Firstly, apologies if this question has been answered elsewhere. I've been scanning the forums for days, but can't find exactly what I need.
I am trying to build a remote shutter release for my Nikon D700 and D800. I want to be able to control the shutter via my laptop. This should be the simplest project in the world, but I can't get it to work.
I'm using an optoisolator (4N25), connected as follows:
Pin 1 connects to the D13 pin of the Arduino
Pin 2 connects to a resistor, then to ground
Pins 4 and 5 connect to the ground and auto-focus contacts of the camera.
Initially I just want to make sure that I can auto-focus the camera (equivalent to half-press of the shutter release). When I make the D13 pin go HIGH, the resistance between pins 4 and 5 on the 4N25 drops to about 100 ohms. But that doesn't seem to be low enough to make the camera auto-focus. Many people have built a similar devices, but no one mentions this issue.
I'm sure the electronics side of things is correct. Could this be something specific to the D700/D800?
that the Nikon cable is different from the one in your picture. In any case, did you try to short circuit the focus and ground pins without any optoisolator?
I have an ongoing shutter release release project for my steampunk camera. Here is the previous version (current version adds a switch to control whether the buzzer is used): http://arduino.cc/forum/index.php/topic,117629.0.html
In your diagram, it looks like you are using a Pixel CL-DC0 or similar cable that has a 2.5mm phono adapter on one end and the Nikon specific bits on the other (I happen to use the CL-RM1 or CL-UC1 on my shutter releases, depending on which Olympus camera I am using). Here is a site that shows all of the various camera specific cables and where the shutter release buttons are: www.doc-diy.net :: camera remote release pinout list
I've read in other places that D13 has some special considerations due to having the builtin LED attached (builtin resistor). You might try a different pin.
Do you have a wired shutter release? Does it work to trigger the camera? On some cameras you might have to enable the shutter release via camera option.
You mention putting a resistor between the ground and pin 2. Is there a reason for this? On my 4n35, I don't put a resistor between ground and pin 2, since the spec sheet says that it can be triggered by 5v.
Assuming your camera is in the mode to trigger the shutter release, connect your cable to the camera, and create a short between the middle band and the band closest to the cable. See if the camera auto focuses. If not, perhaps the internal wires inside your cable are broken. I've had at least one shutter release stop working because the cable wires stop working.
Did you verify the 4N25 is working by putting a LED on it, with the LED on an independent circuit? I did this with my 4N35 that I used in my shutter release:
Thanks for the responses so far. Here are some points of clarification:
at this stage I just want to auto focus at this stage. If I can get that to work, then triggering will be straightforward.
the cable I'm using has a Nikon 10 pin connector on one end, and a 3.5mm jack on the other.
if I short the wires, the auto focus triggers. Which means that the cables are all good.
This is why I'm confused. Everything seems to be good. The only reason, that I can see, for the auto focus not triggering is that the resistance between pins 4 and 5 on the 4N25 only drops to 100 ohms. It doesn't drop to zero. I've tested this with four different 4N25's, and I get the same effect on each one. But surely I'm not the first person in the world who wants to trigger a D700 or D800 with an Arduino? I also want to trigger a Canon 5D Mk2. I wonder if anyone has any experience there?
My device is now working. The 4N25's have been replaced with reed relays. The image below shows the completed circuit. I will use this to fire two cameras simultaneously. The AF trigger is connected to Arduino pin D13, and the shutter trigger is connected to pin D12. The D13 pin is set to high momentarily before the D12 pin is set to high.
if I short the wires, the auto focus triggers. Which means that the cables are all good.
This is why I'm confused. Everything seems to be good. The only reason, that I can see, for the auto focus not triggering is that the resistance between pins 4 and 5 on the 4N25 only drops to 100 ohms. It doesn't drop to zero.
Did you see the coment from Michael about Arduino pin 13 being unsuitable because of the on-board LED and resistor which are connected to that pin? Did you try with a different pin?
MichaelMeissner:
Do you have a wired shutter release? Does it work to trigger the camera? On some cameras you might have to enable the shutter release via camera option.
For Nikon DSLR, wired shutter release is always enabled but IR shutter release (on the lower-end cameras) needs to be enabled.
Nantonos:
Did you see the comment from Michael about Arduino pin 13 being unsuitable because of the on-board LED and resistor which are connected to that pin? Did you try with a different pin?
I think the problem was with the 4N25's, not the D13 pin. But that said, it's good to note for future reference that the D13 may be unsuitable for certain applications. However, with the reed relays in place, there don't appear to be any problems now.
