The focus worked fine initially. After a year and half it does ...
357328
Image quality is average. The focus worked fine initially. After a year and half it does not focus correctly. I have another canon point and shoot (A630) and it does not have any problem even after 6 years and 10000+ shots. The image shows a lot of noise and grain from ISO 400. Color does not look good in most settings. The auto mode usually overexposes the images by 2/3 or 1/3 stop. Face recognition worked well and the size was perfect for regular carry. It gets 3 star for image quality compared with a similarly priced competitors product and canon A630.
3388229
Update:
Tamron fixed the lens and it appears to be working. Only time will tell if the fix will last. Image quality is back to being quite good.

Original review:
Sadly, this lens failed when I needed it most: while on vacation. After using it without issue for several months, I noticed that the autofocus would suddenly stop working. Toggling the AF/MF button would not help, but unmounting and re-mounting the lens to my Nikon camera worked occasionally. The issue is intermittent, but seems to crop up at the worst possible times.
Still waiting to hear back from Tamron regarding how much they will charge me to fix the defective lens they sold me.
If you can overlook the fact that the lens broke after four months of light and sporadic use, you will see image quality is pretty good. That is if you can get anything in focus.
4367281
Nice because of its price and large aperture but it has problems focusing, and in the first times produced an error and did not take the photo.
3681056
This product stopped working with no fix after a year and a half. The screen began to flicker and now it pixellates uncontrollably. Too bad. When it worked, it was fine but it doesn't matter. It's dead.
3853324
It has worked for about a year, but now the springs (Ones that push it back up after one clicks) are not as rigid, and as a result it double or triple clicks, all the time. It is unusable at this point. But for the price it worked well for a year or so.
2218143
I have to admit that I like it a lot when we first received it. Not so heavy, easy to carry, and clear view of sky at night. But after a few months of light use, one of the knobs that adjusts the focus of eye lens went cracked, and now the lens cannot adjust focus. Poor quality.
111440
Purchased on February 18th to monitor the front of my house to replace a Hikvision dome.  Install was pretty straightforward. As others have said, picture quality and focus during daytime was excellent. Nighttime quality and focus leads a lot to be besides. Moving objects appear as blurs. I have verified this issue is present on recorded clips on the unit and also on Blue Iris. Kind of defeats the purpose. Recently experienced two Noreasters here in the East coast and camera decided to stop working. Camera build seemed pretty sturdy and seals seemed tight, so not sure what happened. Sending back to Amazon for a refund.
1512104
I used this for about a year before it completely died.  Months before it totally died, it occasionally didn't work when I first plugged it in.  I then had to plug it back in/out many times or turn the transmitter at a different angle to get it to turn on.  Overall, the transmitted does what it's supposed to do, until it starts to die out.  I had the same issue with the previous radio transmitter I bought, so it's not that big of a surprise.
2865268
Fully functional, for a while.  Now if it turns out your plastic lens that this plugs into is fading, the red bulb is not a real "fix" and if you look over time the red coating will "melt" away due to incandescent heat.
3524943
Worked fine for a little over a year (albeit, it eats up batteries), then the shutter release stopped working entirely. No damage, it just stopped working. Unfortunately, I didn't get an extended warranty. Not recommended.
218840
The baby monitor quite working after a year and a half of use...I can't get the camera to connect to the monitor.
1762480
I was happy with this at first but after a year of steady use i really am unhappy.  Its slow between shots, low lighting is not good. lens error is showing up all the time now and some times it just won't work.  always need my second battery close by as well.  don't buy it
4255676
When my warranty was due to expire, I sent it in for a cleaning and recalibraions of the focus system.
942744
At first I loved it, but over time (6 months) the picture quality began to degrade, vignetting on the edges and a lack of sharp focus in all but the best lighting, I finally pulled it off and went back to my old lenses, too bad because it had a perfect range to be a single use lens and save me carrying around others.
2676669
For the price it worked for a while and after a year or so had enough wear to toss it.
3487668
Worked great for about a year and a half.  The video works well.  HOWEVER.. The touch screen has failed rendering it completely unusable.  From the forums it appears that many are failing the same way (It appears that the touchscreen wasn't designed for the heat of a windshield).  There is no acknowledgement of the problem from BlackVue, and they have taken down their pages even acknowledging that this was their product.
4594690
It is ok at best, but for the price it is worth it. Slow to focus and only the center focus point will work.