I'm planning on purchasing a focus light, and I'd like to feel confident I can control backscatter issues while using it. While hotspots can be avoided in most situations with small aperatures and fast shutter speeds, these techniques are ineffective against backscatter, aren't they? Particles are illuminated at any speed -- unless an "auto-off" focus light is employed. These are designed to shut off when they sense a strobe firing, eliminating hot spots and backscatter (unless the strobes themselves are improperly aimed).
But a camera's normal sequence of operation is 1) shutter release is depressed; 2) shutter is opened; 3) strobe fires for a fraction of the time the shutter is opened; 4) focus light turns off when it senses the strobe. If I'm correct, the focus light is on at step 2 and is unavoidably a part of the image lighting unless the strobe can be pre-fired before the exposure sequence begins.
Perhaps the solution is to turn on red-eye correction, which will pre-fire the strobe. That works for me but perhaps not for others using slave strobes triggered by the camera's strobe. Are there other solutions? Are my concerns well-founded?
