By the way, i found new Google camera is more useful (not a replacement of Samsung Camera, but companion). It has selective post-focus like the one advertised on S5.

About HDR (true for GoogleCamera and CameraNext): Samsung has non-standard way to activate HDR on S4, that's why HDR mode is not available (and even not displayed in options) on these cameras. I even couldn't find the way how SecCamera activates HDR. It's very custom and looking like in-app implementation (opposing to in-system implementation expected by Google).
Samsung Galaxy S4 SHV-E330S: Optimus ROM (TW 4.4.2) & Kernel. CPU OC 2.7GHz, GPU OC 645MHz, non-KNOX bootloader, UHD/SM/360 Camera.
Samsung Galaxy S4 GT-I9500: Optimus ROM (TW 4.3), Perseus Kernel. CPU No-OC, GPU OC 700MHz, non-KNOX bootloader.
Past models: Samsung Galaxy SIII SHV-E210K & GT-I9300, Samsung Galaxy SII GT-I9100.