The problem with the 70-300cx
Is that the results are so good that it is difficult to appreciate just how long it is. I guess it is only by comparing the images with those which would be obtained by using a 30-110 and cropping that the real value of it can be seen.
I haven't managed to catch one yet ( but hope to next week when I am back home in HK) so can't do that. Maybe someone else can show a comparison.
Of course there is the matter of convincing the FD as well. However I have just sold a good collection of Minolta/Sony lenses so should be in good shape there!