How to edit pictures like this?

I know it was shot with a Nikon D3000.
I have a Nikon D5000, but I'm just wondering how he edits it.
How does he makes the edges/around it look black?
Or is there something he does for the picture to come out that way?

It was in a darker room, nothing was done other than taking the pic and it looks a lil under exposed too.
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However, he could have darkened the background a bit with any image editing program to make the 2 people stand out more.
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The make and model of the camera matters not…

Looks to me like they were out in the dark, and he Turned on the flash, usually making the background almost black.

It was shot with a fisheye lens and a flash. The lens is too wide for the flash to effectively cover it.

According to the EXIF, the lens is a 5mm, so it was probably cropped as well

It looks like it was shot outside at night. The flash lit the people in the photo, but not really anything behind them; it couldn't reach far enough back. It doesn't even look like he edited the photo at all.

A photo like that is easily doable with any camera that has a built-in flash. D5000 is included there.