CameraGimp

Your question is quite hard to answer as there are many different types of camera available and they serve different needs. It isn't fair to compare the features of a box camera with a mini dome for example. Each can be a quality camera in different ways. T It might be better to be more specific and ask what makes a quality low light camera, a quality general indoor camera or a quality low light minidome as each has it own needs. To get the ball rolling a quality camera should be reliable.

I'd suggest the reason the cameras go out of focus at night will be down to depth of field reducing as the lens iris opens. This is normal. You should always focus a camera with a motorized iris with the iris fully open. You can do this in two ways. Focus the camera at night or use put a filter over the lens to reduce the light reaching the lens and then focus the lens. A third method which I hesitate to recommend is to turn electronic iris on and then focus the lens. If you are lucky EI will cut in at a lower video level than the level that the lens is set to. If this is the case the lens will open fully and the EI will crank right up. One way to check this is to turn EI on, give it 10 seconds to settle and the lens to adjust then turn it off. If the picture whites out for a second then the iris was open. If you use this method it isn't in any of the text books but it can work. Don't forget to turn EI off after setting the focus or you'll waste that expensive lens.

Here is a not so brief overview of the different WDR technologies out there. In the beginning there was dark, then there was light, then they put both together in a shop doorway and Panasonic made the SuperD camera. That might sound dramatic but for a long time there was only SuperD that offered WDR. SuperD worked by taking two images where a normal camera would only take one. The two images would have different shutter speeds. The fast shutter speed image would capture the highlights well. The slower shutter speed image would capture the low lights well. The camera would make one WDR image using the best bits from the two images. Since then we have had SDII and SDIII but the basic theory is the same. It is called dual or two shot and it is now available from other manufacturers as well as Panasonic. This type of system gives the haze or halo effect when it is being pushed to the limit. A good way to show this is to stand in front of one in a strong backlight and rock from side to side. You should develop an angels halo around you. This happens at moving transitions between bright and dark. As the two shots happen at different points in time and you have moved between shots the camera can't produce a perfect picture from the two shots. It is more obvious the wider the dynamic range in the scene, or the more you push the camera to its limit. The other contender for WDR is Pixim DPS. This is in my mind a better way to do it but it does have it's drawbacks in other areas. It isn't going to be a good at low light and it doesn't have all the none WDR features that the Panasonic cameras come with. Pixim don't use a CCD. To read one pixel on a CCD you have to read them all. That is the fundamentally reason that CCDs have a low dynamic range but I won't go into that unless someone wants specifics. Pixim on the other hand can read pixels independently from each other. In effect they can read all pixels out at the same time but at different shutter speeds. This means you don't get the halo effect and if I remember right Pixim can read out pixels at 8 different shutter speeds at the same time. This gives it a much wider dynamic range than dual shot. I am not recommending any over the other, I'm just showing how they work. Even though I think Pixim have the better technology it doesn't necessarily follow that each camera using it will be the best solution. Each manufacturer has to make the most of the the technology. A poor DPS implementation will not be as good as a the best dual shot implementation.

The EQ600 uses the Pixim DPS system, there is a list of domes that use the same chipset on their website and I would think some of these will give similar performance to the EQ600. I can't post the link but if you try the obvious with pixim you will find them.

Hi Rory, That is really weird. If a camera is set up in a well lit scene the video level should not change when AGC is turned on. If it does then something is wrong with the camera or the way it is set up but as you see this with all cameras I am worried that I am pointing a finger at the way you set up cameras. A camera producing 1v pk-pk video a camera will not apply AGC. (unless you are using something like BLC that changes exposure and even then it is unlikely). If the video level increases when AGC is switched on (on a well lit scene) I would say the lens level is set too low. Sorry to question you on this.

Hi Guys, Rory - Yes you are right about the chips, in my defense I meant the same as you but wasn't clear in the way I said it. Two cameras with identical CCDs will perform pretty much the same with AGC off, two different types of Exview will perform differently. I haven't been involved with CCTV cameras for nearly 3 years now so I am out of touch but in my day there weren't different flavours of Exview. It was HyperHAD, SuperHAD and ExviewHAD. There was a new Exview just on the horizon when I left but I never tested it. Due to the time I've been away I'd say all my tests would be out of date (and I don't have any anyway!) Here's an interesting technical point for you in the form of a question. If you have two CCD's that are identical except for the resolution (standard resolution and high resolution), will there be any difference in sensitivity and if so why? I am pretty amazed to hear that you do not turn AGC on in the field. I worked for a camera manufacturer and it is possible that I suffered from iving in an ivory tower syndrome but I would have bet money on most installers turning AGC on. I am slightly puzzled by this line in your post. Also, I never leave a camera with AGC enabled, as it is fine for nighttime, but daytime is useless, at least down here. Personally when I test a camera I always test it with AGC disabled, as thats how it will be in the field. Are you saying that AGC effects your camera in daytime? It shouldn't, can you confirm. Ta.

I used to test CCTV cameras and publish lux levels for specifications so have some knowledge of these things. Firstly I'll agree with anyone who says don't trust published lux levels from manufacturer unless you know that both test in the same manner it isn't fair to compare lux levels. It is fair to use figures from independent tester such as magazine reviews but then you should only use these figures to show relative performances. You can't use them to say what image you will get in the real world at 1 lux. Here are the factors you need to know for a sensitivity test to be valid. The brightness of the light source, obviously The colour temperature or type of light used. If my camera was sensitive to IR would it be fair to quote a lux level if my light source included IR? Dimmed tungsten is warm and has more IR than filtered fluorescent. The reflectivity of the test scene. If you are viewing something that reflects better you will see more. The fstop of the lens. The signal level coming out of the rear of the camera. My specifications listed the lux level that was needed to give a certain signal out when viewing a scene of 80% reflectance in a quoted fstop lens. Even I didn't quote the colour temperature of my light. Here are the ways that manufacturers vary (cheat?) figures. Drop the signal level, say 30 IRE instead of 40 IRE. You need less light to achieve this so you lux level is lower. Use a faster lens. So beware! On the question of should AGC be on or off? I say on for this reason. If a camera is tested with AGC off you are in effect testing the sensitivity on the CCD only. There is very little any camera manufacture can do to alter this apart from cool the CCD which no one is going to do. So a cheap camera with the same Sony CCD will perform as well as the most expensive with the same chip. AGC is where the good cameras stand out. A good camera will have better signal to noise than a cheap on. When the light level drops and the signal is low you need good snr to keep the image useable. Unfortunately testing images with agc on is subjective. I could make a camera with very high gain and view a scene at low light and achieve a signal of 40 IRE but I might not actually have a useable picture. Ultimately the true test is to put cameras side by side. On the point that BLC makes the image brighter. It may well do so but this is nothing to do with sensitivity. BLC changes the way a camera sets its exposure algorithm. A certain image may become brighter as the camera has changed it's exposure but another scene could cause the image to darken. Neither will change sensitivity. Hope this makes sense CG.