Question On Macro

I have this 100mm Canon macro lens. The other day I tried to take a picture of a fly, but it seems that I could not focus really close no matter how I adjust the lens. It is close but not as close as some of people who could post picture of details of fly's eyes and stuff, I need to take the picture of the whole body of the fly, and not the details of the eyes and stuff.
Please advise. Maybe I am not using it properly...

Try manual focus, AF rarely works that close up. The lens can focus about 6 inches in front of the front element. Here's one I did, probably cropped. You have to lie down and wait for a fly to walk into the right place otherwise they just fly away.

And, make sure you use a really small aperture (large f stop nos). DOF at close range is extremely small, so you need to step down the lens a lot.

nevilleb

You'll find that, as you get really close, it's easier to just move in-out, rather than trying to adjust the lens focus.

Your macro lens will only get you to life-size. If, as I assume, you were shooting an ordinary house fly(well, OK, let's assume a big house fly) it would have been around 1/2" long, or 12 mm.That's about 1/2 the frame on an APS-C sensor. If you wanted to even fill the screen with it, you'd need to add about another 100 mm of extension onto the lens.

I suspect that the images you're seeing of just the eye, etc. is where people are posting crops from just a section of the full image. I don't really understand the point of doing this myself, as they may look nice on screen but you'd never get a decent sized print from them.