Henry Laurens in his lessons on the Arab provinces at the end of the Ottoman period (they are in French) makes a difference between anti-judaism and anti-semitism, the first being more personal and not targeting converts, the second more institutional and continuing to target converts with obvious overlap in themes. Is this a difference which is commonly accepted and used in analyzing related actions?
In terms of medieval and early modern scholarship (the time period usually seen as the birth of anti-Semitism), the part about "targeting converts" is close to the mark.
Anti-Judaism refers to opposition to Jews based on religion and religious practices. Anti-Semitism is generally used more for Jewish as representing a biologized ethnicity, something inherited from one's ancestors regardless of one's own cultural orientation. So in 15th-16th century Spain, with the growing suspicion that Jewish conversos and their descendants are "crypto-Jews" working diabolically to return other conversos to Judaism, the idea of an "inherent/biological" Jewishness bleeds opposition to the religion into opposition to people.