orangefish

Hello, I have a Samsung GV BCC825 bullet camera which has 24 LEDs around the camera lens. How do I find out what exact LEDs are these? The cameras spec sheet is: http://products.isc365.com/AVCat/images/documents/pdfs/Samsung%20GV-BCC825%20Datasheet.pdf I know they are 850 nm IR LEDs and they appear to be of 4.8 or 5 mm in diameter and they are clear in color. I have attached a pic of the front of the camera with the glass cover removed. I am hoping the LEDs are one of the most common used in such cameras and so someone might already know what model they are. Otherwise, I might have try disassembling the front of the camera further to try to find out their part number myself. Thanks.

Hello, I am looking for information on the safety of NIR LEDs commonly used in consumer night cameras now a days. Any resource which describes this in detail? Or if anyone has insights into the safety factors compared to the distance between LEDs and eyes, that would be great too. Thanks.

Hello Pardon my ignorance, but I was wondering why do day/night cameras need a photo cell? If all it does is tell the camera whether it is dark or not, can this same function not be performed by the camera itself? The CCD is constant, the shutter speed is known, the aperture is known, it should not be difficult to find how much light is entering the lens and deduce bright/dark conditions by the camera circuitry (I think it is already making a judgment since it varies the shutter speed). Thanks in advance.

Hello everyone, I am trying to get familiar with a Samsung bullet camera. It has day/night modes which are controlled by a photocell. I have a couple of questions: 1. If I block the photo sensor with some tape, the camera's near IR LEDs turn on. Now if I turn the room lights off, I get a B/W video of the scene. But if I turn the lights ON, the video is not graycale anymore and has color. I am not clear why this is so. Don't the cameras work in B/W mode in night conditions? 2. The camera's specs list a "Day/night pass filter". What is that supposed to mean? Thanks, HS.

Hello everyone, I am looking for an IR filter (to cut visible wavelengths). The camera I want to use it on does not have a C or CS mount and the only way, as far as I see it at present, is to place a 48 mm diameter filter along with the glass covering the lens. So, what are recommended places from where I can order a 48 mm, 1 or 2 mm thick, IR filter (similar to Hoya R72, which all wavelengths shorter than 720 nm)? Thanks in advance.

Yes, that is what my understanding was. Plus, they are also used to avoid the slight blur caused by the longer wavelengths (near IR and longer) not focusing on the image plane where the visible wavelengths focus. So IR cut filters serve these two purposes. Regarding the exposure point the other poster raised, I am not sure that is correct. The exposure is calculated by the amount of light falling on the CCD. It should not matter if any filter decreases the amount of light passing through the lens, the exposure setting algo. should adapt accordingly. The only situation where any illumination reducing filter can affect the exposure is when the camera is already working in very low light environment and filter just decreases the light below the minimum threshold. Otherwise it should not really matter as fas the exposure is concerned. BTW, can somebody put up examples of a 'day scene' with and without the IR cut filter showing the color change? It would be really appreciated. Thanks.

Hello, I am trying out a bullet day/night camera (as I mentioned in my other posts). What I am trying is to block the photo sensor to force camera to work in night mode (with IR LEDs on). In this mode, if the surroundings are lit brightly, the camera shows a color image. However, if the surroundings are dark, the camera shows grayscale image. BTW, the camera does not appear to have a mechanical IR cut filter. So my questions is, while the photo sensor is covered and the camera is thinking it is night, how does it decide when to show a color image and when to show grayscale? I am thinking it might be programmed in the camera's firmware and the decision is made based on the illumination perceived by the CCD sensor. Thanks in advance. Regards.

Okay, I tested the camera by pointing a remote control to it. The brightness of remote control LED does not change with or without the little tape over the photo sensor of the bullet camera. I supposed then that the video camera has no IR block filter at all! Also, I cannot make out any mechanical clicking sound that I would expect with a mechanical filter (or are they *really* quite?). thanks.

Right, so it is the cost factor. Makes sense. Thanks guys, Regards.

I have this bullet camera (by GVI, GV-BCC825 ... sorry, not able to put URLs yet). Its specs say it has Day/Night near IR pass filter. What does that actually mean? They actually have a filter that lets through only visible and near IR wavelengths? It has 24 near IR LEDs, 850 nm, that work in dark conditions. I called up GVI to ask if the sensor of the camera is covered by a near IR filter during bright light conditions and uncovered during dark condition. The guy wasn't sure what I meant, he asked somebody and all he could say was the camera does not come with any filters. I am think he might be meaning that the camera does not have any filters mounted at the front. Also, I know that in general CCD cameras come with near IR cut filter (usual still and video cameras). These cameras have a thin near IR filter cut filter placed right on top of the CCD sensor. The security cameras which can work in dark conditions using near IR LEDs should not have this little filter, right? What is the industry practice regarding this? Thanks in advance. Regards. HS.