Sweet toys, especially the 100mm IS. Wonderfull lights to it.

On the weekend I will inaugurate them. Carnival is a long holiday here and I will have a lot of time to experiment. 

I also have that lens...love it as well.

I was a bit disappointed to discover I can not use the in-camera flash to trigger the flash off-camera, but it works ok on-camera too

I had the same experience. You have to buy the Transmitter that goes on-camera, then that will trigger your Speedlite off-camera and other off-camera flashes.

Where did you get yours? 

Lens and speedlight from B&H. 

Mel, the cost of the 580 is prohibitive, especially given that my use is very rare. 

Cclpper, thanks for the tip, I'll think about it.  Does it need to be Canon's? 

My mistaken was that I had thought a Canon speedlight would work off-camera.  My first SLR was a Canon, back in '82, and later I purchased a cheap speedlight, and later a Canon speedlight.  The later could be triggered off-camera by the first, if I remember it right, just by the light activation.

A 430 instead of a 580 wouldn't work?  The in-camera flash plus the 430 as a helper would probably suffice for my use though.

sweet lens. looks like you are having fun with that.

I found 1/60s to be a limit speed for me. Unless I got some support, anything slower was blurred.

Do you have a full frame body?

I have also gotten hold of the 100 IS. It is fun, finally I can shoot small objects. I need a lot more time learning how to use it effectively, though.

sweet lens. looks like you are having fun with that.

Still learning.  I need a new tripod, my old one (very old, like 25 years) broke last year and the light one I use in travels (a 450g Slik) isn't strong enough for vertical shots and also very low (I have to crouch to use it!).  Then I can try real macros with the new lens. 

That would explain the 1/160 speed limit. Your crop factor makes that lens about 150mm.

Actually, it's 1/60s, not 1/160s.  I read in a forum - SLR Gear, I think - people say they can shoot 1/20s with IS.  Well, maybe if you have a steady subject and some support, but I definitely can not do that just by holding the camera in front of my eyes. 

Another image.  I missed the focus just slightly, and if correct I would have captured the eye texture - creepy! I liked the result, given the conditions: it was on the top of a very long stalk about the height of my eyes, so it was swaying back and forth, left and right, far from ideal. Ok, not a winner, especially with a petal covering its proboscis. I tried a few shots without flash, but the bug was facing its back to me. This was shot with the in-camera flash, ISO 400, f/5, 1/100s.
http://www.shutterpoint.com/Photos-ViewPhoto.cfm?id=786931

I also saw a big orange ant, but it ran too fast.

I should also add that the manual suggests using AI Servo mode in macros, but I didn't find it effective in the few attempts, it was actually losing focus everytime. Perhaps if I use it on a subject that very clearly separates from the background, it will work better. Not to say it's enervating to have that constant buzz.

BTW, what sort of bug is this?