I am definitely no expert like some folks on here but I have been happy with this camera model. Definitely varifocal and the image is good day and night. Performs well with strong IR (I belive the 80m quote). Did extensive testing all around my house both day and night. Recorded using dahua nvr and smart pss. If my wife didn't require me to buy turrets I would install these everywhere except for the 1 starlight I just ordered.
Just order one and try it for yourself using smart pss to record and see if it meets your needs. Omni Security on eBay has US stock so returns are easy (sent back a dome I tested last week - ick). You should also be able to update firmware with the help of these forums even though I haven't yet.
I will likely be using 1 each of these zoomed out to about 7mm for our 2 gates to our backyard. I blasted my recordings after putting in a new 4tb surveillance drive and a ssd for Windows or I would show samples. Definitely not a starlight but for around $75 I think it is a good value. Definitely not perfect but better than many others out there. Search this forum for that model #.