I've been researching online for too long and need your help With the disappointment of the Canon 6D mark ii I'm trying to decide between a very expensive upgrade to the Sony A7Rii with the Sigma 24-105mm F4 lens or an easily affordable minuscule upgrade (currently using a 70D) to the Canon 80D with my existing Sigma 18-35mm F1.8. My question is, how will the noise level and low light capability compare between these two options? The 80D with f1.8 VS the A7Rii with f4. To clarify my dilemma, it's more than just a financial problem, I'm finding it hard to believe most high end cameras don't include a fully rotatable touch screen, and the Sony lens options are more limited than Canon - there's no sony mount for the Sigma 24-35 f2! But all things considered would it be worth spending the extra cash?