I'm looking for a good telephoto lens and I found an 800mm OM lens which is for 35mm. What would the mm conversion be over to an Olympus Four-Thirds system? (Basically 800mm in 35mm format = what in four-thirds format?) I just don't want to buy an 800mm OM lens and only get 120mm on my digital camera. I've got lenses that can do this. I'm not up on all the math involved so if somebody could point me in the right direction.