WDR on or off

[SuperCurro]

Hi

I made some testing during the night and yes, the WDR takes three frames and join in one, during the day no problem as the shutter speed is very high and the result is very good, during the night it is a problem as the shutter speed is around 1/60 to be able to give 30 fps, with 1/90 and movement the imagen is blurry but static is no problem.


This is two images blurry one over the other, without WDR it is also blurry, but you dont have two exposures and then you don't have a double image. (blurry but not triple?).


I have to make more tests because I am not sure if the camera will go below 1/90 to 1/30 to get more light, but then we will have also a blurry image but not 3 of them on top of each other. Not clear if you can read better the plate numbers.

What is clear is that during the day with WDR it is better, you don't have to post-process and there is less noise, artefacts and blocks in the shadows.
In any case, if you don't use WDR you will need to set anyways EV -1.0 front and EV -0.3 rear, if not you will lose the highlights that can not be recovered.

Please post your experience.

edit: I have tested several EV and yes, you can get almost the same result in the front camera (not but near) but in the rear camera WDR is far away better than NO WDR, it is impossible to be close. Let see tonight, then depends a lot how much you drive during the night. During the day the clear winner is WDR.

 

[Nigel]

I made some testing during the night and yes, the WDR takes three frames and join in one,

My experience of VIOFO cameras is that normal mode is single exposure, WDR is single exposure, and HDR is double exposure. I don’t think that three exposures is possible on current hardware.

If you are actually seeing three exposures per frame then it is probably because the light source is LED based and is sending out three pulses of light during the exposure.

, if you don't use WDR you will need to set anyways EV -1.0 front and EV -0.3 rear, if not you will lose the highlights that can not be recovered

-1 EV may give you good exposure for the highlights, but it will lose some detail in the shadows. Generally 0EV should be about the best compromise for most people when using the dashcam for evidence, -1 maybe a good choice for movie making.

 

[SuperCurro]

Thanks for your response.

Yes, I have made an experiment, Front camera is left, the rear camera is right, no WDR is up and WDR is down... It is clear that WDR is just a different way to process the data from the sensor because the exposure is the same. Front is -1.0EV and rear -0.3 EV



About the EV compensation to me is clear, if the image is burned you can not recover, if it is dark you can recover... the Front Camera with WDR and +0.0 EV is too bright and it burns too much, on top of it you are far away from the black at the dark side. The rear camera it is close to the 0.0 EV, but I prefer -0.3 EV.

In any case to get evidence the main problem is going to be the motion blur due to low light. I am going to finish my investigation here, later with more km and examples I will do fine tuning.

Front Camera WDR -1.0 EV
Rear Camera WDR -0.3 EV

 

[raab]

Quick wdr off on comparison on a bright day, with WDR on its noticeably noisier but it helps with the whites.. with it off the white picket fence blurs into one.. this is with the front at -1.0 EV

WDR off:


WDR on:

 

[Nigel]

Quick wdr off on comparison on a bright day, with WDR on its noticeably noisier but it helps with the whites.. with it off the white picket fence blurs into one.. this is with the front at -1.0 EV

That is what WDR is supposed to do

Can you give the EV settings for each image please? It is not clear from your description if you changed the EV setting between WDR on and off...

 

[raab]

WDR off was EV 0
WDR on was EV -1.0

 

[737mechanic]

I have two Hikvision security cameras with WDR and a VIOFO A129 with WDR both security cameras have an auto function for WDR so when it determines it helps it will automatically switch on WDR and when not needed it will switch it off. I wish the A129 had this option because most of the footage I get looks much better with WDR off. In fact, I have experimented with my security cameras over the years with WDR completely on and completely off and 90 percent of the time the scene looks better with WDR off. Only when you have a blown-out highlight does WDR need to be on and most of the time in my case that isn't an issue.