the portable field recorders from foztex are cinema quality sound.
a cheaper alternative is tascam.
the cheaper zoom models have horrible floor noise. better is h5/h6 or Sony XLR-K2M Audio Adapter
whatever you decide, make sure that it has low db noise level, uncompressed wave PCM
the less unbalanced cables you use, the better.
get used to pluraleyes for syncing if you want professional DSLR sound.