I understand the metabones speed booster will give you an extra stop and 35mm frame coverage. Using the BM 2.5k camera with EF mount, would it work if I placed a metabones EF adapter on it and used my EF lenses to give me the extra stop and 35mm coverage? It sounds weird because I am not adapting other lenses to fit, I am using the same EF lenses on an EF camera, but from what I've read it could work well. The only problem with this is that I do not believe an EF to EF adapter exists! I contacted Metabones, still awaiting response.