Quote - Very true Simon also bear in mind that these work better on leses above 35mm..  This fact is why the 25mm extension tube won't work with anything shorter than a 35mm lens because the focus zone is moved in so close the front glass element on the lens prevents you from getting that close.

Good point I had forgotten about that, I have onlt ever used then on the 100mm macro, I could use them on the 50mm to get 1:1 but that would be pretty pointless as I have a dedicated lens that can do that.

 

I have not used a reversing ring for many moons lol, they are a good and cheap option.

 

Now if you are willing to play a little (just for the sake of it) you could try this:

 

I have a length of drain pipe about the same diameter as the lens mount; attached to this at either end is a Canon AF T2 mount one attaches to the camera and one to a lens. As long as the mounts are light fast, this gives you a very long extension tube. Focusing is not easy there is no TTL metering and no aperture control, the result is super macro when you get it all right! Focusing must be done by moving the subject.

 

They wouldn’t have made the cane if you weren’t meant to break the rules