Old schoolers. like me, look at 1.4 and 1.2 and say 1/2 stop. Digi-togs call it 1/3. Tech specs vary by maker and within a maker. Light transmission, T stops, can also vary. Other specs also not specific. Many know that 70-200 is not always a true 70-200, and to Canon, 103-383, is referred to as 100-400.

This not like comparing 85 1.8 to the 100 2, like builds, 1/3 stop as stated difference. Similar build similar, but not the same, iq.

I agree with those before me that have stated two disparate lenses with much different iq, build, af abilities and oof rendering.

For me, like the 1.4, it is ok, love the 1.2, yet it has its own, and known, foibles.

Gochugogi wrote:
It's not as simple as F1.2 vs 1.4 as there are many other reasons to own the 50 1.2L such as quality of bokeh, AF speed and reliability, increased build quality, reduced distortion below 2 meters and better IQ at or near wide open.

Exactly what i was going to say.

I own both and the 50F1.4 has gathered dust since i got the 50L. Same as with the 85F1.8, it's gathered dust since the F1.2L II arrived.