1/60 f5.6 iso6400 260mm
M 1/13 f5.3 iso6400 220mm
After seeing the issues mentioned by bros above, I did a quick test 10 mins ago. So this is a fresh test from the "oven".
I off my bedroom light, switched on my bedroom toilet light and closed the toilet door almost fully, allowing just a small ray of light through the door.
First pic shows how the ambient looks like.
Pic 2 after I adjusted the exposure.
Did the lens hunt? You bet it does, I nearly cannot see the subject through VF.
Can it lock focus? Yes it can as shown above. I used Manual exposure, AF, Spot metering, and lock AE/AF button after focus was locked before I recomposed and pressed the shutter. Focus was on the eye of the subject. I do not use AF assist light. Lens used is consumer lens 70-300 VR. AF-A Single mode, hand-held.
Bottom line is, I will not wanna shoot in that kind of environment. Was the pub as dark as what is shown in Pic 1? If it isn't, then I suggest to the affected bro to bring your camera to NSC for a check up.