Low light 4Ks

bug99

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Are there any reviews of the newer Stavis 8mp (4K) Dahua cameras? They would likely have less than 1/4 of the low light performance of the starlights and maybe 1/16 of the U starlight, but i think they will be way better than older 3mp and 4mp non- starvis models, and of coarse there is 2x the pixel density, and thus 2x the range for a given view angle (assuming it is above the noise floor of light).

@ljw2k recent post looks intriguing, and would love to know the trade offs (cost/range/noise).

What do the costs look like for the IPC-HFW5830E-Z5, the IPC-HDW5830R-Z, and the IPC-HFW4830E-S
 

nayr

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I'd suggest checking out the 6MP IMX178, it looks to be quite decent at low light..

the bitch about these UHD Starvis cameras is dont seem any of em have WDR, just the nearly worthless DWDR
 

bug99

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i saw that DWDR on one or more of them. what is that? digital wide dynamic range or something like that? if they are truly able to present 120dB of light intensity variation in the same frame, that should be way more than what would be needed for a human eye (limited to about 100 dB).
 

nayr

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Real WDR takes multiple exposures and merges the results for a more balanced image; Digital WDR is just photoshopping/postproccessing a single exposure to try to flatten out the image.. it dont work nearly as well as real WDR
 

hmjgriffon

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i saw that DWDR on one or more of them. what is that? digital wide dynamic range or something like that? if they are truly able to present 120dB of light intensity variation in the same frame, that should be way more than what would be needed for a human eye (limited to about 100 dB).
then why are there ultra starlights with 140db of wdr? - I'm genuinely curious because they have the ultra's with the bigger sensor and 120db wdr, and then the ultras with the same size sensor as the starlight but 140wdr, I'm curious which one is "better".
 

nayr

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its got a chipset capable of processing even more exposures; lets just say (bs numbers here) 120dB WDR is using 3 exposures at 3 different shutter speeds and merging the results.. 140dB WDR could be capable of processing 4-5 exposures in realtime.. resulting in even higher performance and better looking images.

I dont have any experience w/UltraWDR (140dB) but typically that level of performance is most desirable in moving platforms, dashcams for example need really good WDR because they can go from looking into the sun to a dark tunnel in a split second and it allows it to adapt quicker.. Another example is FPV RC Flyers who fly a remote controlled plane/multirotor from an onboard camera, those guys dont care about image quality at all and car all about having relaly good and really fast WDR so they can maintain orientation in their head as they are doing loops and the sun is continuously changing position... if you turn towards the sun and the image goes white for a few seconds while it adapts then the next image they likely to get is one of the ground approaching fast.. being able to see the horizon is key to those cameras.

For security use I'm struggling to see where UltraWDR is going to really be nessicary.. most of us run the 120dB WDR at like 20%, the best thing those Ultra cameras have going for them is SSA which is an even more advanced processing of the WDR capabilities of the sensor.. I'm betting SSA does an even better job on UlraWDR cams with even more capabilities on the chip.
 

hmjgriffon

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its got a chipset capable of processing even more exposures; lets just say (bs numbers here) 120dB WDR is using 3 exposures at 3 different shutter speeds and merging the results.. 140dB WDR could be capable of processing 4-5 exposures in realtime.. resulting in even higher performance and better looking images.

I dont have any experience w/UltraWDR (140dB) but typically that level of performance is most desirable in moving platforms, dashcams for example need really good WDR because they can go from looking into the sun to a dark tunnel in a split second and it allows it to adapt quicker.. Another example is FPV RC Flyers who fly a remote controlled plane/multirotor from an onboard camera, those guys dont care about image quality at all and car all about having relaly good and really fast WDR so they can maintain orientation in their head as they are doing loops and the sun is continuously changing position... if you turn towards the sun and the image goes white for a few seconds while it adapts then the next image they likely to get is one of the ground approaching fast.. being able to see the horizon is key to those cameras.

For security use I'm struggling to see where UltraWDR is going to really be nessicary.. most of us run the 120dB WDR at like 20%, the best thing those Ultra cameras have going for them is SSA which is an even more advanced processing of the WDR capabilities of the sensor.. I'm betting SSA does an even better job on UlraWDR cams with even more capabilities on the chip.

I absolutely get it now, welp, I'm supposed to (knock on wood) have an ultra WDR in my hands by next Wednesday so once I get it, I will test that out. I do agree though, the SSA feature is really really nice, ANY feature that lets the camera control something automatically is really nice because the conditions in front of your camera change all the time and so trying to not only set it yourself but only having that setting be good for certain situations sucks, you need the camera to be able to adapt on the fly. Lookin at my driveway cam today, the sun keeps going behind clouds and it goes from super fucking bright on half the frame to totally evened out dim lighting lol. This is another reason you need to just have lots of cameras so if one doesn't catch a good shot another one does because you'll go absolutely fucking bonkers trying to find the best manual settings. for a security use, for taking one time shots and short videos that you just want to look good? sure.
 

bug99

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i dont fully understand how they get to the big dBs here. What nayr says seems quite reasonable. one thing i might be able to add some color to is the more the bits in the DSP A/D, the slower it will be, by a lot. money helps, but time to settle the bits beyond the noise floor is a real world issue, so there is a trade off between good enough and fast enough.
 
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