Artist: Saihate no Majo (最果ての魔女) - http://www.pixiv.net/member.php?id=243649
The artist's first series. Three magical girls are brainwashed into minions for a powerful being simply known as "Eye." Has really cool camera angles in a few spots. 1-48 are the original version, 49 and on is a second conveyor belt version that has a bit more energy to it.