Originally posted by slip Would the high ISO performance be better with a crop sensor lens be better then K5iis?
No more than a tiny bit (just the bit that technology has advanced). But nothing* from the sensor size (obviously).
With regards to noise we always only talk about "perceived noise" and that goes up with cropping and subsequent
magnification to output size.
*=But: If the image circle is a little, say x1.2 larger than APSC then you can use it and need to magnify less, which will result in x1.2 less perceived noise.
By the way: Since your eyes don't resolve even 16 MPx from "normal viewing distance" you need to get closer to the output image to gain any benefit from the 16 MPx - thus effectively magnifying it then. Boom. Down goes your dynamic range and up shoots your perceived noise. Physics tell you there is a simple either/or decision to be made: enjoy either lowest perceived noise OR enjoying high resolution/details/sharpness. It is impossible to enjoy both at the same time.