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....