In layman’s terms, the HHT (Handheld Twilight) mode takes multiple sequential images under low light conditions, aligns them, and then create a single optimized image.

It allows you to take a sharper low-light picture without the use of a tripod.

What is diffrence between hht and HDR?

HDR is for High Dynamic Range. When the scene has very deep shadows and very bright highlights HDR can balance it. It can be made from one image or several images (taken at different exposure values) combined into one.

The HHT (Handheld Twilight) mode takes multiple sequential images under low light conditions, aligns them, and then create a single optimized image. It allows you to take a sharper low-light picture without use of tripod.