Function in View

On 9.2.0.8 database, I have a view that another DBA developed with one of our developers that contains a function.  This function has some selects that hit the same table as the view uses, which has 150,000 rows.  When I select data through the view, it takes a long time and calls the function for every row in the table.  When I select using the sql of the view directly to the table, it runs in < 1 second and pulls the same rows, only calling the function for the filtered rows, and returned amount of rows is around 300.  Is it normal operation of