Can you expand a bit on what about the 50 f/1.8 Z you find lacking compare to the other 50's you mention. Is is the 1.8 vs. 1.4? Do you find the bokeh not as pleasing? Is it just to clinical?
While I have several zooms that cover the 50mm range, the only 50 mm that I use much is the Nikon 50mm f/1.8 G. It is tiny, cheap, and gives results that are good enough for me. But I am really just a hobbyist, not a professional. I have never had the opportunity or need to shoot any of the 1.4 or 1.2 50's from Nikon.
I also just recently picked up the 40mm f/2. Not a 50, I recognize, but still small, light, and so far pretty decent. I admit that I haven't shot much with it yet. I do hope to pick up the 50mm f/1.8 z at some point, so I would like to hear more of your thoughts about it.
Usually, yes. Not because of the stop as much now that ISO has gotten so much better, but because that extra stop comes with a lot more quality usually.
Usually.
When you are comparing any two lenses, you have to compare just those two lenses because nothing about lenses is generalizable, and often you even fall into the "you have to get a good copy of that lens" argument as well.
The Nikon 50mm f/1.2 is a great example of why it's not a stop you are really asking about. The difference between f/1.2 and f/1.4 doesn't mean much for ISO, but at f/2, absolutely nothing beats that 50mm f/1.2 for image quality.
Ultimately, your decision depends on money, how much you are willing to carry, what airlines will allow, the final image that you want, and the final image that you can sell.
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