I have a simple question for all of you who own big F2.8 to F4 telephotos (and by big telephotos, I’m referring to 500mm or larger): how often do you actually use them? The reason for my question is because I’ve been weighing getting a 600mm f4 lens, but because of its size and weight, I wonder how often I’d actually use it. For me, when in the field, portability is paramount, and as I age my ability to handle big glass for long periods of time is diminishing. Travel by air also has its baggage restrictions. While I completely understand the advantages of fast glass, I also hesitate to spend $15k+ on something that I might end up keeping on the shelf more often than I should because of its unwieldy size. I realize the answer to this question varies by individual situation and ability, but I’d be curious to know just how frequently you actually schlepp your big f4 lenses into the field.