Keep your 150mm and get another lens. Get one that's not close to the 150mm focal length (heck, a small crop of a shot with 150mm and you have 210mm...). I'd look at a 90mm if you want to go wider or a 240-250mm(or even 300mm) lens if you want to go longer. The Fujinon A 240mm lens is really sweet.
Best,
Doremus
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