Hey
@Maxpilot I'll chip-in with the info I've gathered regarding this exact "situation"?
I have a February 2017 Model S that came with Autopilot 2.0 hardware from the factory, (so no Dashcam and Sentry recordings).
When I had the Autopilot 3.0 (FSD) computer upgrade done to my car, my Model S gained the ability to record video to a USB drive. That's when I saw that all of my videos had the black bar at the bottom.
There is an area at the bottom of the video that is unfocused.
That black bar visible at the bottom of all front facing Dashcam and Sentry videos is the TRIPLE CAM GLARE SHIELD as
@Resist mentioned:
it appears that the camera is either; mounted incorrectly in the X axis
Since my Model S had the Autopilot 2.0 (Red Clear Clear Clear (
RCCC) filter cameras from the factory, I decided to upgrade all 8 of them to Autopilot 2.5/3.0 (Red Clear Clear Blue (
RCCB) filter cameras, in order to gain a bit of color to the videos that my Model S recorded.
While I was swapping the front triple cam I noticed the camera was held by a silver metal mounting plate, which gave the front triple cam its pitch angle, (and also holds the rear view mirror in place). You can see the mounting plate
in this video.
Knowing this and HATING

the black bar on all of my forward facing videos, I checked Tesla's
EPC and discovered that Tesla sells 3 Triple Cam Rear View Mirror Mounting Plates, which can change the pitch angle by: UP 2.33 DEG, UP 4 DEG and DOWN 1.2 DEG.
So I went ahead and contacted my local Service Center and ordered the UP 2.33 DEG mounting plate (1126328-00-A), since I figured 2.33º was enough to clear the Glare Shield and remove the black bar it creates on all front facing videos.
Once the part arrived, I installed it and went for a drive. Oh boy what a mess that caused!
Since the moment I placed my foot on the brake pedal in order to shift into Drive, my car threw a "Autopilot camera unavailable, Features may be restored on next drive" error.
I took the car for a quick drive around the block, and my Model S was not able to see lane markings, signs and other cars in front. I just had a blank Instrument Cluster with my Model S in the middle. Once I got back home, I checked the Dashcam recordings and the front triple cam was able to record the full drive and the video clearly showed cars and stop signs and lane lines, but the Autopilot computer was not able to interpret them. The biggest finding was that the video didn't have the black bar at the bottom. The 2.33º pitch up was able to clear the Glare Shield and the video was beautiful and "clean".

Granted, the video was now a bit upward, as now I could see some more clouds and a bit less licence plates from the cars in front.
I figured the Autopilot 3.0 (FSD) computer just needed to "get used to" the new
framing of the video. So I clicked on Controls and went to the Service menu and clicked "Clear Camera Calibration". I went on another quick spin around the block, but the cameras weren't able to calibrate past 11%. I decided maybe the neighborhood roads were the problem, so I got on the highway and drove 240 miles. But I still couldn't get past the 11% calibration mark.
Long story short, my Model S would not finish the calibration process no matter how many miles I drove. So after a few days, I scheduled an appointment with my local Service Center. I didn't tell them I changed the pitch on the triple front camera, but I guess they suspected since they were the ones who sold me the part to do so. They kept my car for 2 days, as they couldn't figure out why the car was unable to calibrate the cameras. Eventually at the end of day 2, I got a notification on the app that my car was ready. When I got there, the Service Manager told me they tried to calibrate the cameras using the method done by the factory using static targets:
but that didn't work either, as their
Garage diagnostic software was telling them the pitch in the triple front facing camera needed an adjustment DOWN!!! He added that they changed the front facing camera mounting plate to the stock mounting plate (1098491-00-C) and everything went back to normal. Apparently a 2.33º change in pitch is not too much for the Narrow and Main cameras, but it's a huge change for the Wide angle camera. They didn't charge me a dime for all this, but as you guessed, my Model S is back to its Dashcam an Sentry black bar videos again.
I just noticed this on my Model 3 too!
I told the Service Manager that all the videos my Model S recorded had the Glare Shield at the bottom, but I had previously seen some Model 3 and Model Y videos that had a smaller intrusion from the Glare Shield and some that had none. He said that at some stage of the Model 3 production, Tesla changed its windshield provider (for all Model S, 3 and Y), and thus changed the windshield angle, material and coating as well, (I think that's why some have the rainbow effect and some don't). So they had to update the Glare Shield for all Autopilot equipped vehicles with a new revision part. I believe there's even a
Service Bulletin for this which states that Service Centers must: "...Inspect the part number of the glare shield, if the glare shield is revision 99-C, revision D or later, discard any washers and reinstall the glare shield (refer to Service Manual procedure 15052502), otherwise, install the newest glare shield revision available".
I've seen other dash cam video that didn't have this issue
I've seen several YouTube videos from Model 3's and Y's Sentry and Dashcam footage and I'm a big fan of the
Wham Baam Teslacam YouTube channel and I have noticed a varying degree of Glare Shield intrusion from video to video and from Model to Model, but the common denominator is that Model S' have the worst of all. My wife has a Raven Model X, which also has the Glare Shield intrusion, but it's quite small and barely visible. My dad has a 2016 Signature Model X and its Glare Shield is much more visible than my wife's Model X, but still not as terrible as my Model S.
Tesla service said it is normal on Model S. They say they went out and looked at new cars and they say the same weird area appeared at the bottom.
I find it quite strange that your Model S being so much newer than mine, still has this issue. I'm more than certain that your Model S has the newer revision "G" or "H" Glare Shield which should (by my non-Tesla expert standards) at least reduce the size of the black bar at the bottom. We just need to wait until this Thursday for some owners to take possession of their new Model S', in order to determine if this is still an issue with the new Palladium platform, considering they have the interior facing camera in the rear view mirror housing and assembly and therefore maybe they have a new Glare Shield or a new triple cam mounting pitch angle.
Sorry for the long post, but I just wanted to share my experience regarding this subject, which as with ALL things Tesla... in the end, it all comes down to: "It's within spec".