sounds like your P850 might be defective.
mine focuses just fine, even in low light situations.
It may be the earlier models that suffer from this malfunction????
has a firmware upgrade been done yet?
out of ALL 6 Kodak cameras that I have owned and tested (CX6445, z740, DX7440, P850, v530, v550), the z740used had theWORST focus in low light. Maybe the unitI had was bad or defective, I dont know, but it was just horrible.