Trying to shoot rugby in the north of Scotland in winter means little light. For 800/sec shutter speed (200 with TC 1.4) I need to go to ISO 6400 and even then they are under exposed. The resultant shots are so grainy they need a huge amount of processing and then even things like Nik Define is only partially successful.
Does the 1Diii need to go?
Any other suggestions welcome.

