Weddell Seal, Paradise Harbour, Antarctica
Fujifilm X-H2, 150-600mm, f8 @ 1/2000 second, ISO 800

What would you use? A 200mm f2.0 or a 150-600mm (300mm or a 225-900mm in full-frame format)?

The advantage of the prime lens is a maximum aperture of f2.0 (or f2.8) which throws the background beautifully out-of-focus. Add to this the optics' stellar, super sharp image quality. However, you're stuck with a 200mm (or 280mm with a 1.4x extender), so if your subject is distant, you might not fill the frame.

Compare this with a 150-600mm which gives you a choice of focal lengths, but it doesn't produce the same bokeh (out-of-focus blur) and doesn't have quite the same image sharpness. Don't mis-read this: the latest 150-600mm and similar zooms (whether Fujifilm, Canon, Nikon, Sigma etc) are incredibly sharp, but there is a difference. The primes are sharper still (and at the price, so they should be). Is this difference important?

The photo above was shot on a 150-600mm zoom at 600mm (900mm equivalent), so if I had been using the 200mm, I'd have to crop a lot to get this framing. And after using the 150-600mm for a month down in Antarctica, I have to say I have really enjoyed the zoom and how close I have been able to get to my subject. One specification worth considering is the minimum focusing distance because very often you've only a few metres distance - just a little more than five metres in this situation.

So, in terms of framing, the 150-600mm is a winner. I'm probably never going to get quite the same depth-of-field quality, but what about the sharpness? This is an area where technology has changed the rules. Using Topaz Sharpener AI, I can take what is a very acceptable image and turn it into a super sharp, super clear, perfectly focused photograph. The software really does a great job, so if you haven't played with it, it comes highly recommended.

So, for wildlife, I think I'm beginning to favour the 150-600mm and, if necessary, adding a little critical sharpness with Topaz!