Amazon.com : 52mm Variable Neutral Density NDX Filter for Panasonic Lumix DMC-GH2 : Electronics
Irix Edge Neutral Density ND8 filter 52mm | Official Irix brand store
Hoya Variable Neutral Density Filter - 52mm — Glazer's Camera
Rent a Tiffen 52mm Variable ND Filter at LensProToGo.com
52mm Variable ND Filter ND2-ND400 (1-9 Stops) with Putter HD 28 Multi-Layer Coatings Import AGC Glass Adjustable Neutral Density Filter for Camera Lens - Walmart.com
NiSi 52mm ND-VARIO Pro Nano 5-9 stops Enhanced Variable ND | NiSi Optics USA