Getting cameras with the right MP to sensor size ratio

[lecce]

First post here, please be gentle!

I've been attempting to do my research on Hikvision cameras. I have read the advice here and elsewhere about ColorVu being a gimmick, exposure times being critical to getting useful motion shots at night, sensor size vs MP being a key ratio etc...

Sensor to resolution for good performance at night -
720P - 1/3" = .333"
2MP - 1/2.8" = .357" (think a .38 caliber bullet)
4MP - 1/1.8" = .555" (bigger than a .50 caliber bullet or ball)
8MP - 1/1.2" = .833" (bigger than a 20mm chain gun round)

do not buy a 4MP camera that is anything smaller than a 1/1.8" sensor. Do not buy a 2MP camera that is anything smaller than a 1/2.8" sensor. Do not buy a 4K (8MP) camera on anything smaller than a 1/1.2" sensor. Unfortunately, most 4k (8MP) cams are on the same sensor as a 2MP and thus the 2MP will kick its butt all night long as the 4k will need 4 times the light than the 2MP... 4k will do very poor at night unless you have stadium quality lighting (well a lot of lighting LOL). Starlight, ColorVu, Full Color, etc. are simply marketing terms with no increased technological advances.

What I am now struggling with is finding a Hikvision camera that meets my needs, at least in the DS-2CDxxxx range.

The only models that seem to have a 1/1.8" for 4MP or a 1/1.2" for 8MP are the xx47G2 / xx87G2. However, as far as I can see, the xxx7G2 models are all ColorVu with no ability to see IR. That's no good for me - in my neighbourhood washing my property in white light is not workable - think small, tightly clusters houses where my lights would end up in someone's bedroom window half the time. I did try filtering on the Hikvision site's product pages but couldn't seem to find any other options.

Furthermore, I was considering some varifocals, in particular as a good way to test out the required focal lengths - but even the G2 varifocals seem to have 1/3" sensors.

I'm guessing that this is just because these are just one-up from the entry-level cameras? Is my only option to step up a range? Or is this advice really the "gold standard" and actually the 7G2's are probably going to be reasonable. I'm pretty much on the verge of just buying some used off eBay and trying them out...or moving over to Dahua who I hear are also good.

Another nervousness with the 7G2's - minimum focus distance. With the F1.0 aperture it seems 3meters plus is the minimum. I have some very tight areas I was hoping to cover with 2.8mm's (porch etc) but I don't see that working with blurry shots. As far as I understand it that's just physics - close focus at wide open apertures on a DSLR doesn't work either...

 

[wittaj]

Welcome!

Sensor size is a big deal.

Now you won't know what you don't know and won't know what you are missing until you have experienced a higher resolution camera on a sensor designed for a lower resolution.

Most people buy surveillance cameras to capture clean images of perps at night and they are not going to stop and pose for a picture...If it can capture in the night, then it will capture in the day....

Any camera can have settings set to provide a nice bright static image at night by slowing the shutter down and cranking up the gain, but then motion is useless.

Almost any camera can do well in the daytime with enough light, even cameras that are 8MP put on a sensor designed for 2MP. But keep in mind that usually the processor and other stuff are still designed around 2MP, so the camera struggles trying to keep up with 8MP worth of data.

In most instances, you want to get a camera that will perform at your location for the worse situation - which for most of us is at night when it is dark and there is little to no light.

If a camera performs at night, it is easier to tweak settings to make it work during the day than it is the other way around. The cameras will certainly perform better in the day.

Once you get a camera on the proper MP/sensor ratio, you will see how underperforming a 4MP on a 1/3" sensor is...

Here is a real world example. Even with a floodlight, there simply wasn't enough light to make the cheaper 4MP on the 1/2.7" sensor (which is larger than the 1/3" sensor so it would be even worse) go into color:




And a 4MP on the 1/1.8" sensor camera (different deer LOL) that the camera was able to go to color based on the larger sensor:



Which do you think is the better image?

