Step Up/Down rings and couplers

[Shakespeare]

I want to connect my 70-200 f/4 (67mm threads) to the 50mm (52mm threads). There's no direct macro coupler that will connect the two. Can Step Up or Step Down rings help me in a similar way? If not, how do I get these two lenses together?

S

[sid]

I think your best bet might be to use a step down ring 67mm to say 58mm and then use a 58-55mm coupler.

[jyrgen]

Yes, rings will do, any combinations that have 52mm male thread in one end, some coupler somewhere, and 67mm male thread in other end. Some examples: 52-52 coupler plus 67-52 step-down ring, 52-67 step-up ring plus 67-67 macro coupler, 52-58 step-up ring plus 58-58 coupler plus 67-58 step-down ring, 52-77 step-up ring plus 77-77 coupler plus 67-77 step-up ring. You can also glue 52mm and 67mm cokin adapters together.

[Shakespeare]

Thanks, guys. I think I've got my mind around it. I've already got a 52-58 coupler, so I'll do what sid suggests. Thanks!

S