rcg530
Well-Known Member
- Joined
- Jan 23, 2021
- Messages
- 1,515
- Reaction score
- 2,557
- Location
- California
- Country
- United States
- Dash Cam
- BlackVue, Thinkware, VIOFO, Vantrue, Blueskysea, FineVu
In September 2021, Pittasoft sent me a DR900X-2CH Plus dash cam to review. A month or so after the review, I retrieved video files from the microSD card for comparison with video from another dash cam that I was reviewing. I noticed that the front and rear video from the DR900X-2CH Plus camera had different exposure levels causing the video from the rear camera to be much darker than the video from the front camera in similar lighting situations. I reported the issue to Pittasoft and after trying a couple different DR900X-2CH Plus cameras (front and rear) it appeared it was not a hardware issue.
The X Plus series firmwares no longer allow the user to configure the camera exposure levels. It's a firmware based decision on how to adjust the exposure level of the cameras for the lighting conditions.
Pittasoft sent me a DR750X-2CH Plus dash cam to see if the same issue occurred with that dash cam. The rear video from the DR750X-2CH Plus dash cam was darker than the front camera in a variety of lighting situations. In the DR750X-2CH Plus case, the same image sensor is used in the front and rear cameras (Sony STARVIS IMX327). The expectation was that the front video should be slightly darker than the rear video since the DR750X-2CH Plus front camera captured video at 60 fps vs the 30 fps for the rear camera with the same image sensor when both are exposed to similar lighting conditions.
The test setup was modified to have the front and rear dash cameras on the same window in my car (front windshield) to make sure both cameras were run with the same lighting conditions. The rear camera continued to record darker video than the front camera. I moved the DR750X-2CH Plus dash cam to another vehicle to make sure the issue was not vehicle / glass in the vehicle specific. None of my vehicles have any tint installed. The video from the test in the second vehicle was the same as the first vehicle - darker video from the rear camera.
Pittasoft tested another DR750X-2CH Plus dash cam in their office before sending it to me for testing. Their testing did not show any or much of a difference in the video brightness/exposure level. I installed the second DR750X-2CH Plus dash cam in my vehicle and the rear camera again captured darker video than the front camera in many situations.
Recently, I started reviewing the DR750X-3CH Plus dash camera that Pittasoft sent to me. The 3-channel configuration has the additional USB connected 720p 30 fps interior camera, the same rear camera and similar front camera (different firmware than 2-channel). The front camera in the 3-channel configuration records the front video at about 67% of the bitrate of the 2-channel front camera to allow the processor to handle the video from the interior camera. The end result is that the rear camera video is still darker than the front camera video.
The DR900X Plus, DR750X-2CH Plus and DR750X-3CH Plus all have the same rear camera (model RC110F) and all of the dash cameras that I've tested so far that use that rear camera have this issue of creating darker rear video in many situations.
(pic of RC110F rear camera)
For the past several months, I've been working with Pittasoft to try and track down what the root cause is for this issue. The issue best presents itself when the sky has clouds present that cover the sun to some degree. The front camera will leave the sky/clouds/sun somewhat overexposed to record the ground level objects at a decent exposure level. The rear camera adjusts the exposure level to the point of making the sky/clouds/sun not overexposed thus resulting in the ground level objects being underexposed and sometimes too dark to be useful.
My original DR900X-2CH Plus installation required the firmware setting of "Rear Camera Orientation" to be set to "Rotate video 180°" because the rear coaxial video cable length required me to install the rear camera rotated 180 degrees. I've continued that in most of my testing, but I have configured some of my test configurations to not have the rear camera rotated 180 degrees to see of that and/or the firmware setting to rotate the video caused the issue. It does not seem to matter which way the rear camera is installed (rotated or not). I've also gone through several aiming changes of the rear camera to make sure it isn't pointed too much towards the sky or ground. The vertical level adjustment has not significantly impacted the exposure level of the rear camera.
