Ok here we go...
Kiron 28 2.0 -- 9.00 (6 reviews)
FA 35 2.0 -- 9.10 (51 reviews)
M 50 1.4 -- 9.16 (71 reviews)
Thus the average is 9.09 ...
But unfortunately the rating of the Kiron is not as significant as the others, given the small number of reviews...
Let's introduce a portability-weighted average
<p> defined as follows:
we call
M the weight of the lens (I'll use grams, following strictly the SI units, but feel free to use what you like, we normalize in the end
), and
r the average rating of the lens.
The smaller
M, the more portable is the lens, thus we use as weighting factor
1/M, and consequently the
sum over all 1/M's to normalize the final result.
W(Kiron) = 261 g (with lenshood)
W(FA 35) = 202 g (with lenshood)
W(M 50) = 241 g (with lenshood)
Thus
A == r/W (Kiron) + r/W (FA35) + r/W (M50) = 0.1175.... rating-units/g
The normalizing factor is,
B == 1/W (Kiron) + 1/W (FA35) + 1/W (M50) = 0.01293.... /g
And as final result we get
A / B = 9.0865.... rating-units
Though this didn't change much for me, but for those of you trying to score high by adding you A* and FA* telephoto lenses :P :P....