Shooting with extremely long lenses like the 150-600mm Sigma requires higher shutter speed and to compensate for this, higher ISO levels are required. This gave me a chance of seeing the result of using 6,400 and 10,000 (and higher) ISO sensitivities. And I will tell you I am extremely impressed. I have a hummingbird picture at 6,400 that is perfectly fine. I’m sure if I subjected it to very close scrutiny and blew it up to 200% I’d find issues. And that would be crazy. My point is this camera has really excellent 6,400 ISO results. The next test is to take some photos at that sensitivity in a low light indoor environment. If it passes that test then this is the camera I was looking for when I was looking for a successor for the Sony A-850 in 2011. The A850 was a great camera. It had a best in class 24 megapixel sensor and shot beautiful 100 ISO photos. Even 200, 400 and even kinda sorta 800 ISO photos were also very good. but try to take photos in a restaurant at 100 or even 800 ISO. You’ll have motion blur and worse. So I used to take 3,200 and 6,400 ISO shots that looked like a Monet painting with color noise swirling around everything. I tried to convince myself that I liked the result but it was pathetic. Now here I am a mere seven years later and all’s right with the world. Well, that’s assuming the indoor tests go as hoped. That also assumes the low light autofocus is as advertised. Stay tuned. Results will follow soon.