In article <3295931C.32A6@ncl.ac.uk>, Fei.Xia@ncl.ac.uk says...
[......]
>The 28-135 scores very highly in Dave
>Reuther's lens evaluations and I agree with
>all of his points. However I was never
>happy with it. Why? Because of things he
>chose not to mention, such as the looking
>through a hole effect. I did not notice the
>very bad light falloff because I was doing
>mostly negative film for small prints and
>my printing shop apparently has an enlarger
>lens with its own bad light falloff which
>cancelled out the problem! Slides and
>prints from better shops, of course, made
>the problem prominent for everyone to see.
>
>On the other hand when the field is not
>evenly illuminated to begin with and even
>brightness is not psychologically expected
>by the viewers the lens was brillant. The
>point however is that with a one-lens
>system one has little chance of avoiding
>that particular lens' shortcomings save for
>refraining from taking a shot from time to
>time.

Umm, I did not note the illumination problem
with the 28-135mm f4-4.5 MF Tamron, since I
did not find one with the two I tried....
Are you perhaps using a shade other than the
one designed for it? My one complaint with
the lens (other than its current unavailability
new, its need for the very large special shade
designed for it [and the 35-200mm Tamron], and
the rather strong pincushion distortion near
the long end) is its minimum focus of about 7',
though it does have a second rear helical focus
ring for going closer (but that makes the lens
vari-focal). This, and the Nikkor 24-135mm,
do make me think that high-quality wide-range
zooms are possible - but most that I have seen
have bordered on (or wholly entered the
territory occupied by ;-) terrible lenses...
No degree of convenience is worth the trade-off
of high image quality for me - an image taken
unsharp can never be made (really) sharper later...
Hope This Helps