Originally posted by 6BQ5 I don't have one ... but I would be curious to know if the lens vignettes on a FF sensor.
There are some threads about modifying the lens to remove the rear baffle. In theory, this reduces the vignetting and makes the lens fully FF. This lens' patent is FF, but the barrel was modified to optimize it for APSC
Lens profiles are another issue.
One problem with this lens is breathing, so that the 250mm is not always 250mm FoV, depending on where you focus. All IF designs suffer of this to some degree. There were threads about this before. So a 300mm prime
could potentially give you significantly longer FoV. But has has to be sharp. If you buy a cheap lens, it will perform worse than shooting the 60-250mm and digitally cropping it.