[daft_biker]

Originally Posted by mike1187

.... I'll probably eventually pick up another set of tubes to use with this lens to get even closer while at the longer focal lengths.

Personally I'd likely go for a teleconvertor if I wanted to increase the magnification on a long lens.

Up to about 100mm extension tubes would be my first choice for increasing magnification (or reducing the minimum focus distance if you prefer). With 150mm or longer lenses I find extension tubes don't really do a lot - but a teleconvertor does!

That's if you can get a teleconvertor to fit your lens! However, if you have extension tubes already you could just fit one of them to the lens and then fit the teleconvertor between the extension tube and the body.

Say you had one of those 70-300mm lenses with a 1:2 "macro" function....stick a 2x behind it and you've got 600mm lens that will do 1:1