Canon 400D (Rebel XTi) vs. F50 FD ISO performance.
All pix are 100% crops from a full sized pic.

Canon 400D (Rebel XTi)

Fujifilm F50 FD

Canon 400D ISO 100
F50 ISO 100
 
Canon 400D ISO 200
F50 ISO 200

Canon 400D ISO 400
F50 ISO 400
 
Canon 400D ISO 800
F50 ISO 800
 
Canon 400D ISO 1600
F50 ISO 1600