I really like to take pictures of insects, close up...get their eyes, their hair, or the texture on my bearded dragons toenails, etc.
I've used a 28-135 (on a canon 7d) at 135 and just gotten as close as possible to the subject. This has mostly worked.
Is a macro lens a better tool for me? What does it do that my current method doesn't do? And if I'm standing super close to the subject, does the 100mm macro just zoom closer than the 40mm macro? Or am I really just looking at the speed of the lens at that point?