Does a 4mp sensor become more light sensitive if set to record at 2mp?

[Murphy625]

I understand that the size of the pixels on the sensor basically determines their low light sensitivity performance. The larger the pixel, the more photons which hit it.

So what I'm wondering is, if a 4mp camera is set to a 2mp output, will the sensor's low light performance increase any? I'm wondering if this causes the camera to use 2 of the sensor's pixels instead of just one to create the scaled down image.. or if its just a software trick that discards the extra information.

Thanks,

 

[Wildcat_1]

No, your choice of resolution (lowering from maximum supported) does not/cannot change the underlying sensor’s physical capabilities. This is why manufacturers state 1 set of min illumination specs etc.

HTH

I understand that the size of the pixels on the sensor basically determines their low light sensitivity performance. The larger the pixel, the more photons which hit it.

So what I'm wondering is, if a 4mp camera is set to a 2mp output, will the sensor's low light performance increase any? I'm wondering if this causes the camera to use 2 of the sensor's pixels instead of just one to create the scaled down image.. or if its just a software trick that discards the extra information.

Thanks,

 

[erensfd]

I think all the camera does in this case is to down sample the original image to the selected lower resolution. So my guess would be no change in low-light performance.

 

[Murphy625]

Seems like a waste of resources. If you have an 8mp camera with a 1.62um pixel size, then turning the resolution down to 2mp should allow you to combine 4 of the 1.62um pixels for a total size of 3.24um for each pixel.

Is there some kind of hardware architecture limitation involved that prevents doing this?

Seems to me, if they designed a camera to do this, you could have that big beautiful 8mp picture during the daytime and tone it down at night to 2mp for that super night vision performance.

Seems like they're ignoring what could be a really cool feature.. so I have to wonder why.

 

[guykuo]

Not exactly how it works, but this should make it easier to understand....

Think of the pixel sensor as a conductive plate that needs enough electrons popped onto it by incoming photons to get a voltage signal high enough to detect. If the plate is 4 times larger, it can gather 4 times as many photons pumping onto that larger plate. It gets up to detection threshold four times easier. A smaller plate still needs a same number of electrons to reach threshold as a larger plate, but you are gathering fewer photons/plate due to the smaller area. Using four smaller pixels doesn't link the four plates into one collector.

 

[Murphy625]

Not exactly how it works, but this should make it easier to understand....

Think of the pixel sensor as a conductive plate that needs enough electrons popped onto it by incoming photons to get a voltage signal high enough to detect. If the plate is 4 times larger, it can gather 4 times as many photons pumping onto that larger plate. It gets up to detection threshold four times easier. A smaller plate still needs a same number of electrons to reach threshold as a larger plate, but you are gathering fewer photons/plate due to the smaller area. Using four smaller pixels doesn't link the four plates into one collector.

That makes sense. Thank you.