Dropping resolution from 4MP to 2MP on SD1A404XB

CanCuba

CanCuba

Known around here
Dec 9, 2020
1,267
4,029
Havana, Cuba
I am anxiously awaiting the delivery of a SD1A404XB tomorrow. First PTZ so it's very exciting to have a new toy arriving.

Having done some reading, it seems that Dahua is using the same (or at least the same size) sensor 1/2.8" as the 2MP model of the same camera (SD1A203T).

This camera will be running face detection 24/7 and be triggered by other cameras. I'm more interested in the quality of FD at night. I have decent lighting (120W LED flood) that I will be replacing with better lighting (500W LED flood) in a couple months. I'm hoping to be able to use night colour instead of IR until I get the new flood light.

My question is: Will I have better night vision at 2MP than 4MP with this camera?
 
I have this same camera that I'm using for my front porch. The 2MP version would give you better night vision.
With plenty of light though, the 4MP does just fine, in my opinion.
 
  • Like
Reactions: CanCuba
CanCuba said:
I am anxiously awaiting the delivery of a SD1A404XB tomorrow. First PTZ so it's very exciting to have a new toy arriving.

Having done some reading, it seems that Dahua is using the same (or at least the same size) sensor 1/2.8" as the 2MP model of the same camera (SD1A203T).

This camera will be running face detection 24/7 and be triggered by other cameras. I'm more interested in the quality of FD at night. I have decent lighting (120W LED flood) that I will be replacing with better lighting (500W LED flood) in a couple months. I'm hoping to be able to use night colour instead of IR until I get the new flood light.

My question is: Will I have better night vision at 2MP than 4MP with this camera?
Click to expand...

Hi @CanCuba

4MP and 2MP sensors are different chips.

Thus taking a 4MP sensor camera and down res to 2MP in settings:

no, the physical size of the pixel on the sensor is not changing - so unless there is some magic firmware that combines 4 pixels into one virtual pixel .. you are going to get a crop of the sensors to the lower resolution.
 
  • Like
Reactions: CanCuba, fenderman and sebastiantombs
Downrezing a camera does not work - It is still using the 4 million pixels - the camera doesn't change the "pixel resolution screen" on the camera when you go from 4MP to 2MP. The sensor still needs 2 times the light going from 4MP to 2MP, so the native 2MP 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 4MP isn't performing or wouldn't perform well at night, then it is better to go with the 2MP.

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.
 
  • Like
Reactions: CanCuba and sebastiantombs
EMPIRETECANDY said:
The 4mp also is working bit good at low light place, 2MP at deep dark place will be some better than 4mp.
Click to expand...

I'd say I have "medium" light using a solar LED reflector. Going to run some tests once it's installed and post the results here. From what you're saying, I should be able to get away with 4MP. Face detection is critical for me as robberies are a growing issue in my area.
 
mat200 said:
Hi @CanCuba

4MP and 2MP sensors are different chips.

Thus taking a 4MP sensor camera and down res to 2MP in settings:

no, the physical size of the pixel on the sensor is not changing - so unless there is some magic firmware that combines 4 pixels into one virtual pixel .. you are going to get a crop of the sensors to the lower resolution.
Click to expand...

Thank you. Being relatively new to this, I'm still in the "more MP is better" mode. But this forum has tonnes of information and I'm learning a lot.

Already planning to replace some cameras (all of them now are 2.8mm) with other cameras with a longer focal length in more critical areas.
 
  • Like
Reactions: Lincos, sebastiantombs and mat200
If you haven't seen this thread, it is a must to get over the more MP is better mode LOL:

The Importance of Focal Length over MP in camera selection

At the urging of several folks here, I created a thread to show the importance of focal length and how focal length can be more important than megapixels (MP). I mentioned some of this in the post regarding The Hookup’s latest video demonstrating different cameras, including one sold from a...
ipcamtalk.com ipcamtalk.com
 
  • Like
  • Love
Reactions: Lincos and CanCuba
wittaj said:
Downrezing a camera does not work - It is still using the 4 million pixels - the camera doesn't change the "pixel resolution screen" on the camera when you go from 4MP to 2MP. The sensor still needs 2 times the light going from 4MP to 2MP, so the native 2MP 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 4MP isn't performing or wouldn't perform well at night, then it is better to go with the 2MP.

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.
Click to expand...

Excellent information. Thank you.

I don't have a lot of street light but the LED reflectors (solar powered which are so easy to install (no excessive wiring, etc) and a one-time cost) provide decent light into the street.

The local thieves now know I have cameras covering my entire perimeter and avoid the sidewalks in front of my house. But they don't realize the coverage I have and that I've pointed the cameras up a bit to cover the street.

I've learned a LOT from posts from people such as yourself, Empire, Wildcat, etc

Over the next year, I'm going to buy another PTZ and replace some of the 2.8mm cameras with varifocals.

And even more lighting. I want daylight conditions at night into both streets (I have a corner property) to 1) keep criminals away and 2) be able to run face detection 24/7 on anyone walking by.

Thanks for your tonnes of posts, not just this one, as they've helped me understand security cameras, the technology behind them and their effective deployment.
 
CanCuba said:
Hoping to be able to use colour at night. Barring that, the IR distance will be enough to get to the other side of the street (according to specs).

I'll be doing some testing to see what works.
Click to expand...

I have non color vue hikvision cameras as well as cheap amcrest ones I bought from the zon. I have color at night in most of my yard 2-3 hrs after sunset due to the amount of solar LED lighting I have around the garden and house (mounted on my gutters).
 
CanCuba said:
Hoping to be able to use colour at night. Barring that, the IR distance will be enough to get to the other side of the street (according to specs).

I'll be doing some testing to see what works.
Click to expand...

Most of us have found after you take the camera off default settings so that you can actually freeze frame and get a clean image of a perp, the IR distance spec should be cut in at least half if not 75%.
 
  • Like
Reactions: Lincos, CanCuba and sebastiantombs
wittaj said:
Most of us have found after you take the camera off default settings so that you can actually freeze frame and get a clean image of a perp, the IR distance spec should be cut in at least half if not 75%.
Click to expand...

Is that the lens/sensor or the onboard IR? Once I have the camera and new LED reflectors (500+ watts) installed (it's on a high-tech testing rig right now), I may end up using IR. But I'm thinking that a couple 500W LED reflectors (about 30k lumens each) will be enough to use colour.
 
You must log in or register to reply here.
Top Bottom