Make sure you have your pointer over what you want to zoom in on. Quite often if you have your pointer over empty space it will zoom in "too fast" and "too far". Try that and see if it makes a difference. If not it could be a setting / graphic issue.

And welcome to the SCF.
http://www.manysmileys.com/files/R/Mb/sC/RMbsC28W33794092.gif