Help tweaking 4K-T

[biggen]

First thing I'd tackle is the white balance. Taht sodium lamp is terrible. Move white balance on night settings from Auto to whatever works best for you and removes that yellow colour cast.

I'd also suggest 120th is too slow a shutter. The woman is blurred and the street lamp should have plenty of light. I use a range with 250th (8ms) set as the maximum permittable. I'll post my rear yard camera settings later when I'm at my BI pc, as it works with only a 5w led for illumination.

One cure for blow out would be to lower the contrast a little. You may find 60 is just too strong in that situation.

PS I find the focual point on my 3.6's to be around 16 feet or so. They're very good at distance but not so good close up.

I already have the WB set to "Street Lamp" and that tamed some of the yellow. If I leave it set to "Auto" its even worse!

I can take a look at 1/250 tonight but that may give too dark of a picture though. I'll give it a try and see however.

 

[biggen]

Since I think I'm over the identify limit of this 3.6mm 4k-T, I'm tossing around the idea of about taking it down and putting up a 5442TM-AS in 6mm in it's place or the varifocal model of the 5442. The varifocal has 3x the focal range of the 4k-T.

I can use the 4K-T as an overview cam elsewhere. Hmm...

 

[bigredfish]

I recently did the same thing.
With the apparent limited close focus and depth of field, they seem better suited as overview cams unless (with the 3.6) your primary coverage area is from 10-20 ft.

 

[biggen]

I recently did the same thing.
With the apparent limited close focus and depth of field, they seem better suited as overview cams unless (with the 3.6) your primary coverage area is from 10-20 ft.

Yeah that's too bad as I love the image clarity and low lux.

 

[Perimeter]

And yet look how good the 6mm image is on the Hikvision camera on the first page of this thread. So it is doable.

Yes, if you are willing to take apart the camera and adjust the lens...

 

[Parley]

Yes, if you are willing to take apart the camera and adjust the lens...

Hivision has since fixed that problem. I have not had to that with the last bunch of cameras. Only the first ones out.

 

[biggen]

First thing I'd tackle is the white balance. Taht sodium lamp is terrible. Move white balance on night settings from Auto to whatever works best for you and removes that yellow colour cast.

I'd also suggest 120th is too slow a shutter. The woman is blurred and the street lamp should have plenty of light. I use a range with 250th (8ms) set as the maximum permittable. I'll post my rear yard camera settings later when I'm at my BI pc, as it works with only a 5w led for illumination.

One cure for blow out would be to lower the contrast a little. You may find 60 is just too strong in that situation.

PS I find the focual point on my 3.6's to be around 16 feet or so. They're very good at distance but not so good close up.

Can't go any faster than 1/120. I get horrible horizontal rolling bands from the flicker of that street lamp if I go faster than 1/120.

 

[wittaj]

Can't go any faster than 1/120. I get horrible horizontal rolling bands from the flicker of that street lamp if I go faster than 1/120.

Try odd increments in ms.

So 1/120 would be put in for the range as 8.33 to 8.33 as you want to keep it as a fixed shutter.

So try like 7.5 to 7.5 as an example so that you are not in the in/out phase of the light.

It will take some trial and error, but you should be able to find a shutter speed that doesn't cause it.

OR the issue is you simply don't have enough light to go past 1/120 shutter without the firmware going wonky. When I was testing my 4K/T I would hit a shutter speed that it would produce rolling band even with all incandescent light bulbs, so I know it wasn't the LED frequency wave issue.

 

[biggen]

Just tested and anything faster than 8ms results in rolling horizontal bands so you may be right that it’s firmware related.

 

[biggen]

Also just tested and anything slower than 1/60 also induces rolling bands until I hit 1/30 and it stops again so I do think it’s flicker related to the street lamp.

 

[Parley]

Just tested and anything faster than 8ms results in rolling horizontal bands so you may be right that it’s firmware related.

Under exposure/anti-flicker see if you have it set at 60HZ. That has helped me with fast shutter speeds with what you are describing.

 

[biggen]

Under exposure/anti-flicker see if you have it set at 60HZ. That has helped me with fast shutter speeds with what you are describing.

All that does it force you into shutter speeds that are factors of 120. So 1/120, 1/60, 1/30, etc…

 

[Parley]

All that does it force you into shutter speeds that are factors of 120. So 1/120, 1/60, 1/30, etc…

I am not saying that this is your problem, but I was "assuming" the street lights were causing your problem and the reason for my post.

