JCam Loc: MD Eastern Shore

I purchased this telephoto lens from B&H shortly after they were introduced, about four years ago and have generally been satisfied with it although it does get soft at any extension beyond 250- 300mm. I mostly use it on the water for sailboat and speedboat races. There is frequently little time to fuss with settings between shots so I use a fixed shutter speed of 1/1000+ and an ISO high enough to get me that shutter speed. The camera is a Canon 60D and ith the crop sensor I get about a 60% increase in virtual mm length so at F/16 I have an effective +/- 480 mm focal length

Three Questions: 1. Does that 60 % increase factor hold for all distances or does it reduce when focusing on closer subjects?

2. My eyesight isn't as good as it was 50 years ago and on nice night with a decent moon I occasionally try a moon shot, but still with the AF because even at maximized enlargement the LED I can hardly tell the difference. I haven't been very satisfied with the results.

3. At long shooting distances, I have noticed that the AF stops at a point on the scale about 1/4" short of the infinity symbol(~) center; should it, or is the lens/camera calibration possibly out of adjustment?

Both of the attached samples have been cropped, I'd guess that the log canoes were about 4-500 yards away.