Look what just arrived in the mail. My new-to-me Sigma 18-35mm f/1.8 lens. I found it on ebay and the seller said he had only had it a couple of months. He was switching systems and no longer could use the lens. It appears to have had almost no use. So overall, I think I got a good deal on it.
I took a picture of a deer hide with both the Sigma 18-35mm and the Sony Zeiss 16-80mm lenses. This is not a very professional test sample but it is what it is. I used a tripod and manual focus via live focus check. The shots were at 35mm f/8 and 200 iso. When changing the lens I must have moved the tripod a little because the framing was off slightly. That is why the crops aren't exactly identical in what is viewed. Here's the test shot with 100% crops near the center (Sony first then Sigma). Also, these are from the raw files with no pp.
_DSC8640-2.jpg (427.23 KiB) Viewed 3809 times
Sony 100% crop center
_DSC8640 Lightroom center crop.jpg (158.36 KiB) Viewed 3809 times
Sigma 100% crop center
_DSC8635 Lightroom center crop.jpg (181.6 KiB) Viewed 3809 times
16-80 is definitely a good range and the CZ is still a good lens. The Sigma struggles with af at the wider apertures. If I take two pictures back to back, there's a good chance one will be in focus and one will be out of focus. Stopping down seems to get rid of the issue.
The Zeiss 16-80 is an excellent lens but I don't think its worth the money considering its build quality. The Sony 18-135 has a better build quality in my view. Mind you there are worse in the Sony range. When you consider that its probably made by Tamron as are a couple of other A mount lenses, the Tamron 17-50 with a very similar performance looks like better value.