For long exposures some kind of cable release is essential. Sony Nex cameras don’t have any cable release connector but there is IR remote shutter control on most of the bodies except Nex 3 line. Infrared intervalometer doesn’t exist so the only grab and go solution is GentLED. Expensive and difficult to use (change exposure by trial and error, fixed intervals…). But it works. Recently I found out that it’s possible to combine digital intervalometer (simple unit from eBay worth 10eur) and IR remote control by soldering wires on the button contacts making IR intervalometer. Cool.
Some other people have more straight forward approach soldering three wires on the shutter release button contacts inside the camera and than gluing some connector on top of the body and using ordinary cable release or intervalometer. Than you can use common 2.5mm stereo jack.
One contact is ground (at leased 3 legs are ground) and one corner is “focus” and other corner is “expose”.
I found soldering anything but ground next to impossible (shutter release button is about 5mm long) so on my first moded Nex 5 I teared off the button and soldered coil wires on remaining contacts. Jack 3.5mm is located on the right side where used to be neck strap connected. Works fine, IR is still working too (good for sample images…). Now I received some “broken” Nex C3 cameras and after putting them together I decided to try it for AP. There is quite good sensor after all. C3 has no IR receiver. Soldering wires into the camera is the only option.
By accident I noticed four contacts next to the shutter release button with same function as shutter release button. I can see them on nex 5 also, in different place and Ground isn’t directly plugged to the button but I believe that it might work too. Check out the picture below. Three coil wires soldered to those contacts and wires are going out from the body through the flash hole. Wires can be identified by trial and error (shortage of Ground+focus forces camera to focus, for exposure all three wires must be shorted). I’m using coil wire as it’s high quality copper, perfectly insulated yet very thin. The end of this wire must be brushed with sand paper or file.
Update: It works fine, same contacts can be found on Sony Nex 3 and Nex 5, unfortunately Nex 5N doesn’t have these four contacts thus soldering directly to the shutter release button is the only option known to me. This time I managed without removing the button. It’s possible to lift up the button a little bit (I put M3 nut under) to increase accessibility of contacts and I lifted up corners of metal cover on the button (it is ground) to prevent shortage. Soldering was dreadful but successful at the end.
At least Nex 5N has some space between battery compartment and shutter (all the way down from AF beam), deep enough for stereo jack 3.5mm. If the connector is small it might go through the hole instead AF illuminator or somewhere lower between bayonet mount and grip (now hole needed). At this stage I just duck tape the connector somewhere to the camera.
Sony offers External power source consisting of dummy battery (DC coupler, fits instead of FW50 battery) with cable (female 5.5mm connector) and 240V mains adapter (AC-PW20) that delivers 7.6V 2A and is equipped with short cable and 5.5 male plug. I have 12V lead battery only (delivers 13V when charged). Hmm.
I made some measurements on my own and original battery when fully charged gives 8.3V, while “-” and “c” gives stable 2.9V (for charging internal battery MS614SE, 3.1V rated voltage).
Simply delivering 8V to the battery contacts isn’t enough, camera needs also 2.9V. Honestly I didn’t try to power the camera with 8V only. Not yet. On eBay are adapters without mains converter available for reasonable price. I bought some and there is indeed a tiny PCB inside that acts as voltage regulator converting inlet to 2.9V and leaving unchanged the power for camera itself. At the same time I got some voltage regulators (MP1584 Mini 3A DC-DC 1.5-26V Buck Adjustable Converter Step Down Power Supply). It’s small enough to fit inside the dummy battery, I just drilled off screw thread to make more space for this tiny PCB. The box has some locks on sides that can hold it together without screw and for better connectivity its a good idea to wrap the adapter with some tape – when contact is weak the camera complains “use original battery”. With connected voltmeter I adjusted the regulator to deliver 8V. It’s extremely important to solder positive and negative wires correctly as wrong polarity burns voltage regulator instantly (with cloud of smoke). RED on a battery is “+”.
When I plug in 13V battery (charged lead -acid/gel battery) Sony Nex camera claims 90% battery. That’s IMHO perfect as there is small margin for over-voltage and plenty of space for power drop during the night.
I didn’t try it yet in the field but expectations are high.
Next step will be permanent installation of external power supply together with cable release connector. I want all cables to leave the camera in same direction from same place. One possibility is to drill holes in the grip or integrate two connectors into DC coupler and glue it in place. Plastic case of the coupler does not have to be inside at all, contacts can be soldered directly to flex cable leaving even more space.