Why is that?
Again F2.8 is still F2.8 regardless of the system. It took me a while to find the truth in this
I have the Nikon 70-200 F4 and I don't plan to get the Fuji because it is too heavy, similar as the Nikon 70-200 F2.8. If I change my shooting maybe but for now the 55-200 F3.5-4.8 is good enough.
Of course an f2.8 lens is an f2.8 lens. This is the last marketing fashion trick launched by this super pro forum called DP sumthing or some another internet valorous bible
. The 50-140 on a fuji is far from a 70-200 f2.8 on a Nikon just because those lens are strictly different.
We buy telezooms or long lenses generally for two things : Reach and bokeh.
On a 24x36 sensor you have both, especially at 2.8. On an APS-C you will only have the reach. The rest will be close to what you can get with a 70-200
f4 and even, because of the aps-c sensor, modelling is out by a large margin.
So, having an APS-C for landscape, aviation, bif, sport: it is superb. If you want to go serious : increase the size of the sensor.
If you want to be close to the lens drawing and bokeh of a full frame 70-200 f2.8, I repeat, you'll need a 50-140 constant f1.2. >> this is just mater of facts, not forum bickering mixed with dance-floor sorcery.