Questions about Triggering of Camera and Flash
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I'm just getting started in high-speed photography. What kinds of triggers do you recommend?
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Can I trigger my camera's electronic shutter with a photogate or other trigger?
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My flash doesn't have a PC cord. How do I connect it to the trigger?
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Can I trigger a Pocket Wizard or other wireless controller with a HiViz circuit?
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Do HiViz circuits output a voltage that can hurt my flash unit or camera?
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Can I use an AC to 9-V DC adapter to power a trigger circuit?
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My HiViz delay circuit won't trigger my camera shutter. What can I do?
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How do I get a trigger circuit to discharge a Nikon SB-600 flash?
A sound trigger, photogate, and delay unit cover many situations. The SPG1 style photogate provides for flexible positioning of the emitter and detector. You can also replace the infrared LED with a red laser pointer in order to operate the photogate over large distances. A delay unit is often used with a photogate. If, for example, you want to photograph splashes, you need to delay the discharge of the flash from when the drop passes through the photogate until it reaches the water's surface.
When using the sound trigger, delays are usually set according to the distance from the source of the sound to the microphone. Figure a delay of about a thousandth of a second per foot (30 cm) of distance. If you need particularly long delays, then it becomes convenient to use a delay unit. You can use the same delay unit as for the photogate.
The delay unit can also be used with a contact trigger. See this page about contact triggers. You would simply connect the two wires from the contact trigger to the input and the ground of the delay unit.
This is a useful thing to be able to do if you're, say, photographing insects, birds, or other unpredictable subjects. You simply can't hold the shutter open waiting for the subject to do its thing. Our triggers and delay unit will trigger either flash units or camera shutters that have electronic shutter cables. In order to do the latter, you'll need to cut your remote shutter cable in order to splice it to the trigger or delay unit output. The remote cables usually have 3 wires. Shorting 2 of them together performs the autofocus and exposure operations of the camera. Shorting the 3rd wire to the other two closes the shutter. You would use the output of the trigger or delay unit to perform the latter function.
Some cameras have shutter cables designed especially for DIY projects. An example is the Nikon MC-22 remote cord which works with the Nikon D series cameras with the exception of certain models (see below). The cable ends of the MC-22 are blue, black, and yellow. Shorting the blue and black ends together does the autofocusing and exposure operations. Shorting the yellow cable to the other two actuates the shutter.
Cameras with infrared remotes such as the Nikon D70/70s aren't well-adapted for use with our triggers. While you might be able to wire a trigger directly to the remote, the shutter lag may be unacceptable for high-speed applications. See this link for a discussion.
3. My flash doesn't have a PC cord. How do I connect it to the trigger?
Not a problem. Adapter shoes are available that have a PC cord. A photo and description are given here.
If you need a PC cord specifically for a Vivitar 283, search for Vivitar PC-1 on the website of your favorite photographic supplier. Some suppliers are listed in the answer to the next question.
4. Can I trigger a wireless controller such as a PocketWizard with a HiViz circuit?
Here's a comment from Scott Thorson: "I spent some time last night working with the flash triggers (sound and photogate) and my Pocket Wizard Plus II’s. I can definitively say that it works. Using the same flash outputs (1 & 2) from the circuits set up for Canon flashes, I can trigger the PW’s. I successfully triggered the PW’s from the “camera/flash” mini plug port (on the top near their antenna) as well as from their hot shoe (using a Paramount mini plug to female hot shoe adapter cable). This worked wonderfully and allows me to trigger several flashes and my camera as well, so I can take shorter exposures and not have to have the room totally dark to get the same effect."
5. I have an old flash unit that has high voltage across its terminals. Will this damage the HiViz trigger or delay circuits?
No. The trigger and delay circuits are designed to withstand 400 V across the outputs.
6. Do HiViz circuits output a voltage that can hurt my flash unit or camera?
No. The output stage of the trigger and delay circuits is simply a short circuit. The latter is what is required to trigger most flash units.
7. I'm using a flash unit that requires a voltage pulse of 5 - 10 V to trigger. Can I use a HiViz trigger or delay circuit for this?
Yes, with modification. Connect a voltage source of 5-10 V in series with the output of the trigger or delay circuit and your flash unit. After each triggering, you may need to open the output circuit and then close it again in order to effect a reset. The diagram below shows the connections for a 9-V trigger pulse.
8. Can I use an AC to 9-V DC adapter to power a trigger circuit?
This works fine. Use an adapter with a 9-V DC output at up to an ampere of current.
9. When using a HiViz delay circuit to trigger my Canon 430ex or 580ex flash, the flash unit is disabled after each discharge until I turn the unit off and on again. What can I do?
Versions of our kits prior to v10 used the 22-kΩ resistors shown in this photo. If this is what you're using, try replacing the 22-kΩ resistors with 1-kΩ resistors. Or try this method reported by Brad Steel: Connect a 4.7k resistor in between the delay SCR output and the flash wire. We think this has the effect of limiting residual current in the Canon trigger circuit that would otherwise keep the SCR closed.
10. When using a HiViz delay circuit to trigger my camera shutter, the camera is disabled after each discharge until I turn the camera off and on again. What can I do?
Try the fix given in the previous Q&A.
11. My HiViz delay circuit won't trigger my camera shutter. What can I do?
Try replacing the 1-kilohm resistor with the larger 100-kilohm resistor provided with the kit. This will hold the trigger output signal high for a much longer period of time. Some camera shutters require a longer output signal. (This tip comes from Oleg March.)
12. How do I get a trigger circuit to discharge a Nikon SB-600 flash?
First put the SB-600 in manual mode. Then you'll need a way to attach the SB-600 to the trigger circuit output. See the following link for a way to do that.
http://strobist.blogspot.com/2007/12/easy-nikon-sb-600-sync-jack-mod.html
Thanks to Tom Denham for the information above.
13. When I use a trigger circuit to actuate the shutter on my camera, the image doesn't display in the LCD until I disconnect the trigger circuit. What can I do?
This happens because the output of the trigger circuit latches closed until it's reset. Try connecting a normally-closed pushbutton (available from Radio Shack) in one of the wires that you connect to your camera shutter. After each shot, push the button momentarily to reset the circuit. This should also allow the LCD to display.