35mm lens adapters cost thousands to buy, hundreds to build, degrade the objective technical quality of your video and make your camcorder an entire magnitude more difficult to use. And they won't make your video magically look like film. Nothing will.
On the other hand, by adding selective focusing options to small consumer camcorders, 35mm lens adapters have the potential to produce some absolutely gorgeous images. Do you need one? No. Do you want one? I know I do!
This is high-def dual system production done with a sub $300 SD780IS point and shoot still camera. It has a 720p mode which records H.264 video at 30 frame and 16/44.1 uncompressed audio. We shot dual-system with a Sound Devices 702T and slate-synced to show the difference that quality audio makes to improve the production. Note that Vimeo drops the frame rate to 24 frame and adds more compression.