Build in strobe mode and external strobes

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Postby Alcadhrim » Wed Sep 29, 2010 12:54 am

So with the Nikon D60 the build in flash has two possibilities: I TTL or manual.
Now first, let's guess I want one strobe (connected by optical fibers on S ans S housing) in manual and the other one in TTL, is it possible? (Strobes YS 110 a)

Second: when I want to shoot in manual, with my two strobes, I suppose that the build in mode is not important (I'm of course in slave mode)?

Third what happened if the strobe is set on TTL and the build in in Manual

In fact my nikon dealer has not been sure at all. (He did not know there is actually a manual mode for the build in flash).

I wonder all that because of some unpredictable results mainly in manual mode.
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Postby bvanant » Sun Jan 09, 2011 7:16 pm

If you want to shoot TTL of any flavor, both the camera flash and the external strobe need to be in TTL mode. What fundamentally happens in TTL mode when the camera is not in the housing, is that the camera strobe sends out a test pulse and the camera sensor sees how much light comes back to the sensor. Then the camera sends out the correct amount of light (if it can) to illuminate the scene as you have set up the exposure (+/- exposure control). In the housing what happens is that your camera strobe sends a pulse of light through the fiber optic cable to the strobe which sends out a test pulse which the sensor measures and then adjusts the power. The camera then sends out a real pulse which goes through the fiber optic to the strobe and the power of that flash tells the strobe how long to fire for. If the camera flash is in manual (say at very low power like 1/128) to save battery and the external strobe is in TTL mode and expects a pre-flash that the camera doesn't send, all bets are off. If you shoot in full manual mode then it makes sense to turn off the pre-flash mode of the strobe and shoot the camera flash at very low power to save battery and make the recycle time faster. If you want TTL both the camera and the strobe need to be in TTL mode.

Hope this helps
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