Return on that old thread :

I extracted from the high resolution scan that was provided two details :

One letter of the message that the camera was focused on (at 10-15 feet, for me - continental european - easier : 3-4m)

The sea horizon line (at random near the middle) of the picture (at infinity, indeed)

The discussion was about : while the picture was taken at D = 22 (with a 75mm lens), shouldn't the horizon line be sharper ?

The well known hyperfocal formula for a confusion circle c is :

h = f/Dc

So, when focusing at distance h, the blurring of details at infinity should be :

c = f/Dh

and taking f=75mm , D=22 and h = 3.5m you get a confusion circle of (approximately) 0.1mm

I put a white blob of this diameter in the middle of the horizon line, and you can notice that the blurring is of similar magnitude.

So to my opinion, the camera has absolutely no focusing problem, it's only an issue of DOF.

Paul