Help! Not sure what happened here other than I know I have some sync issues. Background: Was shooting election night campaign party. The pictures here were shot back to back. The first had sync problems on left hand side of photo. Next image came out fine. No settings were changed on camera between shots. This same issue occurred on about half of the images i shot, four rolls worth. Shot with Canon F-1, 50mm 1.4, Sunpak 555 set on manual and occasionally automatic, shutter speed 60 (sync speed). I have no clue and was just wondering before bringing it to shop if any of you had experienced anything similiar.