Wobbly 180mm C

My 180mm C lens is really wobbly. The flared bit on the end is screwed tight

but it moves around the aparture/shutter speed rings. It still seems to perform

ok but I wondering if this is normal? My other lenses don't do this.

Sounds like the retaining ring is loose. You should take the lens in for repairs.

Take a look at the back of the lens, you'll notice in the center is a black ring with 2 slots in teh sides for a spanner. That is the retaining ring and may be loose. You can tighten it yourself but if it's loose it may be telling you that this lens can use some professional care.

Thanks guys. I'll take it in for someone to look at next time I'm down in London.