And you are correct on near focus - people think these cameras are infinity focus and they are not. Some do better than others, and some cameras have a very specific target focus range and anything outside of those distances are going to be blurry.

Another thing we can say is these are not DSLR cameras, so if you have experience with those, you might have to forget what you know about DSLR and high end photography cameras LOL as you play with these. Almost everyone that has come here with experience in DSLR cameras struggle with these cameras. Every one of these cameras have more processing of the images than a DSLR camera. Some are worse than others. Then there is the compression of the video, etc. Turn off NR on one of these cameras and you will see how much processing is used.

You will find a BIG difference between photography equipment and these cameras. Things like trying to match focal lengths are tough because it may be crystal clear on high end DSLR and not be clear with these types of cameras. Digital zoom works better on DSLR cameras than these. The sensors and optics just are not at the same level. These cameras are designed for 24/7 use with abuse from the elements. DSLR cameras are designed for a different working environment and purpose. Hang a DSLR camera outside and see how long it lasts LOL! But the quality would be better for the time it was working (but also a lot more storage needed too).

Remember these are surveillance cameras, not DSLR cameras, so you have to check your expectations. For example, you can see individual hairs and skin pores with DSLR photography equipment and you won't with these kinds of cameras. These are for a different use and different expectations.

• Sensor Size - a full frame DSLR sensor size is 864mm^2; whereas a 1/2.8" sensor popular on many cameras would be 20mm^2, so the "real" camera can collect over 40 times more light than a surveillance camera. And this doesn't even account for less light available for an 8MP versus 2MP for the same size sensor.
• Shutter Speed (Exposure) - Taking a picture with a "real" camera, you can slow the shutter down to 1/2s or longer for a nice clean picture of a person not moving. Perps rarely stand still and we need a shutter of at least 1/60s to minimize the blur.
• Aperture - With a "real" camera you focus on a specific part of the field of view, while a surveillance needs to focus on things in the foreground and background, which means the aperture is smaller, further compounding the light issue.
• Compression - A single 8MP image from a "real" camera could be upwards of 5MB of storage. In surveillance cameras, if you record at 15FPS, every second of video could be 75MB or more, which could equate to 6.5TB per day per camera. Obviously most are not going to have that kind of storage, so lossy compression algorithms are used to reduce storage and network bandwidth requirement, and that can add noise.
• Environment - a "real" camera is used mainly under ideal conditions, whereas a surveillance camera is going 24/7 in every type of element, so the design and size impacts its capabilities.

Many here go with Dahua, so unless you are hung up or have a need for Hikvision, you will find more variety in the Dahua line.

Since you mentioned ColorVu, I wanted to point out that many people have come here after buying the Hikvision ColorVu series (or any full color type camera) expressing their disappointment in the picture quality of the camera because they were expecting magic. If you do not have ambient light outside or do not like the white LED lights on, you are better off with cameras that can see infrared. ColorVu type cameras cannot see infrared, so you can't add infrared later.

Here is link to a thread of many that shows the disappointment of many thinking a ColorVu camera was magic and could defy physics. Full Color type cameras are great if you have light, but will be horrible if you do not have enough light.

Initial review of the DS-2CD2347G2-L(U) ColorVu 2.0 IP camera.

There seems to be more posts started here with complaints about the Hik version at night than the 4K/X. If you want a full color, the 4K/X is a better choice.

Or maybe the people that buy the Hikvision version are naive and think they are magic and the ones that buy the 4K/X are educated as to the proper placement for this type of camera LOL...

https://www.amazon.com/EmpireTech-Full-Color-Syarlight-Turret-IPC-Color4K-T/dp/B0BC18KVF7/ref=sr_1_3?imprToken=eNnu.Pmf5hsW5hcTVECAQg&linkCode=w61&m=A329YQ83EBQGJF&marketplaceID=ATVPDKIKX0DER&qid=1672832699&redirect=true&s=merchant-items&slotNum=0&sr=1-3

https://www.amazon.com/EmpireTech-Full-Color-Weatherproof-Detection-IPC-Color4K-X/dp/B099R9WG9M/ref=sr_1_18?imprToken=eNnu.Pmf5hsW5hcTVECAQg&linkCode=w61&m=A329YQ83EBQGJF&marketplaceID=ATVPDKIKX0DER&qid=1672832719&redirect=true&s=merchant-items&slotNum=0&sr=1-18&th=1

But with any full color type camera, if you do not have enough ambient light or do not want to use the built-in white LED, then getting a camera with infrared capabilities is the best bet.

