sony 70-400 vs tamron 200-500

If you want to compare lenses, you should be shooting at ISO 100 on a tripod. If one image is a bit darker, then make exposure the same in PP. It may be a good idea to shoot several copies of the same image with the same settings on each lens, refocusing between each and select the sharpest if there is any difference. I know from experience that it is easy to jump to conclusions doing this sort of thing without putting some effort into it.

I have a Tamron 200-500, which I rather like, but these images are not convincing me that it is better than the 70-400.