Sprite's blurrinness change with size of camera

I don't understand why my sprites are blurry, in the scene view they are correctly displayed so why it can't be the same in game ?!
Also the blurrinness change with size of the camera, with a smaller size of camera it's less blury.

PS: Normally the camera is bigger to have a full view of the scene, here I zoomed so we can see the blurrinness better.

With camera size = 9 : With camera size = 3: