IR Mode x Focus on DS-2CD2632F-IS

[lingnau]

We have a brand new DS-2CD2632F-IS that we just installed. From what I can judge it is properly focused. But during the night when it uses its IR leds, from what I can tell the images gets blurry. Is that normal? Has anyone experienced this and does have any tips? Those are the full resolution images from our DVR. (From left to right: Daylight, night and dawn)

Btw: It was quite difficult to get the focus right. Those levers are sensitive.