sony 70-400 vs tamron 200-500

well I wanted a back up lens to the tamron for when we take long trips as I need a fairly long lens for bird and other photography and in case the tamron goes kapop   and could use the 70 end as well at times. Not easy to buy or rent sony lenses when traveling.  more availability of canikon stuff.

both at 5.6   the sony has more of a CA tendency as well.

I have taken some more pictures and tried to be more consistent and shot at 5.6 I think and f8 and I am still finding that the tamron is consistently better.  sony shoot a bit darker and tamron a bit lighter.    they are all handheld and shot a jpegs with no editing other than how the camera is set - which is the same for all. except maybe shutter speed.  aperature and iso the same.