Since its release in 2017, Sony 24-105mm f/4 lens has been a hit. It is the beginning of July 2018 now and the lens is still on preorder in all camera stores.Yes, small batches have been released and if you pre-order it is most probably that you will receive one soon, but it is not available for direct buy online.
While waiting for this lens to come, Tamron announced, and later released, a brand new 28-75mm full frame lens with constant f/2.8 aperture. It was probably released to compete with the Sony GM 24-70mm f/2.8, as many of the reviewers jumped to compare the two. Yes, both lenses have similar focal length, and both have constant f/2.8 aperture, but pricewise are very different. While the Sony GM 24-70 F/2.8 is almost $2,200, the Tamron 28-75mm f/2.8 is only $799.
Couple of weeks ago my Sony 24-105mm f/4 finally arrived. Because there were no signs that it can be delivered on time for the two upcoming events I had to shoot, I decided to rent the Tamron 28-75mm f/2.8 as well. At the end both lenses arrived on time, so I had the opportunity to shoot with both lenses at two weddings, and also use them for some casual family pictures.