Hi Igor,
Thanks for the link.
Tamron needed to update their firmware - a reverse engineering project - which could not begin (as Canon provides no guidance to competing optical mfg. co's) until the M3 was released.
I had the classic firmware clash with my tamron 16-300mm on the M3 (+ ef-m adapter). Simply a no go. So the 16-300mm remains mounted on our SL1 (my wife's favorite camera) - and probably is used for more images than any other lens in the collection (~75 - way too many, ugh).
Regarding the tamron 18-200mm Di III VC PZD (EF-M mount), By carefully reading numerous sales listings, I was able to find a seller parting his M3 kit who had sent this lens to tamron & had updated the firmware - thus, it was (is) compatible with the M3. That's why I purchased it. It's a nicer "fit" on the svelte M3 than its 16-300mm Di II sibling w/ef-m adapter.
This (Di III,ef-m mount) particular tamron is more compact/lighter & imho, has a nicer - piano black - finish/build than its 16-300mm sibling. I find both of these lenses to be useful - the 16-300 on the SL1 and the 18-200 on the M3. I also have the 28-300mm Di VC PZD for my full frames and aps-h, although it has been used infrequently.
Good luck with your second body. I usually shoot with a DSLR as my main - and either the SL1 or a mirrorless (M3, X100s, XT-1) as my second. Lately, I've actually shot full mirrorless with the XT-1/M-3 combo.
Enjoy!
dale











