Grainy image from CCTV

So I just purchased the Swann SWDVK-845808. Considering the large BNC connectors, I thought it was a good idea to chop and solder the power connections at the camera, to help feed it through the hole in the wall (I came to this conclusion after I realised I had the cable fed with the wrong end and it seemed like a win/win solution). It was already 18mm and that pretty large, so I wanted to keep it to a minimum. My image is grainy and seemingly of low quality and I can not help but wonder if my adaption is the reason why... Worth noting, I have also connected it in the same fashion at the power input near the DVR.

I grabbed another camera and connected it up, no wires cut. Put it in the same position and it seemed equally as bad. So why would a 1080P camera have such a terrible image? Working on uploading an image.

It would be bad because of the BNC connections. Just because it has so many pixels doesn't mean that it is any good.

This is the reason I went for IP camera setup, where there is only 1 cable that supplies both power and picture. So simple.