I’m not a photographer but I sometimes take pictures with a phone. As I understand, HDR mode in IPhone’s camera (I have iPhone 5) expands the number of values in a photograph by merging several exposures. Even though it does exactly what I want I still suspect it’s capable of even more, because when I slide the exposure slider to the very bottom, setting it to the lowest exposure possible, the brightest values are revealed a lot more than in the HDR mode. So, what I would want to find is a mechanical, automatic way to create a gradient of photographs from the lowest exposure possible to the highest and fuse them together. It may be an app or computer software. I think it’s an easy thing to do for an iPhone, the only thing that's missing is the automaticity of it. I can only do it by hand: taking multiple pictures at different exposures. Although, maybe I’m confused and HDR mode is already doing that and it is indeed the most it can do.
I'm attaching a group of photos I took with different exposures and an HDR one.
Thanks for your help!