Best Macro Lens for D3100 for Nail arts?

I'm starting a Nail blog, and I have the Nikon D3100 with lens kit and also the 50mm lens f/1.8, but both can't seem to capture my nails, so I'm wondering what is the best macro lens out there for me? I'm still in college, so my budget is around 200-400. I would prefer auto focus, because I only have one hand to take the picture of my other hand. But i think those are limited and probably a fortune.

The kit lens and the 50mm are not macro lenses - so they can't focus close up.

You could buy a maco lens but I think your budget might still be on the low side. However, there are other possibilities such as extension tubes - much cheaper than buying a macro lens. Buy one that has the electronic contacts inside so that the camera can still control the lens. Kenko make good ones. Here's more info on what you can do with extension tubes: http://digital-photography-school.com/extension-tubes-close-up-photography-lesson-2

Also get yourself a tripod - that way you can keep both hands free - a shutter release cable might also be helpful.

If you do want a lens round about your budget - Sigma produce two very nice ones that might do. Their 50mm and 70mm F2.8 EX DG Macro lenses http://www.sigmaphoto.com/...f_combine=

Another thing you could do since the images are for the web, is to take a picture of your nails as close as you can with your existing 50mm, but far enough away so that they are still perfect focus - then just crop the image. You'll be surprised how close up simple cropping can make it look.

You're better off getting a simple tabletop tripod (like the Gorillapod) plus a remote (under £10) first. DSLR's are not meant to be hand held in one hand for starters.

You then have the freedom to position your hands where you'd like. Focusing as close as you can with the 50mm f1.8 will give you a sharp image which you could possibly crop. It will also remove the (possible) problem of shallow depth of field that you'll get with a macro lens

If you really need close focusing than then best (cheapest) macro lens I can recommend is the Sigma 50mm f1.8 macro. If you do decide to get extension tubes instead, then get the 'Kenko' brand, as they have electronic contacts in the tubes that mean that you get to keep metering/autofocus.

Your 18-55mm lens can focus as close as 11'' which should be close enough to get the detail you want to show in your nails. You definitely need a tripod and a remote release if you're working alone.
Use a couple of small desk lamps - one on each side - to get good even lighting of your nails. If you shoot in RAW its easy to correct the white balance with your editing program.

Had you bothered to read the Owner's Manual for your lens you'd have known how close it can focus.

These images are for a website? Then you don't really need a macro lens.

Shoot with good light up to your normal focus distance and then just crop. Now, if you wanted to do large prints of these, the loss of pixels from cropping would be an issue but you'll be compressing that image down anyways for web use (600px probably on the longest side from like 3000px+ from your camera.)

"I would prefer auto focus, because I only have one hand to take the picture of my other hand."

Just use your 18-55 and get yourself a half decent tripod (anywhere from 50$ to 200$) and a cheap IR trigger (around 40$) for your camera instead.