The Canon EOS 90D has no problem in shooting in low light even with a telescopic lens I was able to pull a beautiful picture in low light I know you see the lights across the street but it still was no light where I was at and I still pulled a reflection off the water I mean the 90D is amazing. You know I actually zoomed in I didn't see too much noise and you can actually got to take it out of high tone priority if you know what that is and you can get a clear shot with high tone priority of and you can use a faster lens like the 50 mm or the 24 but this was the Rokinon 1.5 35mm manual focus. And yes the 90D does have manual focus peaking. One day I actually had any manual mode and I was looking at the blue on the screen but I had it connected to the phone and for somebody reason the phone didn't show the blue that was on the screen so I figured I was getting some chromatic energy in there so I was trying to change the temperature of it but that's not what it was The camera was telling me that it was focus speaking for me isn't that amazing focus speaking definitely help when you shooting with a manual lens.
