A friend of mine gave me this lens a few years ago and I completely forgot about it until a week ago, when I found it while searching for something completely different 
Not a lot can be found online about this one, I see it has colour filter inside so the question is will that affect the image quality? But I suppose IQ of it won't slow me, I am interested in the effect of the filters on bw photography, more important question is - what purpose serves this platic that goes over the lens?

Not a lot can be found online about this one, I see it has colour filter inside so the question is will that affect the image quality? But I suppose IQ of it won't slow me, I am interested in the effect of the filters on bw photography, more important question is - what purpose serves this platic that goes over the lens?