 

[lecce]

Thank you for the detailed response, this is a really good summation across multiple different points of the days of research I've been doing! Could have saved myself the time though I'm fairly comfortable with all the facts presented. What I'm really trying to get down to is the specific point around sensor size to MP ratio, and whether there are Hikvision cameras that meet it. As I've said I'm specifically not interested in their ColorVu cameras.

Many here go with Dahua, so unless you are hung up or have a need for Hikvision, you will find more variety in the Hikvision line.

Not quite sure I follow the last part of this sentence sorry?

 

[mat200]

..

The only models that seem to have a 1/1.8" for 4MP or a 1/1.2" for 8MP are the xx47G2 / xx87G2. However, as far as I can see, the xxx7G2 models are all ColorVu with no ability to see IR. That's no good for me - in my neighbourhood washing my property in white light is not workable

...or moving over to Dahua who I hear are also good.

Welcome @lecce

Many of us have gone Dahua OEM as Andy provided access to numerous models easily .. so you may want to consider that route if you can not source Hikvision cameras readily.

 

[Spirch]

adding to what wittaj said (feel free to use that as future example)

this is an example of colorvu 4k

this is exposure time of 1/120

no light other than street light


led


extra light

 

[wittaj]

Thank you for the detailed response, this is a really good summation across multiple different points of the days of research I've been doing! Could have saved myself the time though I'm fairly comfortable with all the facts presented. What I'm really trying to get down to is the specific point around sensor size to MP ratio, and whether there are Hikvision cameras that meet it. As I've said I'm specifically not interested in their ColorVu cameras.




Not quite sure I follow the last part of this sentence sorry?

What I meant was some people are already invested into a particular brand by having an NVR already. Best practice is to match NVR brand with camera brand to ensure full functionality.

I realize now I said Hikvision instead of Dahua in regards to camera variety amount, but my point was you will find more options and cameras at different price points and matching ideal MP/sensor ratios in the Dahua line, so unless you have already invested in the Hikvision platform, take a look around what Dahua has to offer.

 

[fullboogie]

I don't think ColorVu buyers with unrealistic expectations make those cameras bad or disappointing. That's the buyer's fault. In the right application they are terrific.

 

[wittaj]

A "buyer with unrealistic expectations" is the buyers fault.

I said we see complaints from people that have purchased any type of full color camera because they fail to understand that all cameras need light, either visible or infrared.

It just so happens we see more complaints from the ColorVu series than we do those put out by Dahua and other brands, probably because they hit the market first.

It is simply using a great camera in the wrong place.

But yes, a full color camera used in the right application are terrific.

 

[sinusoidal]

This is an interesting discussion on sensor size and MP ratio. While I agree, I also read that dSLR's and mirrorles cameras with higher pixel density perform more or less the "same" despite the same sensor size but higher pixel density.

The concensus here is that on the pixel level the camera with the higher pixel density will have more noise but will have the same amount of noise when zoomed out to normal viewing.

Am I missing something? Maybe this only applies to POE and not dSLRs/Mirrorless cameras?

Here's a link discussing this:

DPReview TV: Why lower resolution sensors are not better in low light

A common belief in the camera world is that lower resolution cameras – and larger pixels – perform better in low light. In this video we illustrate why you should question that bit of conventional wisdom.

m.dpreview.com

 

[wittaj]

This is an interesting discussion on sensor size and MP ratio. While I agree, I also read that dSLR's and mirrorles cameras with higher pixel density perform more or less the "same" despite the same sensor size but higher pixel density.

