Bill,sorry but this answer doesn't help much me!...I buy any lens only if it's in good conditions.
I need the best 50 mm,I repeat (i'm sorry...I'm tired too!!!...I'm sorry...I'msorry my friends!) I don't need brightness...I need sharpness,contrast...acutance anything else!!!..This is not a subjective detail, it is an objective detail... It is mathematics:the technical features of any lens are objective,they does not depend on personal taste ...they are equal for all, are universal. It's a picture you get with that lens that is subjectively good or bad ... not the lens in itself...The sharpness,the contrast,the distortion of lens are technical datas that are measured in laboratory scientifically ... not through personal tastes.At least it's my opinion...I hope that you can understand me.I know that write and speak english very bad.i'm very sorry for this.

It would be sufficient only a rapid answer...anything else!...Zuiko 1.4 or Zuiko 1.8...this is the dilemma!
Please don't hate me friends!