Old adaptal II Tamron sp 90mm f2.5 - can be had for about £90 on ebay and has a great focus.
You can get an extender for it too fr about £20.
I shot all close ups of the leads plus the macro bug shots in this promo a while back with one
If you have a bit more to spend you can't go wrong with the Contax Zeiss 60mm f2.8 macro with a Canon adapter on it. Or the Leica R one is amazing too.
Shot the macros on this with the Leica one and the FS7
Adaptall was Tamron's prioprietary system of interchangeable mounts, so the adaptation to EF or E mount depends on what Adaptall mount you get with it. I always used Adaptall for Nikon F and then Nikon F to EF adapter. Speaking of the Tamron 90mm f/2.5, it is a fantastic lens, very sharp, with exceptionally good "round" rendering of the out of focus areas (bokeh). It is also very well built and focus is super smooth but it has one big weakness. The rear element is very flat and because of that the lens causes very strong internal reflections of the sensor (a type of an internal kick-back happening between the rear element and the surface of the sensor and / or OLPF) . The entire image circle loses contrast dramatically when subject in the frame is relatively bright. I tested it with both the older model and a newer version and the problem was equally severe. Maybe FS7's sensor isn't as shiny or maybe the distance between the OLPF and rear element different than in 7D, 5D, so maybe it does not cause this issue. I guess Ben would know.
I once had the Olympus Zuiko 90 mm 2.0, sold it, heavy but the best lens I ever had. Now they are too expensive. Hope Tamron is also good, less expensive anyway.