What is the proper procedure for attaching or removing extension tubes?
If you use extension tubes or extenders with your Hasselblad, it is of the utmost importance that you follow the proper procedure when attaching and removing them from your camera to prevent the camera from jamming. When attaching an extension tube or extender, always attach the tube or extender to the body first, and then attach the lens to the tube or extender. If using more than one tube, attach the first tube to the camera, then attach the second tube, and then attach the lens. When removing the components, it is essential that you remove them in exactly the opposite way you attached them. First, remove the lens. Then remove the tube or the extender from the body. If you are using more than one tube, remove the lens first, then remove the tube that is next to the lens, then remove the tube that is attached to the body. NEVER REMOVE THE TUBE(S) OR EXTENDER AND THE LENS TOGETHER! If you mistakenly try to remove the lens and tube(s) or extender at the same time and they jam on the cam
