In April I made two trips to Westford's 
Butterfly Place.  I have been there quite a few times over the last few years, but find that I am still able to "capture" new varieties.  Hopefully, too, I can get better and better images of some of the varieties I already have in my growing "collection" of tropical butterfly photos.
Earlier this year I acquired for $100 a brand spanking new Olympus 40-150mm zoom for m43.  It works rather nicely with a 3 foot focusing distance when zoomed to 100mm to 150mm.  At 150mm I can fill the screen with a composition 4" across.  I usually start with the lens at 150mm and zoom out if I want to add more environment to the image.  Of course, I can always back up.
My standard lens for flower and butterflies had been the 70-300mm designed for reg43 bodies.  But on the m43 body it focuses slowly and noisily.  That's okay for flowers but not so much for things that move. The 70-300 is sharpest when zoomed to 100-150mm, and focuses at about 3 feet.  But it has slightly more magnification than the 40-150.  At 150mm I can fill the screen with a composition that is 3" across.
Nevertheless, I think the 40-150 for m43 is a better choice for me.  It focuses fast and quietly and is very lightweight, which I notice after my (typically) two hour butterfly sessions.  By the way, the 40-150 is light because it is all plastic, even the lens mount.  I'd rather have a metal lens mount, but for $100 I have nothing to complain about.  As far as I can tell the optics are excellent in the range I am using for butterflies and at my preferred aperture setting of F8.  Though I don't get quite the magnification I have with the 70-300, a bit of cropping isn't particularly problematic with the 16 megapixel sensor of the E-M5.  When I started with the 70-300, it was on the Olympus E-520 which was a 10 megapixel sensor.
I used a flash during both April sessions.  The flash is a Metz 50 AF-1 to which I attached a cheap deflector.  I also have some other deflectors I expect to experiment with.
I used manual exposure settings.  Almost always I shoot at 1/250 and F8 and whatever ISO is required to provide underexposure of about one stop.  I then set the flash at TTL.  I use flash exposure compensation if adjustments need to be made.
Below are my two favs from April.  Neither specie was in my collection so I was happy to have seen these specimens and also to have found them in perfect condition.
|  | 
| Emerald Swallowtail | 
|  | 
| White Peacock | 
The rest of the images from my two April outtings can be viewed on my Web site, here:
9 images from April 7 at
9 images from April 20 at