Butterflys are one of the easyer things to sneak on, the current camera i use has a fixed lens of 38-380 equivalent, (although i do shoot 35mm SLR with a tamron)
for the macro mode on this these are my focusing distances
7cm macro mode (38), 120cm (380)
so at minimum zoom i need to be around 7CM and at max 120CM, usually ill get close in and work on minimal zoom
3cm 'Super Macro' mode (no zoom)
This is something im not sure u will have but iv still managed to sneak up on butterflys with this one (dragon flys are another matter)
When using reverse lens macro my focusing is right down to mm and the amount of shots u will need if the thing moves u have to start all over again.
Each lens will have its own point that it will focus at and differing DOF (amount of area in focus) usually the more you pay the better you get, your best bet is to take your camera to jessops and try out a few lense (both dedicated macro and tamron zooms with macro capability) take a coin out your pocket, put it on the counter and fire a few macro shots on each to test out the focus distance for varying zoom, DOF and image size You then have something you can take home to compare results and decide. For shooting butterflys and such Macro filters will actually provide acceptable results at a fraction of the price, For me a dedicated macro lense is something i would only consider using for shots such as detailed ants climbing a blade of grass, flora fauna bugs n creepy crawlies can all be shot with macro filters and/or a tamron zoom (macro) lens.
