Why all this fuss?
I use Fujifilm equipment since 2017 after switching from a Sony/Minolta system. The Fujinon 100-400 has been my constant companion ever since. It will keep its place in my bag. Although I have been really happy with the lens so far, there are some inherent limitations:
Aperture: When shooting birds, you use fast shutter speeds. When my subject is perched and steady, I can drop my shutter speed, but as soon as it moves, I usually need 1/1600 sec. or faster. In anything but direct sunlight the f/5.6 aperture means that I am shooting ISO 1600 or higher. In twilight, when a lot of animals are most active, we’re speaking ISO 3200 and above.
Reach: A full frame equivalent of 600 mm should be enough for anyone, right? Well, no! Birds are a very small and often far away subject matter. In a region as densely populated and with so much agriculture as Central Europe, wildlife is shy, elusive and distant. Fitting the 1.4x TC is no solution either as it drops your max. aperture to f/8 and puts your ISO through the roof.
Image quality: Don’t get me wrong. I find the quality of the X-Trans sensors quite fantastic. However, when you’re shooting high ISO and low light, you don’t get a lot of detail. The noise pattern is well controlled, but the noise is smushing all the beautiful detail in feather and fur that us wildlife photographers are loving so much. On the long end, the 100-400 is visibly lacking sharpness compared to most telephoto primes and cropping costs additional detail as fellow wildlife photographer Steve Perry explains in this helpful video.
Please listen, Fujifilm
The Fujifilm platform is not only an absolute joy to use, it meets a lot of requirements of wildlife photographers. Quick and easy to manipulate, snappy AF, well tracking, decent weather sealing, reach-advantages of the APS-C sensor, high burst-rate. What is lacking is the lenses. The 200 mm f/2 does not offer enough reach for most wildlife work, even with the 1.4x TC attached and Fujifilm does not (yet?) offer a 2x TC for it, for the 100-400 see above and this is pretty much it.
So please Fuji: Allow me for a little bit of wishful thinking. A 335 mm f/2.8 or a 400 mm f/4 would suit your system very, very well.
And in the process, please let me set my AE-L-button to “Single Point”- and my AF-L/AF-ON-button to “Zone” -focussing. This would make everything so much faster. So much faster! Sony does it, Nikon does it – you can do it, too!