Legend has it that he departed because he and Stan Lee disagreed over the true identity of Spider-Man's nemesis, the Green Goblin. But Ditko, himself denied this, saying:
"Stan never knew what he was getting in my Spider-Man stories and covers until after [production manager] Sol Brodsky took the material from me ... so there couldn't have been any disagreement or agreement, no exchanges ... no problems between us concerning the Green Goblin or anything else from before issue #25 to my final issues."Ditko's successor on Spidey, artist John Romita said that Stan and Steve:
" ... ended up not being able to work together because they disagreed on almost everything, cultural, social, historically, everything, they disagreed on character."Stan Lee informed fans of the departure this way, in one of his Bullpen Bulletin items:
"Steve recently told us he was leaving for personal reasons. After all these years, we're sorry to see him go, and we wish the talented guy success with his future endeavors."What we do know, is that Ditko immediately started doing superhero work at Charlton after his departure from Marvel, illustrating the adventures of Blue Beetle, the Question and Captain Atom.
Here's a look at his Charlton covers from that period. These issues are collected in DC Comics' "Action Heroes Archives," published back in 2004.