Samples data: imaging-resource.com.
☆Canon EOS 500D vs. Eos 50D ISO100-12800 Comparison.
From ISO100 to ISO400, The 500D's resolving power is better than 50d's .
However, when becoming high sensitivity, 500D's resolving power is not good.
At all ISO, The 500D's noise is concealed better than 50d's.
☆500D VS. 50D ※Click to enlarge.
ISO100-800 ISO1600-12800
ISO100-800 ISO1600-12800
※500DExif and 50DExif/ISO12800.