Thanks for the feedback. My favorite time to shoot are close to sunrise and sunset. If an 810 shows up here will put it to the test.My friend has the D810 and as you know I have a D7100 and we have in the past tested a few lenses that we both own with both bodies. To be honest, on checking the images on a pc, I found it impossible to notice any differences although we haven't tried any low light shots. The two main advantages I did find was the ability to crop images by a lot with the D810 and the ability to print enlargements with the FF. As a result of the tests it put my interest of upgrading on hold, however I am always keeping an eye out for any bargains on a D800/810. So providing you are going to do more than just uploading the upgrade will probably be worth it IMO.