out of focus Pentax Optio s55

[greynex]

I have a Pentax Optio s55. When taking photos of tall buildings on a trip to New York, even though I pressed the shutter halfway to focus, on inspection of the photos the tops of the buildings appear slightly out of focus.

Would I have done better using manual focusing?

[Rufford]

Sounds more like a depth of field problem to me. Try closing down the aperture more; you may have to use a tripod if you do this though. Most buildings are big, it's probably just that the tops are out of the focus plane.

Goodluck and welcome to the site.