Hello, I'm new here and just aquired a Mamiya RB67 Pro S body. I had shot with this little gem in the past before but this is the first one I've owned in 20 some years. Currently shoot digital Nikon. But I am in the process of trying to decide on a lens for the RB67 Pro S. Can you please advise which would be best for landscape such as star trails etc. and then also one for portraits. Also does the RB67 Pro SD 120 back work on the RB67 Pro S? Thank you all for your help with this, much appreicated.