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
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※500D
Exif and 50D
Exif/ISO12800.