So I have the 11-18mm. I very nice lens. But it is soft on the edges. My Olympus 9-18mm was sharp as a tack. But the Sony IQ is better. What other option other than the 11-18mm that might be sharper. I see a 10-24mm Tamron but it is priced about the same as the 11-18mm so I guess the sharpness would be about the same as the Sony.
Anything else out there? I landscape so MF is fine.

Tokina 11-16/2.8
Sigma 8-16, 2 types of 10-20 & the 12-24.

my understanding of the Tamron 10-24 is that it's actually not as good as the 11-18 but has the wider range.

The best out there is the Sigma 7-16mm. I have owned the 11-18mm (three versions!) and actually rate it as pretty good, the geometry is superior to most other lenses. And the 10-24mm, and both Sigma 10-20mm (we still have one of the earlier models). The Sigma 8-16mm beats them all by a very large margin. We have the Olympus 7-14mm and that is pretty good

David

Thanks David. I will look at the Sigma. I agree the 11-18mm is a nice lens. Not to much distortion.

I used the 8-16 on my Nikon D7000 and would still be using it if my D7000 didn't need a windscreen wiper on it's Sensor but thats another story, an absolutely Stellar Lens but you must use it wisely and also try not to get your feet in shot!