Its a great value kit and so far very happy with the results, I have not tried them on a lens less than 20mm fl,
But at 20mm at F4, I struggle to see any problems in the corners of my pictures.
That's the good news , the bad is with the polarizer filter, i did read that some one had struggled with this filter , so i was extra cautious, screwing the filter on so it just on not over tightened, the problem came when i turned the Polarizer, it is a bit on the stiff side, which ordinarily would not be a problem with a normal filter, as you have plenty to get hold of and turn it , .
The problem lays in the fact once you have screwed it on there is only about 1.2 / 1.5mm of the inner ring showing to turn the polarization to your liking if i had turned the filter anti clock wise looking at the lens it might have been ok as i turned it clockwise it tightened the filter in a bit more and i could not undo it with my hand in the end I resorted to a very small screw driver on the filter knurled dial and pushed like heck with my bottom finger nail on the other side, even then it took 4 attempts, at one point i thought it was going to be a a permanent fixture, and i was worried that i might slip with the screw driver and damage my lens, but with a lot of effort it came undone.
The other filter no problem at all, i will use it but i will not screw it all the way in and turn it like i was going to take it off to get the desired polarization effect i want.
Such a shame as i thought i got a result in the price , as the filter do there job.
So if any one knows what Polarizer is easy to get on and off please let me know.
So be warned.