I am the satisfied owner of an AF 50 f/1.4 and use it occasionally for indoor "portrait" work of family members (i.e. grand kids). I have an opportunity to purchase an excellent condition 50 1.4 ais lens at a very low price and am considering buying it and then selling or trading my 50 af 1.4. There are minimal reviews available for such older (1980s vintage) lenses and I would appreciate your thoughts. Thanks....and with my best!