DR750X-2CH Plus (front / rear - both on front windshield) - Left = Front / Right = Rear
The next examples are from the DR750X-3CH Plus with front and rear cameras on the front windshield.
You can see a somewhat darker rear camera image (right side) than the front (left side) with clear / sunny skies.
The next example is with the "perfect" lighting conditions to show the greatest difference in the exposure levels of the front / rear cameras:
I will update this thread when more info becomes available for this issue.
The X Plus series firmwares no longer allow the user to configure the camera exposure levels. It's a firmware based decision on how to adjust the exposure level of the cameras for the lighting conditions.
Pittasoft sent me a DR750X-2CH Plus dash cam to see if the same issue occurred with that dash cam. The rear video from the DR750X-2CH Plus dash cam was darker than the front camera in a variety of lighting situations. In the DR750X-2CH Plus case, the same image sensor is used in the front and rear cameras (Sony STARVIS IMX327). The expectation was that the front video should be slightly darker than the rear video since the DR750X-2CH Plus front camera captured video at 60 fps vs the 30 fps for the rear camera with the same image sensor when both are exposed to similar lighting conditions.
The test setup was modified to have the front and rear dash cameras on the same window in my car (front windshield) to make sure both cameras were run with the same lighting conditions. The rear camera continued to record darker video than the front camera. I moved the DR750X-2CH Plus dash cam to another vehicle to make sure the issue was not vehicle / glass in the vehicle specific. None of my vehicles have any tint installed. The video from the test in the second vehicle was the same as the first vehicle - darker video from the rear camera.
Pittasoft tested another DR750X-2CH Plus dash cam in their office before sending it to me for testing. Their testing did not show any or much of a difference in the video brightness/exposure level. I installed the second DR750X-2CH Plus dash cam in my vehicle and the rear camera again captured darker video than the front camera in many situations.
Recently, I started reviewing the DR750X-3CH Plus dash camera that Pittasoft sent to me. The 3-channel configuration has the additional USB connected 720p 30 fps interior camera, the same rear camera and similar front camera (different firmware than 2-channel). The front camera in the 3-channel configuration records the front video at about 67% of the bitrate of the 2-channel front camera to allow the processor to handle the video from the interior camera. The end result is that the rear camera video is still darker than the front camera video.
The DR900X Plus, DR750X-2CH Plus and DR750X-3CH Plus all have the same rear camera (model RC110F) and all of the dash cameras that I've tested so far that use that rear camera have this issue of creating darker rear video in many situations.
(pic of RC110F rear camera)
For the past several months, I've been working with Pittasoft to try and track down what the root cause is for this issue. The issue best presents itself when the sky has clouds present that cover the sun to some degree. The front camera will leave the sky/clouds/sun somewhat overexposed to record the ground level objects at a decent exposure level. The rear camera adjusts the exposure level to the point of making the sky/clouds/sun not overexposed thus resulting in the ground level objects being underexposed and sometimes too dark to be useful.
My original DR900X-2CH Plus installation required the firmware setting of "Rear Camera Orientation" to be set to "Rotate video 180°" because the rear coaxial video cable length required me to install the rear camera rotated 180 degrees. I've continued that in most of my testing, but I have configured some of my test configurations to not have the rear camera rotated 180 degrees to see of that and/or the firmware setting to rotate the video caused the issue. It does not seem to matter which way the rear camera is installed (rotated or not). I've also gone through several aiming changes of the rear camera to make sure it isn't pointed too much towards the sky or ground. The vertical level adjustment has not significantly impacted the exposure level of the rear camera.
DR750X-2CH Plus (front / rear - both on front windshield) - Left = Front / Right = Rear
The next examples are from the DR750X-3CH Plus with front and rear cameras on the front windshield.
You can see a somewhat darker rear camera image (right side) than the front (left side) with clear / sunny skies.
The next example is with the "perfect" lighting conditions to show the greatest difference in the exposure levels of the front / rear cameras:
I will update this thread when more info becomes available for this issue.