Originally posted by photoptimist Nice tests!
Another 28 in the menagerie is the Pentax K 28/3.5 Shift. This lens can easily flare from the sun -- creating rainbow bubbles on a diagonal opposite the sun. Even if the sun is out of the visible frame, it may be within the ultrawide field-of-view of the lens. Shading the lens with a card or your hand can block the sun and kill the flare.
It is really hard to find a lens hood that will achieve much without vignetting on FF with the 28s. The old square original are probably the best bet. But obviously for here I chose to let the sun hit the front glass. There is really 2 basic sorts of flare isn't there. The artifacts from the sun hitting the front element (and the Tak Bayonet is very prone to that) and general sort of contrast loss which I think the Tak bayonet seems to handle well. More to the point it loses contrast but seems to render particularly well when bringing it back in editing. My Tak Bayonet 135 2.5 is the same.
And for the record the shots were out of camera jpg.