Instruct: Classify Amazon reviews into positive or negative sentiment
Query: disappointment with early AF failure

I purchased an EF 50mm 1:1.4 for my new EOS Rebel XTi about 6 wks ago. It worked great for about 70 shots, then the autofocus abruptly quit working and has not worked since.My other two lenses, the standard EFS 18-55,and an EFS 70-300mm, both work fine in AF mode.The EF 50mm lens takes very good pictures in MF mode,but I am very disappointed that this lens failed so soon. I would otherwise rate it a 5 as far as quality is concerned.