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Hi Lea, It is not a malfunction but considered a
feature of this type of zoom. In all the years I have been in photography both
in sales and as a pro this is one issue never “corrected” by any
good maker of zoom/verifocals. Most of the lenses
fall into two categories the push/pull or the dual twist. The dual twist is
usually a faster lens (2.8 3, 3.5 etc) and the push / pull usually has lower
speed but greater focal lengths. Canon makes/made a 100-300 5.6 L push/pull that
was a dog speed wise but light and very sharp. They still make the 100-400 5.6L
and it is a push/pull and has the same trombone effect. The 70-200 2.8 L a dual
twist and suffers no trombone but is not as easy to zoom and focus at the same
time, it takes some practice to learn to use quickly. The
best answer I have seen is simply some gaffers tape if you need to keep the
lens at a particular focal length, just put at the point on the barrel where
you want it to stop. I
hope this helps, Les
Baldwin |
