New Tamron 70-180mm FE reviews do confirm this $1,199 lens is actually sharper than the $2,599 Sony GM lens!

You can preorder it now at BHphoto, Amazon, Adorama and FocusCamera. In Eu at FotoKoch DE, Calumet DE, WexUK and ParkCameras.

Marc Alhadeff from SonyAlphaBlog just posted the first full review of the new Tamron 70-180mm f/2.8 FE lens. He writes:

The Tamron 70-180mm F2.8 Di III VXD (1499 euros) is an excellent lens proposed at a very reasonable price. It completes perfectly the 2 other Tamron zooms but the quality of this zoom is clearly higher than previous Tamron Zooms. Indeed it supports perfectly the 61Mpix of the A7RIV whereas the 2 other zooms where showing their limits on the A7RIV

To achieve this performance at this price and this reduced size and weight Tamron had to make some choices:
180mm instead of 200mm
No optical stabilization
Lens extends when zooming
No “fancy” buttons on the barrel
No tripod foot (but you don’t need it considering the weight)
Not compatible with Sony TC

All the above compromises do not influence at all the image quality that is excellent (sharpness and bokeh) and allow for a weight and price divided by 2 compared to the Sony GM

Pros
Excellent sharpness on the entire field and entire range at all apertures
Very small and light
Very reasonable price
Very good bokeh and soft background blur
Extremely fast , silent and accurate AF
Very low level of chromatic aberrations
Moderate vignetting
Very good resistance to flare
Fully weather sealed

Average
Color rendition little bit yellowish
Not compatible with Sony TC1.4 & TC2.0
No button to switch to MF, to set a custom function, to limit focusing range
No optical stabilization

Cons
Huge distortion between 135mm and 180mm (no lens profile yet available as of April 2020)
Lens does extend when zooming and the zoom ring is quite dampened , so no smooth zooming possible in video
Does not look “Pro” if your are pro wedding photographer

The Tamron delivers similar performances to the Sony FE70-200 F2.8 GM in most cases and even surpass it sometimes (corner sharpness and sharpness at 180mm, portability) at half of its price. A superb Performance !

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And this is the video review from Scott Dumas:

You can download his samples photos at https://geni.us/tamron70180sony

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You can preorder the new Tamron now at BHphoto, Amazon, Adorama and FocusCamera. In Eu at FotoKoch DE, Calumet DE, WexUK and ParkCameras.