misolo,
If add other fasts, I agree with you that lens makes difference, and the easy example is Sony RX100-M3 has better IQ than RX10 in SAME higher ISO. Of course, primes are optimized for its focus length and it has less number of glass than zoom (not mention it is faster).
BUT, before we make things complicated, as you mentioned crop fact, lets look the ration of sensor area (sensor area is directly reflecting to Pixel size) in mm2:
– APSC/MFT=370/225=1.644.
– 1/1.7″/1/2.3″ = 43.3/28.5=1.519
The difference between APSC and MFT is greater than 1/1.7″ and 1/2.3″, is it not? I think most of the people agree 1/1.7″ sensor has better IQ than 1/2.3″ sensor. Do you agree?
Started out doing photography at the age of 6 using an uncle's old 1940 kodak brownie box camera. At 15 years of age, I decided to buy my very own 1975 Praktica SLR camera. I now shoot with a Nikon D850. I do unpaid TFP and commercial paid work.