New Member: A question about sensors and megapixels

[Panama Hat & Camera]

What happens in the sensor of a camera when it works with an image size smaller? For example to set a 12 megapixel camera at 6 megapixels.

[Donald]

Antonio - As I advised in the New Member Introduction section, I have moved your question into this section of the forum and created a new thread. Hopefully more members will see it here and be able to reply to you.

[JonathanC]

There are several ways that its done.
1) If you use only part of the sensor (if you do video in a DSLR or use a crop sensor lens on a full frame camera) it just ignores the edges.
2) If you select a lower resolution it interpolates the pixels from standard size pixels in software.
3) If you have a specialist camera, such as those used for astrophotography, it can "bin" the pixels. That is to say that the input from the pixels is added so that the camera has lower resolution but higher sensitivity. This "binning" can be done by adding two adjacent pixels, a grid of four in a square pattern or rectangular groups up to 4X4 (usually).

I think.

[Dave Humphries]

What happens in the sensor of a camera when it works with an image size smaller? For example to set a 12 megapixel camera at 6 megapixels.

Hi Antonio,

To be pedantic, I'd have to say that nothing is happening in the sensor, the pixels will be 'got rid of' in the image processor chip and the only benefit is likely to be smaller file size. years ago, this possibly mattered, now it doesn't, because memory is cheap and card sizes are nearly 10x bigger than a decade ago. I think the fact that most cameras still offer this feature is a waste of time these days.

I have always shot at the highest resolution the sensor allows, it provides more leeway for cropping and when I do want to downsize, I can choose which method is best.

Oh, please forgive my bad manners, I forgot to say "welcome to the CiC forums".

All the best,

[Panama Hat & Camera]

Gentlemen, thank you for your attention. Now, I have two different answers to the same question and the worst is that I think both answers may be correct because the camera manufacturers may use different ways to adjust the image size. Someone could help solve my doubt?
Antonio.

[Colin Southern]

What happens in the sensor of a camera when it works with an image size smaller? For example to set a 12 megapixel camera at 6 megapixels.

It depends on the make/model of the camera.

[jcuknz]

I don't know but I thought the idea of binning was to reduce noise when working at high ISO?

If you are running out of storage space and don't have a replacement card I suggest you should increase the compression rather than reduce the resolution in jpg or RAW>jpgFINE for those last few shots.

[Panama Hat & Camera]

The question is just noise reduction. I am user of a superzoom camera and the weakness of these cameras (because of small sensors) is the presence of noise when using ISO above 400. I'll do some testing to see if reducing the size of the picture causes a reduction of the noise level.

[Panama Hat & Camera]

Donald, thank you for moving my question to the area of the forum. I'm new to CiC and am learning to navigate the site.