Remote shutter (or 'cable release') is a feature on many SLRs and larger format cameras which allows the shutter to be triggered by means of a remote switch. This consists of a shutter release button in a hand-held remote, linked to the camera with a cord (or in the case of manual cameras, a wire encased in a flexible tube which physically activates the shutter). This is most often useful where the vibration caused by pressing the shutter button on the camera would affect the sharpness of the image, for example when using a long telephoto lens or when the camera is mounted on a lightweight tripod which is susceptable to vibration. Remote shutter operation is also useful when the camera is mounted in a position where access is difficult or impossible.

Wired remote switches are typically very simple devices, containing only a few switches and no electronic components. This, combined with the expense of brand-name commercial versions, makes them ideal DIY projects. Lower-end Canon SLRs, among others, use a standard 2.5mm stereo jack socket for the remote switch (a smaller version of the type commonly used in headphones), which makes interfacing with the camera easy. I believe the remote switch described below is an exact replacement of Canon's RS60-E3 remote, which is compatible with the following cameras:

• Canon EOS 300D, 350D, 400D, 30, 33, 50, 50E, 300V, 300, 500, 500N, 3000, 5000, IX and IX7
• Contax SLR 645, N1, NX and N digital
• Pentax *istD, *istDL, *istDs, *ist, *istDL2, MZ-6, ZX-L, MZ-L, K100D, K110D and K10D
• Samsung GX 1L, GX 1S and GX-10

The focus button acts like the shutter button on the camera pressed half-way, and the other two switches act like the shutter button on the camera pressed fully down. The alternative toggle switch for the shutter button is used for long bulb exposures, where the shutter is held open for as long as the button is pressed down. There is considerable flexibility in the type of switches that can be used: ideally, a two-stage switch such as that used in the camera body would be used, but these are somewhat more difficult to obtain than normal switches.

The longest 3.5mm to 2.5mm jack cord I could find was 1.5m. Much longer 3.5mm to 3.5mm jack cords are widely available though, which can be changed down to a 2.5mm plug on one end with a suitable (and also widely available) converter.