This Vivitar Series 1, 200mm is not something I would carry every day, although its quite compact, its quite a hefty lump at over 800g.
Several versions of this were made, the dearer f3 and the cheaper and more popular f3.5.
Checking the serial number my version was made by komine, Vvitar were not a lens manufacture.
A lovely sharp lens giving you quite a long 400mm focal length on M4/3, with nice bokoh.
Some reviewers claim that CA can be pretty bad, however on my copy CA is pretty minor and very rarely shows, closing the lens down a couple of stops and it usually vanishes.
(For this series I first opened the lenses fully, then closed and set the aperture by just one full stop)