on” to open the shutter then flip it back to “off” to close it. A momentary switch would facilitate non-bulb shutter releases but I found the toggle switch to be perfectly workable as long as you remember to turn it off after the shot. There’s no auto focus function with this set up but that’s not typically a concern for the long exposure shots I take as I usually manually focus anyway. You can add a momentary switch to the focus wire if that’s important to you. Also, you could wire in both a toggle switch and a momentary switch to the shutter release to make non-bulb shots more convenient.

1 minute bulb exposure using DIY remote release switch

Typically I have seen these DIY releases installed in an old film canister. Seeing as how I haven’t shot film in about 10 years I didn’t have one handy and figured the pill bottle was a good substitute. All was good with the use of my $1 release during my first outing until I was stopped and questioned by a policeman while shooting long exposures in downtown Auburn, AL. Seems he was less concerned with my skulking around in shadows taking pictures and just wanted to know what was in the pill bottle :D

UPDATE:

Shot the family Christmas card photo today and needed a little more reach than the original 12″ cord provided. 50′ of old speaker wire from the garage and a couple of extra wire nuts and voila!

DIY Pentax cable release with 50' cord.