Day/Night Auto Refocus Issues...

John had mentioned a really nice feature that can often be found on cameras with true day/night cutover and remote auto-focus. He had also mentioned that out of focus images were also reported sometimes when using this feature.

Here's a possible scenario that could account for this, if and when using a camera with integrated IIR:

During the day, the camera is in DAY/COLOR mode and the IR CUT is ON and the IIR LED's are OFF. Camera is in sharp focus.

At dusk let's say the camera decides to switch to NIGHT/B&W and turn IR CUT OFF and turn the IIR ON.

The camera now refocuses by changing the focal length until the sharpest picture can be achieved. At this moment however, there could be considerable ambient light still reaching the imager. Because of this the camera may not be able to acheive perfect focus.

In addition, when later even if most or all ambient light disappears, the focus will not be re-adjusted, even though a clearer focus is now attainable due to the lack of shorter wavelength light.

Is this theoretically right at least?

Some cameras can store a color and bw focus position. Thus you could log on at night and focus, storing the correct position with no ambient light.