I have Nikon D750 with Nikon 8-15 Fisheye and capturing RAW image in fine mode.
But the problem is when import image in photoshop and lightroom which quality (colors and exposure) reduce from the original file.
Also have same problem in some other program like PTGui but in some other program quality is correct like ACDSee and ViewNX.
OS: Windows 10 64 bit
Photoshop CC 2017
Left side original photo and right side opened in Photoshop
There is no such thing as an "original" raw file. If you could see it, it would just be a very dark and compressed grayscale image. ACR's defaults are by design conservative, intended to preserve as much as possible of the original data captured by the sensor.
The rest is up to you. The sliders are meant to be used.
The camera-processed jpeg/preview is just Nikon's interpretation of how the image should look, and their priority is to make it look appealing. But make no mistake, any raw file has to be interpreted and processed to produce a useful image.