Lighting Tip: Neuter Your SC-17
Keep reading for he how and the why.
The SC-17 is basically an extension cord for your hot shoe that carries all of the various TTL connections. A flash, connected to your TTL-enabled Nikon via an SC-17 cord, may as well be connected to your hot shoe as far as the signals are concerned.
But the fact that it is off camera allows you to get better light, of course. I have written about this earlier, when talking about the strobe on a rope technique.
No longer manufactured, the SC-17 cords have since been replaced by the new (longer) SC-28, and the more expensive SC-29, which includes an AF-assist light. I like the SC-17 because you can find them on eBay pretty cheaply now.
You can link up to three SC-17s and still retain all of the TTL functions. Or if you are handy, you can splice a CAT-5 wire in there and run it about 50 feet, still keeping TTL.
But TTL is usually not what I use it for. In fact, I am trying to kill the TTL stuff for a specific reason. When shooting both with my Canon G9 and with the Nikon D70s, the trick to getting high sync speeds is to fool the camera into thinking there is no TTL flash connected.
If the camera senses a TTL flash, it will lock the sync at a max of 1/500th of a sec. Which is not what we want. So, we want a dumb, hot-shot-based sync cord to fool the camera into thinking there is not a fancy, TTL flash attached.
To do this, we will unscrew the little screws at the camera mount end of the cord and snip a few wires. It's easy, really, so don't worry about having to be a surgeon or an electronics wiz.
When you open the case at the camera and, you'll see five wires. The two wires you want to SAVE are:
1. The wire that connects to the big center post in the bottom, and
2. The wire that connects to the fail on the side.
These two wires constitute a "dumb" sync circuit. These are the two you DO NOT want to snip. The other three wires carry TTL info. Snip them and the TTL connection goes away. This also makes the SC-17 into a very good little hot-shoe-based sync cord for any brand of a camera with a hot shoe. No proprietary Nikon circuitry to worry about, either.
And for ultra-high sync stuff, this is better than using a Pocket WIzard. Because the electronics in the PW actually self-limit your sync to about 1/1000th of a sec. Not so a dumbed-down SC-17 (or a straight PC cord, for that matter.)
Some have correctly pointed out that an un-neutered SC-17 will work just fine as a dumb sync cord on a Canon. Bu I prefer to knock out those TTL circuits all the same, just in case there is some weird crosstalk going on that might harm the camera. Also, I use the cord for the Nikon D70s for the same reason. So it needs to be snipped for that reason, too.
If you do not want to ship your cord, you can always tape off the contacts at either the camera or flash connection point. But the cords are so cheap I prefer to just keep a snipped one along with my straight ones.
For multi-light setups, I will cord one hi-speed-sync flash and slave the others for multiple light setups in hi-sync situations.
Another thing: If you keep several SC-17s in your bag, you can chain the TTL ones together for a full TTL cord. But if you introduce one neutered cord into the chain, the whole chain goes non-TTL.
So, I keep three SC-17s in my kit -- two smart and the other one neutered. This gets me the best of both worlds when I am cording an off-camera flash.
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