The light emitted by the focus light may be viewed as ambient light. Therefore to eliminate the hot spot of the focus light, just increase your shutter speed. As long as you don't choose a speed that is quicker than your sync speed, there are no down sides. At night, the last thing you're interested in capturing is ambient light anyways because aside from the aforementioned focus light, there is none. For point and shoot digicams try 1/250 sec.
BTW, On night dives I use a mini q 40 (4AA) with a home made red gel filter (Roscolux #027) inserted between the bulb and the inside glass. The gel filters are paper thin, cut to shape with a pair of scissors, and do not adversely affect the water tightness of the focus light. Roscolux is carried by many theatrical supply houses and at online photographic retailers.
Many night critters are not as skittish when a red light is aimed at them as they are when a bright white light is. My Oly c4040 has no problem picking up a focus lock when the red gel light is used to aid in focus. I commonly use shutter speeds of 1/250 sec at night with the Oly. Most p&s cameras will still sync at that speed (and much faster speeds).
hth,
b
BTW, On night dives I use a mini q 40 (4AA) with a home made red gel filter (Roscolux #027) inserted between the bulb and the inside glass. The gel filters are paper thin, cut to shape with a pair of scissors, and do not adversely affect the water tightness of the focus light. Roscolux is carried by many theatrical supply houses and at online photographic retailers.
Many night critters are not as skittish when a red light is aimed at them as they are when a bright white light is. My Oly c4040 has no problem picking up a focus lock when the red gel light is used to aid in focus. I commonly use shutter speeds of 1/250 sec at night with the Oly. Most p&s cameras will still sync at that speed (and much faster speeds).
hth,
b