The Letus35 Extreme Bundle is an entry level 35mm adapter with only 1/2 stop of light loss. The perfect choice for the budget minded Indie Film maker. The Letus Extreme is designed for entry level / beginner film makers. Although it similar to the higher ends Letus Elite, it lacks a few features bringing it in at a lower price point. Most notably, the Extreme lacks the back focus adjustment ring and upgraded optics found in the Elite. These items can be added separately if you want to upgrade an Extreme to Elite in the future. The Extreme was the first 35mm adapter released when Letus re-launched in 2007. It revolutionized the 35mm adapter market and many tried to copy the innovations it was built into this adapter. This was the first 35mm adapter to seamlessly integrate a prism based "flip" optical path which produces an up-right image in the camera. This one piece design makes for a compact and light efficient adapter. Unlike other adapters on the market, there is no need to purchase a separate "flip module" to achieve an upright image.