The concensus here is that on the pixel level the camera with the higher pixel density will have more noise but will have the same amount of noise when zoomed out to normal viewing.

Am I missing something? Maybe this only applies to POE and not dSLRs/Mirrorless cameras?

Here's a link discussing this:

DPReview TV: Why lower resolution sensors are not better in low light

A common belief in the camera world is that lower resolution cameras – and larger pixels – perform better in low light. In this video we illustrate why you should question that bit of conventional wisdom.

m.dpreview.com

MP/sensor size as we are discussing it refers to surveillance cameras, not DSLR cameras.

Refer back to what I said above.

In addition to what I mentioned, many of those DSLR cameras utilize pixel shifting, which isn't used in surveillance cameras. That also allows them to at least double the resolution.

Another thing we can say is these are not DSLR cameras, so if you have experience with those, you might have to forget what you know about DSLR and high end photography cameras LOL as you play with these. Almost everyone that has come here with experience in DSLR cameras struggle with these cameras. Every one of these cameras have more processing of the images than a DSLR camera. Some are worse than others. Then there is the compression of the video, etc. Turn off NR on one of these cameras and you will see how much processing is used.

You will find a BIG difference between photography equipment and these cameras. Things like trying to match focal lengths are tough because it may be crystal clear on high end DSLR and not be clear with these types of cameras. Digital zoom works better on DSLR cameras than these. The sensors and optics just are not at the same level. These cameras are designed for 24/7 use with abuse from the elements. DSLR cameras are designed for a different working environment and purpose. Hang a DSLR camera outside and see how long it lasts LOL! But the quality would be better for the time it was working (but also a lot more storage needed too).

Remember these are surveillance cameras, not DSLR cameras, so you have to check your expectations. For example, you can see individual hairs and skin pores with DSLR photography equipment and you won't with these kinds of cameras. These are for a different use and different expectations.

• Sensor Size - a full frame DSLR sensor size is 864mm^2; whereas a 1/2.8" sensor popular on many cameras would be 20mm^2, so the "real" camera can collect over 40 times more light than a surveillance camera. And this doesn't even account for less light available for an 8MP versus 2MP for the same size sensor.
• Shutter Speed (Exposure) - Taking a picture with a "real" camera, you can slow the shutter down to 1/2s or longer for a nice clean picture of a person not moving. Perps rarely stand still and we need a shutter of at least 1/60s to minimize the blur.
• Aperture - With a "real" camera you focus on a specific part of the field of view, while a surveillance needs to focus on things in the foreground and background, which means the aperture is smaller, further compounding the light issue.
• Compression - A single 8MP image from a "real" camera could be upwards of 5MB of storage. In surveillance cameras, if you record at 15FPS, every second of video could be 75MB or more, which could equate to 6.5TB per day per camera. Obviously most are not going to have that kind of storage, so lossy compression algorithms are used to reduce storage and network bandwidth requirement, and that can add noise.
• Environment - a "real" camera is used mainly under ideal conditions, whereas a surveillance camera is going 24/7 in every type of element, so the design and size impacts its capabilities.

 

[sinusoidal]

Excellent points! I was doing an apple to oranges. The sensors in dSLRs are huge!

 

[kd4e]

Key Takeaways from this thread for me ...

wittaj "... do not buy a 4MP camera that is anything smaller than a 1/1.8" sensor. Do not buy a 2MP camera that is anything smaller than a 1/2.8" sensor. Do not buy a 4K (8MP) camera on anything smaller than a 1/1.2" sensor."

"... if you record at 15FPS, every second of video could be 75MB or more, which could equate to 6.5TB per day per camera. (... lossy compression algorithms are used to reduce storage and network bandwidth requirement, and that can add noise.)"

"In most instances, you want to get a camera that will perform at your location for the worse situation - which for most of us is at night when it is dark and there is little to no light."

"If a camera performs at night, it is easier to tweak settings to make it work during the day than it is the other way around."

Thanks for the education!

