Why does ls succeed on the jpg?

% #Can someone explain the following? Why does ls on the lowercase jpg succeed?
% ls ./DCIM/100CANON/IMG_0699.*
./DCIM/100CANON/IMG_0699.CR2  ./DCIM/100CANON/IMG_0699.JPG
% ls ./DCIM/100CANON/IMG_0699.JPG
./DCIM/100CANON/IMG_0699.JPG
% ls ./DCIM/100CANON/IMG_0699.jpg # <-- WHY DOES THIS SUCCEED?
./DCIM/100CANON/IMG_0699.jpg
% ls ./DCIM/100CANON/IMG_0699.foobar
ls: cannot access ./DCIM/100CANON/IMG_0699.foobar: No such file or directory
% shopt |grep case
nocaseglob      off
nocasematch     off