Video quality well below expectations - normal or return?

[xamoel]

Hi guys,

I finally jumped the fence and bought my first dashcam, the DR900S-2CH, even after reading of its numerous problems.
At least I expected a great daytime video quality, but as it seems it doesn't deliver quite what I expected.

Settings are 4K@30 Extreme, 1080@30 for rear, with H264 codec for less heat development and strain for the processor.

See attached screenshots (frame grabs extracted with video lan player), I cannot decipher a licence plate 10m in front of me.
Also the rear cam doesn't quite fit my description of good 1080p. I have several Hikvision surveillance cams, cheap ones for 90 bucks, and they provide way better detail at 1080p than the Blackvue.

Could someone with more experience chime in and tell me if that's normal, or a hardware problem?

Thank you so much!

 

[jokiin]

you won't see license plates at the distances you are in these screenshots

 

[SteveFL]

From my experience with the DR900S as well as my DR650S and DR750LW, not to mention other forms of image capturing devices, your image quality will suffer from the following:

1. Shooting through glass.
2. Shooting through glass that is not 110% pristine clean.
3. Glass that possess small imperfections or a protective film, such as a windshield / windscreen.
4. A combination of #2 and #3 above.
5. Light hitting the windshield / windscreen as such an angle that it can distort or slightly blur the image that the camera is capturing.
6. A camera lens that may have some dirt or oil, (body) on it. The latter can easily happen during the mounting of the camera without any real knowledge of it happening.
7. There could be a temperature variance that can cause the lens to every so slightly expand during extreme heat or contract during extreme cold. The first issue happens to me in the Summer, especially living in Florida, USA.
8. Lastly, it could be a combination of all of the above.

And then of course, there could be an issue with the camera. Try taking some images without shooting through glass, (and make sure the lens is 100% clean) to compare images. Pick a location, subject and time of day. Take images of the subject through the windscreen / windshield and then not behind the glass; compare the images and see how they differ.

By the way, what part of Germany do you live? I have lived in Stuttgart and Heidelberg previously.

 

[xamoel]

I'm located in Munich!
Surely the windshield could be cleaner, but how else am I supposed to mount the cam, if not behind the windshield

@jokiin in the first 3 images I agree, but the last one is quite close, I mean that is too far for a 4K cam?

 

[jokiin]

Too far away

 

[c4rc4m]

It's a very wide angle lens (162 degrees) which means the pixels are spread over a large area. It shouldn't be too much of a concern because any vehicle that hits you will come closer before it does!

Your alternative is a 2nd camera with a zoom lens - see the mobius telephoto thread.

As for wide angle, I've long thought somewhere between 90-120 degrees was more than enough.

 

[c4rc4m]

Here, try inputting figures into here:

https://calculator.ipvm.com

At 162 degrees FOV, you end up with just 10PPF at 30ft. Picture is just a blur - that's what you get when you zoom in on the plate afterwards.

Now reduce the angle to 120 degrees. You end up with 37ppf and a plate thats readable if a bit blurry. It's not until you drop to 80 degrees that you get a decent image and 30-40 degrees until you get something approaching very good.

What's the point here? Contrary to current marketing for dashcams, wide angle lenses are actually an evil and the wider you go, the worse the quality of the picture gets for detail retrieval. The flip side of course is you capture more to the side of the car as well as in front. (You can find a few rants of mine on here from more than a year ago about wide angle lenses and their negative effects on detail retrieval).

Ultimately it's going to be a compromise, and your choices here are 2 fold:

1. Choose a dashcam with a narrower lens, as I said above, personally I could live with anything from 90-120 degrees

2. Or get a 2nd dashcam with the ability to change lenses, eg the Mobius and fit either a fixed or zoomable replacement lens so you can have a FOV of say 30-40 degrees to retreive detail at range, without losing the wider view provided by the 1st dashcam.

 

[xamoel]

So basically this quality is the best it gets for the DR900S?
Because the pictures from here: https://dashcamtalk.com/forum/threads/dr900s-2ch-initial-impressions.33902/
look way better regarding readibility of the number plates?

 

[Nigel]

So basically this quality is the best it gets for the DR900S?
Because the pictures from here: https://dashcamtalk.com/forum/threads/dr900s-2ch-initial-impressions.33902/
look way better regarding readibility of the number plates?

The photos you posted are at 1080 resolution, not 4K...

 

[xamoel]

Then the forum must have resized them, only the second one is from the rear with 1080p, rest is 4k Extreme.

Just tried it out, uploaded 4k, when I download it it's a third the size. Still the quality isn't better in the original file.

 

[c4rc4m]

So basically this quality is the best it gets for the DR900S?
Because the pictures from here: https://dashcamtalk.com/forum/threads/dr900s-2ch-initial-impressions.33902/
look way better regarding readibility of the number plates?

The top picture set in post #1 using Extreme Quality is less than the 30 feet in this current thread to the vehicles in front and the enlargements at the top of the picture showing the plates show extreme blur to the point where they're barely readable. I'd actually estimate the distance to be around 15 ft. So not seeing the quality difference you're claiming from the 1st post.