[JJ_SO]

In a perfect world scenario the focus field is absolutely flat - so e.g. if you take a perpendicular picture of a wall, the focus field should sit exactly on that wall.

I don't know about you guys, but I'm not buying an UWA for a "perfect world" flat reproduction of maps or huge posters.

 

I could not measure the lens I tried - and looking back and seeing the pictures I was inspired to compose, I have to say, "absolutely flat" would be a physical miracle and worse, nothing to improve my pictures. Long ago I thought enough DoF can save any day, any missed focus and also perspectively challenging shots.

 

12 mm on full frame - how on Earth could such a lens bend the laws of optics enough to be sharpest at some flat pane?

 

The pictures in the tower were very complex in terms of involved distances:

 



 

Pictures like these don't need to be sharp on each little brick or scratch in metal, I'd say.

 



 



 

Do you see field curvature? And if so, does it matter?

 

"... and all that for F4". First, it's f/4, second feel free to develop a lens which covers a whopping 36° zoom range (122.0°-84.1°)  with less distortions, field curvature... Apparently I sometimes can adapt to the fact, not to live in a perfect world scenario  ^_^

 

But if you'd ask me "will you buy it to replace the Nikkor?" I'd hesitate. Although it is much better in terms of flare and offers 2 mm shorter FL. I was not very often in the situation to really need the zoom part of the UWA zoom, but then it was good to have it - the big angle of view sometimes bring in distractive things, then it's good to narrow it a bit.

 

It's not a clear decision to make. I think, Sigma did a fairly cool job with it, but I'm curious about the 14/1.8 as well - and both Irix lenses are as well on my list to play with.