While I was poking through the images from the trip last week, I came across the photo below, which I took for the purpose of showing a fellow camper what one could accomplish at 25,600 ISO with a 200mm lens at f2.8.
Is it a little crunchy? Yes. But is it usable? Absolutely.
Photographers can be put off (off put?) by the response, “wow, that is a great photo, you must have a really nice camera,” as it is akin to telling a chef that the meal was fantastic and that he must have really nice pans. But in a case like this, there is no substitute for full-frame goodness.