neteyes 0 Posted October 18, 2004 We are having a problem with the image quality of some of our cameras, I wanted to know if anyone felt that the height of the cameras can affect the quality of the image the camera will produce. For example will a box camera in a housing set at 12 feet on a building versus the same camer set at 18 to 20 feet on the building produce a different quality image or will it only produce a different angle. Share this post Link to post Share on other sites
cctv_down_under 0 Posted October 19, 2004 mostly a different angle, we ll not really different, just more of an angle, because further away, but that also depends on how you set your lens. Some things to note are though, that if you are looking fom further away, you have to consider the light that will reach the camera for example street lights are not at that hieght, plus you have more chance of glare etc, basically the camera will probably work harder, mind you the lighting will be more constant because you may not have to deal with shadows etc, what you might find is that you put the camera up there and chose the wrong lens for the job, so your focal point has fallen short of the objects you want to see, try focussing in on the objects you want while doing the camera, the field of view will change with the distance so choose your lens wisely. Chances are that your focal point is too close to the camera and you may not have adjusted the backfocus when setting the camera up, try setting it at night time. One other thing to note, if the camera moves because of wind etc, each movement can make the camera adjust the signal to balance the output, this can result in poor picture quality fromt he camera hunting all the time. Regards, GC Share this post Link to post Share on other sites
Thomas 0 Posted October 19, 2004 It techincally is a bit further away. If we assume a point 10 ft away is our focal point then..... 12 ft= 12 2 + 10 2 = C 2 144 + 100 = C 2 244 = C 2 C = 15.62 ft... 18 ft = 18 2 + 10 2 = C 2 324 + 100 = C 2 424 = C 2 20.591 ft. The higher you make the camera, or the further the focal point the greater this forumla grows. And who says you never use algebra in the real world.[/code] Share this post Link to post Share on other sites
Cooperman 0 Posted October 19, 2004 neteyes, I think DVR Expert Australia is probably right that the focus hasn't been set up correctly on your camera; ditto all the advice on lighting and glare. The quality of a picture will be dictated by the camera, and to a significant degree by the lens, but as you increase the height of a camera, it generally reduces its effectiveness for recognition purposes. The overall picture quality though, shouldn't be affected. There are very few applications that actually benefit by increasing the mounting height of a camera; anything much over 12 feet is usually inappropriate. I think I'll have to ask Thomas nicely for some algebra lessons ... maths was never really my strong point! Share this post Link to post Share on other sites
cctv_down_under 0 Posted October 20, 2004 Also keep in mind if camera is in a housing, if you put the lens a bit back from the glass of the enclosure, then that may be fine for close shots, but it can create a second lens from different viewing distances, try to get it as close to the glass front as possible as long as you have a glare shroud that is? Share this post Link to post Share on other sites
rikky 0 Posted October 20, 2004 DVR_EXpert, How can you define the best combination of focal point (distance to the object) and the lens? Lens specs do only indicate the minimum focal distance? So beyond that, every lens should fit? Share this post Link to post Share on other sites
