In the search for a focus solution, I am going to abandon the laser pointer light source in favor of an AF assist light from a proper flash unit.
Doing some research here and looked at a whole bunch of flashes, and some of the flash manuals have a range in which the AF illuminator/assist light is effective. The listed number is the max range listed in the official user manual (in meters and feet).
-580EX II, 10m/33ft
-SB24, 25, 26 had no range listed for the AF assist light.
-622 and 622 mark II, 6m
-866 and 866 mark II, 10m
Ten meters seems to be the benchmark. So far, the Canon 540EZ seems to be the winner, with a range of 15m. That’s more range then Canon’s current state of the art flash, the 580EX II.
I have a broken 380EX flash which has a range (for it’s AF assist light) as good as a 580ex, so it will be a good start.
Just bought a new 540EZ AF assist module from ebay for under $30 after shipping. Have to figure out the voltages I can apply to this unit, without burning it out.