BTW: I take this to mean that a 6MP IP PoE Turret Camera Outdoor - 1/2.7” 0.002 Lux@F1.6 25fps Starlight is a bad idea ... but would be better if 2MP?

 

[wittaj]

That is correct - the 2MP would perform better than the 6MP since they are about the same sensor size.

 

[bob1202]

Hi everyone,

Thanks @wittaj for all the explanations. Just to clarify, I understand the point of sensor size for low light color images. Does it also applys to infrared ? My point is that I don't need color images at low light, black and white IR are fine for me. Do I still need a 1/1.8'' sensor for a 4 MP camera if I'm fine with black and white IR? Although It makes sense that a bigger sensor also allows more IR to come in, but since 4MP cameras with 1/1.8'' are rare I prefer to clarify.

Thanks in advance.

 

[wittaj]

Hi everyone,

Thanks @wittaj for all the explanations. Just to clarify, I understand the point of sensor size for low light color images. Does it also applys to infrared ? My point is that I don't need color images at low light, black and white IR are fine for me. Do I still need a 1/1.8'' sensor for a 4 MP camera if I'm fine with black and white IR? Although It makes sense that a bigger sensor also allows more IR to come in, but since 4MP cameras with 1/1.8'' are rare I prefer to clarify.

Thanks in advance.

Yes the same applies.

Once you speed up the shutter to minimize motion blur, you will find that the IR isn't very bright.

You could find that the shutter speed needs to be cut in half or more for a larger MP on the same size sensor as a lower MP.

That image above of the deer in B/W was aided with spotlights. With just IR you aren't seeing past 15 feet in that field of view.

Inside you can probably get away with it as the IR bounces off the walls, but outside with say a 1/120 shutter you will see a big difference if they are the same size sensor.

Almost the entire 4MP line of Dahua has IR.

 

[TonyR]

Hi everyone,

Thanks @wittaj for all the explanations. Just to clarify, I understand the point of sensor size for low light color images. Does it also applys to infrared ? My point is that I don't need color images at low light, black and white IR are fine for me. Do I still need a 1/1.8'' sensor for a 4 MP camera if I'm fine with black and white IR? Although It makes sense that a bigger sensor also allows more IR to come in, but since 4MP cameras with 1/1.8'' are rare I prefer to clarify.

Thanks in advance.

@wittaj , please correct me if I'm wrong but a larger sensor for a given MP cam will allow a faster shutter speed to be used when the low light conditions exist and the IR is on and therefore provide images with less blur if there's motion. A smaller sensor under the same lighting conditions would require a slower shutter speed thus likely producing blur if there is sufficient motion.

And perps / prowlers, etc. rarely stand still......

 

[TonyR]

Hi everyone,

Thanks @wittaj for all the explanations. Just to clarify, I understand the point of sensor size for low light color images. Does it also applys to infrared ? My point is that I don't need color images at low light, black and white IR are fine for me. Do I still need a 1/1.8'' sensor for a 4 MP camera if I'm fine with black and white IR? Although It makes sense that a bigger sensor also allows more IR to come in, but since 4MP cameras with 1/1.8'' are rare I prefer to clarify.

Thanks in advance.

Never mind.....wittaj types faster than me!

 

[bob1202]

Fast indeed =) Thanks for the answer ! I'll then stay with my first choice of a 5442EP-ZE-S3 for the 1/1,8'' lens !

 

[observant1]

I have two 8mp cams on 1/2.7 sensors. They look great in daylight. I have a bright driveway light. About 1 year ago 3 kids in hoodies were trying door handles on cars. they tryde mine (it was locked) but even with a fairly bright driveway light they were very blury and impossible to identify. The video was almost worthless. I have added more lighting and went with a 4mp on a 1/1.8 sensor. It shows in color all the time if my lights are on.

Huge differenc at night.

 

[lane777smith]

You can always get the Hybrid variant of the Hikvision 2347 that has both IR and Full color options Hikvision 8MP 4MP 4K ColorVu IP Camera Smart DS-2CD2387G2H-LISU/SL Audio Alarm | eBay