Accessible Virtual Reality (VR) navigation remains challenging, particularly using subtle hand gestures. We propose and evaluate SubtleNav, a system that enhances conventional hand tracking using real-time motion magnification. SubtleNav aims to enable precise and low-effort steering control in a VR environment. A preliminary study compared control success rates between SubtleNav and conventional hand tracking, showing that SubtleNav improves success rates for less dexterous fingers. However, it also introduces a trade-off, negatively impacting stability during fine control and state maintenance. This work demonstrates the feasibility of video magnification for enhancing subtle VR interactions while highlighting the key sensitivity-stability balance that requires further investigation.