I'm looking for a premium lens (fast & long FL).
The first lens I got my eye on is the 300mm F/2.8 - an awesome lens.
But those seem to require a gimbal head and I can't just carry it around my neck - like at the zoo.
So, what will be the biggest lens someone can reasonabily carry around without looking ridiculous or getting attention from authorities ? I am looking for fast and long (I know this means a HUGE lens), so zoom isn't necessary.