My recent bargain Tair 300 on my K10, and mounted on a vintage Linhoff tripod.
Which to be honest isn't the most stable platform for this gargantuan load in a very strong wind.
It would have been better with the centre column down or on my Gitzo, whatever, this thing demands a good support.
This is the overview, the Tair is focused on the furnace towers in the distance.
The K10 has the standard focusing screen at the moment and I was relying on the focus indicator and my not so good vision.
This is the best picture I got, shot at f16 - 1/400s - ISO 200
Overview, I focused on the church clock.
Best shot ISO 200 - f22 - 1/250s
The Tair 300
I'm going to persevere with this lens as I think it's worth the effort.
Obviously it's not easy to use, needs a SOLID tripod and the camera needs a better focusing screen.
But for £45, along with two other lenses and a Zenit camera, It's worth the effort.