Later lenses use a Bay (bayonet) 60 size. I'm not sure where the cut off is, but I also think the CT* is the 50. But measure the diameter of your lens filter mount, if it's approximately 60mm, you have the Bay 60. 50 or 60 are your only 2 possibilities, so we don't need precision here. If you measure the outside, you should get something a few MM greater than 50 or 60.

Regardless of Bay 50 or 60, +1 on the adapter. Though the original H'blad hoods are nice.