DS-2CD2185FWD-IS 8MP image 'spotting' in IR mode [SOLVED]

[xbmcnut]

Anyone else seen this? I have other 4MP Hik cameras that look just fine at night but two of this model with 2.8mm lenses have unusable night-time images. I suspect the 4mm version of the same camera does not have this issue from what I've seen on YouTube? If I back off the IR output a bit it does improve but not enough to make these viable. It is a shame, as the day image is simply stunning. And yes, the dome is clean.

 

[biggen]

You say it’s clean but what about the Inside of the dome. Ir bounce back is always a problem with dome cameras.

 

[xbmcnut]

You say it’s clean but what about the Inside of the dome. Ir bounce back is always a problem with dome cameras.

Yep, polished the dome inside and out.

 

[Securame]

That column in the middle bouncing the IR surely does not help, no matter if you use 4MP/8MP or 2.8/4mm.

 

[looney2ns]

Anyone else seen this? I have other 4MP Hik cameras that look just fine at night but two of this model with 2.8mm lenses have unusable night-time images. I suspect the 4mm version of the same camera does not have this issue from what I've seen on YouTube? If I back off the IR output a bit it does improve but not enough to make these viable. It is a shame, as the day image is simply stunning. And yes, the dome is clean.

Light is bouncing back from that column. Causing the reflection in the dome and messing with the cams exposure.

 

[xbmcnut]

Turns out I had two issues. The previous installer had left a small barely visible smudge on the lens itself but more importantly, I've noted today that the 3 x hidden IR LED's in these G1 platform cameras must always remain above the glass bubble line. If you have the IR LED's at the bottom, one LED gets hidden and reflects inside the dome, causing my issue. Even if you have them above and need to rotate the camera to align your image, try and make sure no LED's drop below the glass line. If needs be, use the electronic image flip to fix things up.

 

[xbmcnut]

Today, I have categorically proven that the location of the three IR LED's in the G1 series Hikvision cameras makes a huge difference to the likelihood of image spotting and to the contrast of the image. Take a look at my before and after shots below.

 

[alastairstevenson]

Take a look at my before and after shots below.

Certainly a useful improvement.
But I'd suggest that the original problem is only indirectly caused by the orientation of the LEDs.
The underlying cause is likely to be that the IR is reflecting off a near surface back to the dome and refracting in, and that changing the orientation is simply altering the geometry of the reflection.
It's a common problem with domes when they are mounted in that type of location that has reflective surfaces in front of the plane of the camera.

If you haven't done it already - also check the image quality with the dome removed.
You might see an even better improvement in brightness and contrast.
Also worth trying as an experiment, if the image with no dome is further improved, would be to tape up some non-reflective paper on the surface above the camera.

 

[xbmcnut]

@alastairstevenson Thanks for your feedback but I'm going to have to disagree with you in this instance. While I've certainly seen reflective surfaces causing image degradation (not to this degree), I've again proved that rotating the IR LED's on these G1 series Hikvision cameras is all that is needed to significantly improve the night-time images.

The attached screenshots shows a colleagues installation before and after I got involved. The problematic camera was one of three in the installation with a 2.8mm lens and wall mounted. In my view, the wall mounting of these cameras encourages incorrect installation as by design, the cable egress hole in the casing is actually positioned at the top of the camera. Any decent installer would think to mechanically position this at the bottom of the camera (if not being used) to prevent water build up behind the camera mount. When you do this, you a forced to rotate the camera so that the IR LED arc is positioned downwards (incorrectly). As many home installers are not aware of the electronic flip feature, they just leave it at that and wonder why the night-time image is so spotty, myself included!

Without seeing the installation of the attached problematic camera, I bet the owner $50 that the IR LED’s would be upside-down and challenged him to simply rotate the camera 180 degrees, flip the image electronically and send me some before and after video. That is all that was done and you can see the outcome of that in the 2nd attachment. The results speak for themselves. You’ll notice that in this image, there is absolutely nothing that can reflect back into the camera.

From a dome design perspective, I think there are three factors that contribute to the problem.

1. Is more apparent with a wider lens
2. The smaller dome size in the newer cameras
3. Wall mounting encourages an upside-down install

When ceiling mounting the camera, it’s a 50/50 lottery. I strongly believe that everyone should be made aware of this issue with a sticky post about installation tips that will lead to the best image outcome but I’ll leave that in your hands.