Until the 80's all the lens made by the manufactures had the same build quality, faster lens were just faster, more glass, few lens made, cost more. When I shot with Nikon my 28 2.8 was built as well as the 2.0. I shot most of the time with the 2.8 and only took the 2.0 for very low light. Even to day I have M42 Pentax glass, fast and standard, most the time I just take the standard glass. S o unless you plan on shooting in very low light I recommend starting with the standard lens and adding fast glass if you really need it. As mentioned by others consider having your gear cleaned and adjusted.
Originally Posted by pierods