I just have seen that I have the same problem whith the camera raw from phtoshop (LRCC 2015, photoshopCC 2017)
I don't have that camera. I'm still using a 24 megapixel small sensor camera. I looked up the specifications for your model, and it would appear that your camera is set to take a "medium" sized full frame image or a large APS -C image. Here is a screenshot from the online specs:
The Lightroom import process doesn't do anything to your images. In fact, you cannot change the size of an image in Lightroom. It seems that you need to double check the image size settings in your camera setup menu.
Thank you for your answer. You are right my camera was set on aps size when I used it to make a video and I didn't realize that the video settings werre still on. Thank you