"What caused this flickering effect? Blame the hertz! (not really). The hertz is a unit of frequency that defines cycles per second. So, if the lighting in the school is running at 60Hz, this is just a fancy way of saying that the electricity flowing into the fluorescent lighting is cycling ON-OFF 60 times per second. While the human eye does not detect it, there is a subtle dimming of the light during each of these ON-OFF cycles. It is this dimming that our camera is seeing, and recording."

 

[biggen]

I am not saying that this is your problem, but I was "assuming" the street lights were causing your problem and the reason for my post.

"What caused this flickering effect? Blame the hertz! (not really). The hertz is a unit of frequency that defines cycles per second. So, if the lighting in the school is running at 60Hz, this is just a fancy way of saying that the electricity flowing into the fluorescent lighting is cycling ON-OFF 60 times per second. While the human eye does not detect it, there is a subtle dimming of the light during each of these ON-OFF cycles. It is this dimming that our camera is seeing, and recording."

I think you are right in that it’s the street lamp. But when I set the camera to 60hz anti flicker, it only lets me choose from 6 shutter speeds (all factors of 120) up to a maximum speed of 1/120.

Need to have our HOA switch out the olds lamps for LEDs. The newer half of our neighborhood is getting these same street lamps installed but all with cool white LEDs.

 

[Parley]

I think you are right in that it’s the street lamp. But when I set the camera to 60hz anti flicker, it only lets me choose from 6 shutter speeds (all factors of 120) up to a maximum speed of 1/120.

Need to have our HOA switch out the olds lamps for LEDs. The newer half of our neighborhood is getting these same street lamps installed but all with cool white LEDs.

I agree, the white LED street lights would be a big help with my cameras. I do not think they are coming anytime soon to my neighborhood. Now the tract behind my house which is the city of Garden Grove, they have the LED street lights. This only helps with one of my big PTZ cameras which is aimed in that direction. My other big PTZ camera which is aimed up the street in our tract, I have to set the anti-flicker to 60HZ to prevent the rolling lights.

 

[Perimeter]

If you use an exposure time faster than the flicker (for 60Hz this would be under 8.33 ms), you are taking pictures of a scene that will change in brightness between each frame. There is no way to avoid this.
I can observe street lights going brigther and darker slowly when I am at 6ms. The effect changes here in magnitude with 3D-NR, encoding and bandwidth.

 

[CCTVCam]

It won't help the flicker but may make it less obvious if you set the white balance away from auto and that dark orange as I mentioned above. For most people it's fine on auto. With those sodium lamps, I'd set night profile to whatever makes the scene appear white. You'll have to test to see which setting works. I can't remember if there's a custom option as my cameras are currently down so I haven't been in the interface for a while, but If custom is available and non of the presets work, try selecting custom and adjusting the colour temperature to match the scene.

 

[biggen]

It won't help the flicker but may make it less obvious if you set the white balance away from auto and that dark orange as I mentioned above. For most people it's fine on auto. With those sodium lamps, I'd set night profile to whatever makes the scene appear white. You'll have to test to see which setting works. I can't remember if there's a custom option as my cameras are currently down so I haven't been in the interface for a while, but If custom is available and non of the presets work, try selecting custom and adjusting the colour temperature to match the scene.

Check my post #41. It’s on “street lamp”. I haven’t used auto as it’s even yellower than street lamp.

Ive played with custom but can’t quite get it right.

 

[wittaj]

Based on my experiences with my 4K/T and helping others via DM and seeing how theirs reacts at night to differing light conditions, I believe the flicker is a byproduct of the the firmware once you reach the point of not having enough light for the shutter speed being ran.

I wouldn't call it a bug more than it is a limitation of the firmware by pushing it to the limit.

The firmware is written in such a way to provide bright images at higher shutter speeds than we have seen with other cameras, but when it gets pushed to the extreme, this is what is happening.

 

[biggen]

Based on my experiences with my 4K/T and helping others via DM and seeing how theirs reacts at night to differing light conditions, I believe the flicker is a byproduct of the the firmware once you reach the point of not having enough light for the shutter speed being ran.

I wouldn't call it a bug more than it is a limitation of the firmware by pushing it to the limit.

The firmware is written in such a way to provide bright images at higher shutter speeds than we have seen with other cameras, but when it gets pushed to the extreme, this is what is happening.

The thing that leads to be believe that isn't the case for my issue is that if I use any shutter speed at night that isn't a factor of 120, I get rolling bands. So that means even if I go slower than 1/120 like 1/100, I'll get rolling bands at 1/100. I have to stay at factors of 120 at night when that lamp is running to avoid the bands.

I have a varifocal 5442 coming from Andy soon. I'm going to put it up in place of this 4k-T. We will see if the rolling bands continue with that camera.