I am trying to use a Digital Rebel for portrait photography, however, my meter and this Rebel do not match. I figured out when shooting at ISO 400 I needed to drop my meter to ISO 200. I have since found that no ISO is satisfactory above ISO 100 on the Rebel. So I commenced my testing once again. This time I can not find the sweet spot. Every time I believe I have found the sweet spot my photos come out over or under exposed. Can someone help me out with a ratio or experience in this matterâ€¦thanks Todd.