I received the
16mm lens I ordered off AliExpress yesterday. Today I fitted it to one of my 2.8mm Hikvision DS-2CD2342WD-I 4MP cameras. The glue was a major PITA to scrape off the factory lens and I ended up wrapping the lens in some paper and gingerly grabbing the lens with some pliers to gently release it. The new lens was a loose fit, so I used the Teflon plumbing tape idea (as per the video) to pad it out and prevent unwanted rotation.
Focusing was relatively easy, but I quickly found out how a long length f2.0 lens limits your depth of field for focus. I ended up settling on distant objects being slightly out of focus in order to improve the closer (ie. 3-4m distance) focus.
I've got to say I'm highly impressed with the quality of the lens (random purchase/ paid full price/ no association with the seller.) The image quality is superb and I don't think a genuine Hikvision lens would be any better. I haven't tried it out at night yet, so the lens reach may well outdo the capabilities of built in IR.
There were no mods required for the 16mm lens to fit in the DS-2CD2342WD-I. It appears to possibly sit closer to the camera body's glass but doesn't touch. (Spacing the lens module further back should be possible if there are minor issues with the lens touching the glass.)
Below are the specs for the lens (for anyone looking at doing the same mod.) The same place sells other 5MP lens with similar specs that should also fit. I've ordered a couple of other lengths to try out- at around $10 ea delivered I figured why not.