20mm f2.8 Back/Front focus issues

Puljak wrote:

ttbek wrote:

At infinity you say? Are you sure? Most lenses for modern digital cameras will focus past infinity, this is done because they assume people will mostly be using autofocus and it gives more tolerance for variations in the mount manufacturing. If you got to infinity by turning the lens as far as it goes than it is almost certainly actually focused past infinity. I have never experienced front or back focusing with a mirrorless CDAF camera. Sometimes I have seen some other things, like where it actually focuses on the hard edge of a bokeh ball instead of the actual object. Some NX cameras do have PDAF, but it is at the sensor plane and also should not be able to have front or back focus.

I can turn the focus ring as much as I want because it does not have the range limit, it's focus-by-wire.

This is rather my point, there is a hard stop for the actual focus element in the lens though and unlike many old manual lenses most modern lenses stop for the actual element is beyond infinity.  So if you keep turning it a while and get to the point where it isn't changing, then you should go back a little to get to infinity focus.

Not sure how things could be going wrong for closer focus though, it is not readjusted between when you see it and when you take the photo... Unless you are focusing manually but in an auto more and are releasing the shutter half press in between so a new focus action is triggered as you go to take the photo.

I further tested the lens today and now I am even more puzzled. If I set the AF points to Auto, it seems that the lens is less prone to missing AF, but if I set it to anything else, it clearly back-focuses. At 2.8, my ears are in focus instead of my eyes.

I tested the lens on both my NX300 and NX1000 and it behaves the same.

I would really like to downgrade the lens firmware to 1.00 to see if that makes the difference, but I can't find it anywhere.