Rokinon 8mm infinity problem

I recently purchased this lens from b&h, After doing some test shots i found it to not be very sharp beyond 6ft. I know alot of people have had calibration issue's with this lens and i would be willing to try to recalibrate mine the problem is i cant seem to find sharpness at infinity at any setting on the focus ring. Has anyone else had this problem? Also my lens seems to have a different focus scale ring than any samyang/rokinon lens i have ever seen, it goes straight from 5ft to an L mark before the infinity symbol it does not have a 10ft mark.

Welcome to POTN. I've read reports of bad copies of this one, with focus problems being cited. Check the screw under the rubber focus ring and make sure it's tight.

Does stopping down help?

No stopping down doesn't seem to make things any sharper. I did try a friends pro optic 8mm today and his was definitely sharper at infinity.

I've found that mine is pretty average until you get to F8.

Setting the focus ring to... anywhere doesnt really make a difference on mine as the depth of field is so massive anyway.

The lens definitely needs focus calibration. As it is normally used stopped down (f/8 is the best), and has huge DoF, you basically only need to find the smallest distance focus ring position at f/8 when infinity is still in focus (hyperfocal distance), and leave it there. Once calibrated, this lens is very sharp.

pulsar123 wrote in post #15341415
The lens definitely needs focus calibration. As it is normally used stopped down (f/8 is the best), and has huge DoF, you basically only need to find the smallest distance focus ring position at f/8 when infinity is still in focus (hyperfocal distance), and leave it there. Once calibrated, this lens is very sharp.

how do you calibrate it? mine is useless at f/3.5, nothing is sharp and halo around high contrast objects. stopping down to 5.6 does help.

I feel that infinity on my lens is just past where the lens stops turning. I also noticed that the inner barrel of the lens retracts as the lens gets closer to infinity which makes me wonder for people with a good copy does your lens hood touch the part of the lens with the gold ring when set to infinity?

On my 14mm the focus scale is off a bit too... But with so much DOF it is a non-issue. I just shoot hyperfocal distances and never have any problem.

f/8 and 1m...

f/5.6 and 1.25m...

Otherwise I use live-view to focus at f/2.8 or f/4 generally. Never had a problem!