AF Assist V2 (Update 19 May 2011)
Continuation of AF Assist v2 post.
The change o the op-amp did not do the trick as expected. In fact even though the NE5532 has a much quicker slew time, I didn’t make a difference. In fact I think it made things worse.
Two things I noticed about it’s function:
When the AF Assist tool is supposed to be off (ie. when on the camera but not activated by the camera) the laser LED is slightly on. Just barely, but enough to be noticeable on. There’s some leakage somewhere… and probably just drains the battery.
The other more pronounced effect the change in op-amp had was that the NE5532 had a brighter recorded image of the AF pattern (there really should be none) then the LM358. I took some photos with both op-amps at 1/10, 1/20, 1/40 and 1/80 to show the difference.
|NE5532 – 1/10||NE5532 – 1/20||NE5532 – 1/40||NE5532 – 1/80|
|LM358 – 1/10||LM358 – 1/20||LM358 – 1/40||LM358 – 1/80|
So there you have the comparison…
Maybe consider a MOSFET like i thought about before.
I think I may now know why the LED light is visible in the frame, after watching this explanation on how camera shutter sync works. The dot would likely all but dispensary around the camera’s highest flash sync speeds. What is happening (I think) is that the laser only turns off for the duration of the flash pulse (which is very brief). When the laser comes back online, the shutter is still open, and will record the light of the laser. I think what I need is something to delay the laser from back on for a little while.