Mesh Not Bending to Bone?

First of all, I apologize if this is in the wrong section. I thought Animation would be the best place for armature questions.

I have a hand that I’ve been trying to get an armature attached to, but whenever I bend a finger, the mesh deforms, but only slightly. I’d like for it to bend accurately to the bone but without shrinking in the middle too much that it looks awkward. I’ve tried messing with vertex groups, weight paint, and envelopes, but I guess I’m still doing something wrong…

Here’s some screenshots to show what I mean.

http://img208.imageshack.us/img208/8933/hand3hg0.png
http://img508.imageshack.us/img508/5453/hand1nq4.png
http://img253.imageshack.us/img253/1024/hand2tt8.png

Any help would be appreciated.
Thank you.

Welcome to the wonderfull world of rigging.
2 things:
1: shrinking, again, welcome to the wonderfull world of rigging. you need to be creative and make constructions that help you prevent this effect.
2: that weird thing in your image shouldn’t happen if your thumb is correctly assigned to that bone (tsk tsk, no proper naming for bone?) that shouldn’t happen, maybe you did something wrong? post the blend and we (us blenderheads, I don’t refer to myself as “we”) can look at it.

You have envelope enabled on your bones maybe you are seeing the influence of other envelopes. If you are using vertexgroups (as you are when using weightpainting) deactivate envelopes unless you need them for deformation.

Thanks for the replies. I decided to just scrap the entire armature and start again from scratch. It’s starting to work better now.

That mesh has Subsurf applied right? I think you don’t have enough vertices to make a good joint.

Go in wherever you have joints and put an edgeloop on either side of it.