Can I enable pixel binning on Canon PowerShot G1X?

Question

On my camera, a Canon PowerShot G1X, I can select picture sizes from S to L.

Now I wondered, if I select a smaller picture size, that would theoretically lead to more sensor surface per pixel, possibly making the camera perform better in low-light or other 'harsh' conditions.

However, when I try this, I can't notice any difference in behaviour. The end result just looks like a resized version of the larger picture, and there are no differences in shutter speed and ISO to get to that result.

So, it looks like the camera just takes a large picture and then downscales it, which was against my expectations (or at least against my hopes).

Pixel Binning

The term that I think I am looking for is Binning also known as CCD Binning, Data Binning or Pixel Binning.

It certainly has advantages over downscaling by software, because it makes more efficient use of the hardware (faster reading, better noise reduction).

I think the answers below don't really answer my question. Neither do the answers of the supposedly 'duplicate' of this question, although the answer by mattdm came closest by at least suggesting that a camera might support this 'hardware-level binning', which allowed me to continue my search.

So far I couldn't find evidence that the Canon G1X supports binning, so I'm afraid it does not. But if someone know if it does (or maybe knows a hack or trick to enable it), please let me know. Previously I had a Canon PowerShot SII, and there was a way to install 3rd party firmware to unlock extra features. Maybe something like that is possible for the G1X as well?

Answer 1

I do not know your specific camera model, but I think in general that the S-to-L scale refers to the size of the compressed jpg image when stored on your camera memory card.

In other words, your camera takes a raw picture at most of its possibilities and then compresses it in jpg format to save space on disk. Jpg is a lossy format, it means you can compress more at the cost of losing some information compared to the original image.

When you choose S you lose more details but get smaller files for your photograph; when you select L you waste some space but get finer details.

Beware that, given today's technologies, you probably can notice the data loss on specific pictures (i.e. when there are very fine details) or at very high zoom level.

Answer 2

Your conclusion is partially correct.

You will get some noise reduction as part of the downscaling process. But it will come from the same image and camera settings (shutter, aperture, ISO) won't be different for the S and L modes.

It's also likely that the S mode is using a lower quality setting on the JPEG encoder, which will negate some of the gains you might make in noise reduction.

There are cameras like the Nokia pureview phone camera or some of the early Fuji DSLR's which benefit significantly from downscaling but are also specifically designed to do so.

If you wanted to try to replicate what you think the camera is doing you can dial in -1.0 EV of exposure compensation - that would affect how the shutter & aperture are set and underexpose it. You can then shoot in the highest resolution available and see if you get a better result by 'pushing' or lightening it in post-processing.

Answer 3

There are many ways your camera might try to create a smaller image file, among them higher JPG compression. What exactly is going on inside of your camera is the manufacturer's secret.

My assumption would be that the camera takes a raw image as usual and then just downscales it using a cheap (in terms of processing cost) rescaling algorithm. This is usually nothing that you have any influence on. The resulting image might look slightly better but this is largely due to the noise reduction achieved via downscaling.

Because of this I usually avoid taking pictures at a resolution lower than the sensor resolution. Instead, I select the maximum resolution or, if possible, RAW format. Afterwards, you can then edit the picture on your computer and fine-tune the downscaling and compression options, maybe even apply some more noise reduction before producing the end result.