Actually I had the same problem with a Canon PowerShot A60 and although I had this line: SYSFS{idVendor}=="04a9", SYSFS{idProduct}=="3074", MODE="0660", GROUP="plugdev"
It only worked when changing the permission to: MODE="0666"
I hope this works for someone else that came here looking for a solution and encountered the same problem as me.
Actually I had the same problem with a Canon PowerShot A60 and although I had this line: SYSFS{idVendor} =="04a9" , SYSFS{idProduct }=="3074" , MODE="0660", GROUP="plugdev"
It only worked when changing the permission to: MODE="0666"
I hope this works for someone else that came here looking for a solution and encountered the same problem as me.