Instead of the 2.0/28 or the 3.5/28 I'd take a 2,8/28 AiS. It has CRC and is a very good lens. The 3.5/28 never had a good reputation and is more difficult to focus due to the darker viewfinder image. Whether you take Ai, AiS or non Ai lenses depends a little bit on the type of camera you intend to use.