Taking multiple shots in Nikon HDR mode

I understand that the HDR mode in Nikon works by taking 2 pictures (one overexposed, one underexposed and then merging (correct term?) together.

But what if the scene has a variety of objects and each has a different contrast...requiring to shoot maybe upto 5 - 7 images instead of just 2. In this case, does the camera allow to shoot 5 - 7 images in HDR or do i need to manually combine the images later in photomatix?

Answer

I assume you mean the HDR mode that the D5100 has. Possible one or two other models. That only merges two shots internally into a JPG. There is no way to take additional shots. If you need more control, you'd need to manually shoot however many shots you need, use RAW and post-process.

If you use Matrix metering, you can select the EV difference between the two exposures, from 1-3 EV

HDR is most effective when using Matrix metering, because the user is given the choice of choosing the difference in exposure value between the two shots from Auto, 1 EV, 2 EV or 3 EV. The camera automatically uses a 2 EV difference in exposure value when set to Center-Weighted or Spot metering.

http://www.nikonusa.com/en/Learn-And-Explore/Article/gltv4qwv/in-camera-hdr.html