When/Where to use 8MP-1/1.2 vs. 4MP-1/1.8?
- Thread starter josephny
- Start date
The sensor does not change. The size of the pixel stays the same and lets in the same amount of light regardless of the resolution feed you choose.
Understood that the sensor size doesn't change.
I can't say I understand what exactly does happen when one configures a camera at a lower-than-maximum resolution.
sebastiantombs
Known around here
Assuming the same sensor size for an 8MP and a 4MP camera, the 8MP camera has twice as many pixels in the same size area that the 4MP camera has. That also means that each pixel in the 8MP only gets half the light that a pixel gets in a 4MP camera. These numbers are generalized and are also effected by the quality of the electronic processing differences between the two cameras.
The short answer is that electronically resizing the image, down sizing from 8MP to 4MP, cannot increase the amount of light that each pixel receives. Downsizing the resolution may be necessary if you're using an NVR and the 8MP resolution exceeds its bandwidth capabilities.
The short answer is that electronically resizing the image, down sizing from 8MP to 4MP, cannot increase the amount of light that each pixel receives. Downsizing the resolution may be necessary if you're using an NVR and the 8MP resolution exceeds its bandwidth capabilities.
Downrezing a camera does not work - It is still using the 8 million pixels - the camera doesn't change the "pixel resolution screen" on the camera when you go from 8MP to 4MP. The sensor still needs 2 times the light going from 8MP to 4MP, so the native 4MP camera will result in a better image at night. The firmware will make some algorithm attempt at downrezing it, but it could be a complete crap image or a somewhat usable image, but if there is a concern that the 8MP isn't performing or wouldn't perform well at night, then it is better to go with the 4MP.
I have a 4MP and 2MP on the same 1/2.8" sensor and the picture quality is quite different between the two and the 2MP kicks it's butt at night.
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.
My 2MP cameras outperform my neighbors 4K (8MP) cameras....why....because they are both on the same size sensor.
When we had a thief come thru here and get into a lot of cars, the police couldn't use one video or photo from anyone's system but mine. Not even my other neighbors $1,300 8MP system provided useful info - the cams just didn't cut it at night.
My neighbor tried the "I will just downrez the 8MP to 2MP" and the image was a soft dark mess.
His system wasn't even a year old and after that event has started replacing with cameras purchased from @EMPIRETECANDY here based on my recommendation and seeing my results. He is still shocked a 2MP camera performs better than his 4k cameras and he cannot figure out why downrezing from 8MP to 2MP doesn't work properly... It is all about the amount of light needed and getting the right camera for the right location and downrezing doesn't change the physics of the camera
I have a 4MP and 2MP on the same 1/2.8" sensor and the picture quality is quite different between the two and the 2MP kicks it's butt at night.
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.
My 2MP cameras outperform my neighbors 4K (8MP) cameras....why....because they are both on the same size sensor.
When we had a thief come thru here and get into a lot of cars, the police couldn't use one video or photo from anyone's system but mine. Not even my other neighbors $1,300 8MP system provided useful info - the cams just didn't cut it at night.
My neighbor tried the "I will just downrez the 8MP to 2MP" and the image was a soft dark mess.
His system wasn't even a year old and after that event has started replacing with cameras purchased from @EMPIRETECANDY here based on my recommendation and seeing my results. He is still shocked a 2MP camera performs better than his 4k cameras and he cannot figure out why downrezing from 8MP to 2MP doesn't work properly... It is all about the amount of light needed and getting the right camera for the right location and downrezing doesn't change the physics of the camera
that’s extremely helpful. Thank you.
I’m sure I’m being extra slow, but could you describe a situation or environment where a 4K/1.2 camera would perform better?
mat200
IPCT Contributor
- Jan 17, 2017
- 16,123
- 27,084
Good question .. @josephny
"I'm wondering if there are general guidelines for when 8MP-1/1.2 cameras would be smarter to use vs. 4MP-1/1.8 cameras "
Check the reviews by members on the 8MP 1/1.2" sensors models .. often members will do a comparison and contrast with a 4MP 1/1.8" model.
In general a 8MP with the same pixel size / FOV / f-stop and compute power per pixel .. ( I'm assuming similarly effective pixel / image capture ) compared to a like model 4MP will give you
A 8MP 2x the DORI distance compared to a 2MP
A 4MP gives you 1.5x the DORI distance compared to a 2MP
So a 8MP will give you a 2/1.5 = 1.33x the DORI distance compared to the 4MP .. again assuming the same effective pixel image capture ..
Also expect to need more storage space ( probably not as big of a concern unless you have tons of camera feeds you need to keep for a longer period of time .. )
For most of us, it is also a question of budget ..
Personally, if budget was not a concern .. I'd switch out more of my cameras with 8PM 1/1.2" models .. as it now my budget is stopping me .. ( lol, darn food prices eating away my side cash .. )
Great info!
So (all else being equal) an 8MP/1.2 can be described as 'somewhat better' or '33% farther DORI distance' than a 4MP/1.8 camera.
I'll stop bugging you guys -- I think i understand enough now to feel comfortable concluding that (even) a 4MP/1.8 would be a huge improvement over my crappy Reolink (4MP/2.49 and 5MP/2.7") and SV3C (5MP/2.8") cams.
Thank you all so very much.
I ordered 1 of each of the following for initial testing from @EMPIRETECANDY:
IPC-B5442E-Z4E
IPC-Color4K-X in 6mm
Excited!
The 4K 1/1.2" sensor will perform better over a comparable 4MP field of view if there is enough ambient light or you do not care about using the white LED of the camera.
If it is pitch black and you do not want the white LED light on from the camera, then you are better off with the 4MP 5442 that can see infrared. The 4K camera cannot see infrared.
The DORI numbers are estimates provided by the manufacturer and are subject to interpretation.
Our long time resident camera expert Wildcat ran the Dahua 4K/X 8MP 1/1.2" sensor thru the paces. Keep in mind this 4K/X camera is incredible.
He had the 3.6mm version and here is the screenshot from 40 feet in the ideal daylight, which based on DORI numbers is the supposed IDENTIFY distance for this camera with the 3.6mm lens and I think most of would agree that this is not IDENTIFY quality, even if digitally zoomed in (thus showing similar to LUX numbers that DORI numbers are estimates and a manufacturer can make it whatever they want and personally I found they need to be cut in half or more during the daytime and even more for nighttime):
I have the 4K/X and it is an incredible camera, but I wouldn't use it for IDENTIFY past 15-20 feet, or half of what the DORI number is.
Here are some of Sony's docs.
www.sony.com
Sony to Release Two Types of 4K-Resolution CMOS Image Sensors for Security Cameras: World's Smallest*1 type 1/2.8 and Enhanced Low-Light Performance Type
Tokyo, Japan — Sony Corporation today announced the upcoming release of two new models of CMOS image sensors: the IMX415 type 1/2.8 4K-resolution stacked CMOS image sensor, which is the smallest of its kind in the world*1; and the IMX485 type 1/1.2 4K-resolution back-illuminated CMOS image...
Last edited: