Can an iPhone 4S take HDR pictures without an HDR app?

I saw an HDR button on the Settings menu.

Yes open your camera go to options and turn HDR on. Simple as that.

Yes it can, go to camera, options then you'll see HDR and just flick that on.

On your homescreen->camera->options->switch on HDR

Then wenever you take a pic there will be two photos in your camera roll-one HDR and another normal 1