interesting...that 3841T_ZAS doesn't make any mention of it being a starlight.....right I forgot the 5442 is technically the upgraded version of 5231....so would this cam be MORE of an upgrade if it's a starlight, meaning good low-light performance and 8mp?
Why the retreat from 1/1.8" sensors in the latest Dahua bullet cameras?
- Thread starter wtimothyholman
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interesting...that 3841T_ZAS doesn't make any mention of it being a starlight.....right I forgot the 5442 is technically the upgraded version of 5231....so would this cam be MORE of an upgrade if it's a starlight, meaning good low-light performance and 8mp?
chaosengine
Getting the hang of it
whoops...thanks for the correction...I had it stuck in my head this was 1/1.8".....so there's nothing like that yet right? as a turret. 8MP? you think the 5831R is the best 8mp turret varifocal still if being1/2.8" and 8MP will never be "Starlight", it's more for daylight.
put into a bright environment?
chaosengine
Getting the hang of it
Great quality either way. Wish mine looked as good at night.
bigredfish
Known around here
“Starlight” is nothing more than a marketing term, there is no universally accepted spec. I wouldn’t get too wrapped around the axle over it.
Dahua typically labels cameras “Starlight” with min illumination specs of .009 lux or better (lower number) @ a given F stop. (Typically F1.6 or better)
The 5231 series was labeled Starlight with a 1/2.8 sensor. At the time it was arguably the best low light camera in its price range. Now the 5000 and 7000 series with the 1/1.8 put it to shame.
Dahua typically labels cameras “Starlight” with min illumination specs of .009 lux or better (lower number) @ a given F stop. (Typically F1.6 or better)
The 5231 series was labeled Starlight with a 1/2.8 sensor. At the time it was arguably the best low light camera in its price range. Now the 5000 and 7000 series with the 1/1.8 put it to shame.
I did some research for another thread and found that 1/1.8, 1/2.8, etc is not the size of the sensor. It's the "class" or "type" of the sensor. Some forum posts say that the Dahua 2MP starlights use the 1/2.8 IMX290 or IMX291 sensor. The spec sheet says its diagonal size is 0.2543", or 1/3.93". Not very close to 1/2.8"
The 1/2.8" number is confusing and comes from the history of television camera tubes. It doesn't imply the active sensing area is 0.357". Look up "the rule of 16". It is still useful however as it does give a size that can be compared - the larger the number the bigger the sensor. What we really care about is the active sensing area (output image size) which is a ratio of the 1/2.8".
How did you find which sensor is in which Dahua camera?
How did you find which sensor is in which Dahua camera?
"Starlight" may be Dahua's marketing term, but "STARVIS" is Sony's trademarked name of a line of their sensors. Dahua does identify STARVIS as the sensor inside the 5231. There are a few variants of the Sony STARVIS 1/2.8" sensors so I'm curious how people are able to figure out which is for which camera. It also appears that the IMX290/IMX291 aren't current production and have been replaced with new chips. Looking at Sony's lineup, there aren't any current 1/1.8" 2MP sensors anymore. They do have them in 4MP and 8MP though.
Sony does have a 1/1.2" in 2MP (IMX482). I'd definitely be interested in seeing that.
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I find this out only indirectly from other forum posts, like this one: Dahua 5231R-Z vs SD59225U-HNI WDR
So technically, coming from me it's hearsay evidence.
All I found for this was related to finance or camera shutter speeds, but I did hit paydirt chasing camera tube history. And the answer is:
The actual diagonal sensor size is approximately 2/3 of its "class" or "type", which is commonly and incorrectly listed as the sensor size in camera specs.
A good explanation is here: Optical format - Wikipedia
"Optical format is a hypothetical measurement approximately 50% larger than the true diagonal size of a solid-state photo sensor.
.......The optical format is approximately the diagonal length of the sensor multiplied by 3/2. The result is expressed in inches and is usually (but not always) rounded to a convenient fraction. "
Thanks for the hints. The old dog learned yet another new trick.
bigredfish
Known around here
Correct. And as you note there are a variety of STARVIS sensors. It is effectively also a marketing term not an actual universal spec.
CCTVCam
Known around here
- Sep 25, 2017
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So far, 8mp cameras don't have the l;ow light performance of the 4mp ones. By increasing the pixels from 4mp to 8mp on a 1/1.8" sensor, you're halving the size of each pixels ie double the number on the same size die. As a lot (not all) of the low light perfoprmance is down to the phsical size of the pixel, doubling the pixel density and halving the pixel size will have a significant impact on low light performance. I'm unsure which cameras have been tested on here, but there are members who get to test almost every new camera that's popular eg Looney and others, and generally the finding atm is 4mp 1/1.8" is the sweet spot for light sensitivity vs pixel density. The one real exception to this is a Sony CCTV camera, but it costs £5,000 for the bare camera and approx £10,000 when a lens, enclosure and the other bits needed to make it work are added. Someone on here has one, although I'm unsure where the thread is buried. Needless to say, wealth is needed if you intend to install one, never mind a whole household system of these!
Either way you calculate it, 2/3rds times a larger number = a larger outcome making the diagonal size a good measure of the actual sensor size.
I believe the downsize is probably a money saving move. The smaller the lens the cheaper usually and so moving smaller saves Dahua money = more profit for the same srp of camera. An led is a cheap at only a few cents compared to the cost of a larger lens at maybe a few dollars to tens of dollars more. So it makes sense to stick a smaller cheaper sensor in and spend a few cents on an LED, rather than spending on the more expensive sensor and then the more expensive lens ata cost of several tens of dollars. Unfortunately, it's not the best move for their customers in my opinion. The way forward as I see it is probably going to be 1 inch sensors when they become sensitive and cheap enough for them to make sense.
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I really like the white light from the porch lamp. I've turned off all camera LED/IR and have gone with warm LED lights in all outside lighting fixtures. I just seem to get a lot better quality video this way. Faces are clear and easy to recognize. Camera IR's seem to wash everything out and are pretty much useless on my cameras.
Thanks again!