PTZ 10x 2MP vs. 20x 1MP

[braddie]

All else being equal, if you had to choose between a PTZ camera with a higher optical zoom or another one with a higher resolution, which would you pick? For example, 10x 2MP or 20x 1MP? And in what scenarios would you pick one over the other? The main things I can think of are: night vision, face/license plate recognizability.

 

[alphawave7]

10X/2MP all day long, for what you describe. Only those looking for far distances would benefit from 20X (and we even covet a 30X in our future).

 

[wxman]

Tough question to answer because there are so many different scenarios where one may be better than the other. It is also possible that a 10X could have MORE effective zoom than a 20X, depending on the mm value of the lens. The higher the mm number, the closer zoomed in the picture will be....A wide-view lens (say 2.8mm) with 20X zoom will be 56mm zoomed in all the way to 20X; whereas a 10X lens that starts more zoomed in (say a starting point of 6mm) will be at 60mm when zoomed in all the way at 10X...Always important to check the mm range to see just how much zoom you're getting and to confirm that you'll be able to see everything you want to see when fully zoomed out.

If you have a wide area that you want to be able to cover at the same time, then you would probably want the one with the lowest mm starting point. If a wide angle of view is not important and most of what you want to see is far away, the one that ends in the highest mm zoomed in would be the best. If everything that you need to see would fall within the ranges of either lens, then the higher megapixel sensor would likely be the best....But even that can be subjective to the image processing chip as some here have stated that the Huisun 2mp cams with newer model processing chips gives a clearer/sharper image than Hikvision 4mp cams. Also lower megapixel sensors tend to perform better in low light. If low light night video is what you're aiming at, a 1mp cam that can produce a clean image with little noise would be better than a 12mp cam with extreme noise.

It really is a case to where the best answer would depend on all specs being completely equal and your specific situation.

 

[braddie]

Tough question to answer because there are so many different scenarios where one may be better than the other. It is also possible that a 10X could have MORE effective zoom than a 20X, depending on the mm value of the lens. The higher the mm number, the closer zoomed in the picture will be....A wide-view lens (say 2.8mm) with 20X zoom will be 56mm zoomed in all the way to 20X; whereas a 10X lens that starts more zoomed in (say a starting point of 6mm) will be at 60mm when zoomed in all the way at 10X...Always important to check the mm range to see just how much zoom you're getting and to confirm that you'll be able to see everything you want to see when fully zoomed out.

If you have a wide area that you want to be able to cover at the same time, then you would probably want the one with the lowest mm starting point. If a wide angle of view is not important and most of what you want to see is far away, the one that ends in the highest mm zoomed in would be the best. If everything that you need to see would fall within the ranges of either lens, then the higher megapixel sensor would likely be the best....But even that can be subjective to the image processing chip as some here have stated that the Huisun 2mp cams with newer model processing chips gives a clearer/sharper image than Hikvision 4mp cams. Also lower megapixel sensors tend to perform better in low light. If low light night video is what you're aiming at, a 1mp cam that can produce a clean image with little noise would be better than a 12mp cam with extreme noise.

It really is a case to where the best answer would depend on all specs being completely equal and your specific situation.

I'm not an expert in photography/camera theory, but I assume a shorter exposure time would be better suited for capturing moving objects in low light conditions. Would one camera have an advantage over the other in needing less exposure (assuming same sensor size and quality)?

 

[Kawboy12R]

A shorter (faster) exposure is better for capturing moving objects with less blur regardless of light level, but if you add low light into that equation then you're fighting video noise at the expense of lower blur. Low blur with huge grains is just as bad on a moving target as high blur for a moving target when the background is nice and crisp. With the exposure speed set to an acceptable level of graininess, you just have to hope that your target slows down enough to reduce the blurring that the longer exposure gives you. A long exposure would work fine if they'd just stop in place once for a good crisp face shot with no grain. Good luck on that one, especially if they're just walking or running through the scene. Shortening the exposure broadens that opportunity for them to slow down enough for an acceptable level of blur but might just make the best possible mugshot miserable because you've lost the picture quality completely from too fast an exposure or, looking at it the other way, expecting too much from your camera without providing it enough light to do its job. Even a cheap camera works fine with proper planning (control the angle, know the distance, use the right lens, and provide enough light). Better cameras just allow the installer to broaden the effectiveness of a single camera.

Everything else being equal (it rarely is), it's easier to light up 1 million pixels on a sensor of a given size than 2 million on the same sized sensor, so theoretically you'd get less noise and be able to speed up the exposure (thus cutting down the number of photons per unit of time) for less blur with a 1MP sensor than a 2MP because twice as many photons are hitting each pixel and trying to light it up. You could always have a lousy insensitive 1/3" 1MP sensor pitted against a fantastic 1/3" 2MP sensor and have the 2MP one win easily. Lux ratings are the best way for a consumer to judge this in combination with other things like the installed lens but as far as I've ever heard there are no standardized tests between companies even if they decided not to lie or fudge things a bit.