The Tamron 18-400 became my wife's most used lens on her Z50 and I shot BIF on D850 and D500 regularly when I wanted light and compact. My optic expert friend who works for Tamron had told me that he was not expecting much out of it when it was announced. When it came out my pro friend and camera store owner in Idaho Falls, ID about 5 hours away got the first sample on its way to the Tamron rep and was shooting Burrowing Owls in Flight with the D500 and D850 before the rep got to touch it. 2 days later he was our now closed camera store here in Boise and when I walked in he had a big smile on his face and was holding the 18-400 out for me to try. I was good throughout the range and had amazing near macro capabilities. Our two copies along with my 600 f/4E were the last f/mount glass to be sold whe we decided to go all in on the Zmount before the used DSLR and F mount glass prices started plunging.WOW Ken, PS whats the Tamron 18-400 like.
My 28-300 is also just a work horse also and its just amazing for the focal range versatility.
I liked the Tamron 18-400 well enough that if someone told me I had to use only one DSLR and one lens the Tamron 18-400 on a D500 would be it.