Samsung S20 ultra comparison

Started 6 months ago | Discussions thread
RDM5546 Senior Member • Posts: 1,309
Re: Samsung messed up the implementation

RDM5546 wrote:

Lee Jay wrote:

I tried an S20 ultra. Here's the thing.

The "1x" location is a 12MP downsampling of the main camera's 108MP sensor.

The "2x" location is a 12MP upsampling of the center 3MP of the 1x's downsampling - stupid.

The "4x" location is a 12MP downsampling of the telephoto camera's 48MP sensor.

So, the 4x image is drastically superior to the 2x. The reason they don't sample the full 108MP for the range between 1x and 4x escapes me.

This chart is a 2.7 MP JPEG containg a 4000x3000 image It was taken with the 108MP lens using the S20 Ultra and it's 12M pixels are 3x3 subarrays in the sensor.

1X 4000x3000 image from S20 Ultra

This chart is a 1.7 MP JPEG containg a 4000x3000 image It was taken with the 108MP lens using the S20 Ultra and it's 12M pixels I suspect are 12M single pixels from the middle of the sensor. I suspect this because this is what the image would look like in the center if binning was turned off.

You saying the sensor alway 3X3 bins the pixels resulting in 12MP image that they select the center 3MP and then upsample. Why do think that and where does the documentation support your belief?

I know I can select a 108MP output from this sensor. Then it provides the output from the individual unbinned pixels and I could build circuit to grab the center 12MP with no upsampling. I think this is what they are doing but I have no Samsung document that states this is what they are doing.

I cropped the center of my chart for #1. a 1X 108MP 12000x9000 , #2. a 2X 12MP with the 108MP camera (7mm lens) and #3. a telephoto camera 4000x3000 JPEG using 4X zoom (19mm lens)

#1. a 1X 108MP 12000x9000

1. 1X 108MP camera making a 12000x9000 JPEG cropped leaving the middle. (EXIF data shows 7mm focal length lens)

2. 2X 108MP camera making 4000x3000 binned image JPEG that was cropped in the camera prior to making the JPEG which was then additional cropped to blow up the image in the center.

2X zoom image JPEG made in camera additionally cropped to leave the center. (EXIF data shows a 7mm focal length lens)

Note that image #2 above is not as sharp as #1 above taken with the same lens and camera as #1. However, #2 is not just an in camera cropped version of image #1 but appears to be a 4000X3000 image made from 3000 3x3 binned pixels from the center of #1. That is the most readily explaned reason for the quality of #2 to appear worse than the cropped image of #1 showing the same enlarged image reagon.

3. 4X telephoto camera making 4000x3000 binned image JPEG which was then cropped to enlarge the image in the center

4X zoom image using S20 telephoto camera to make 4000X3000 JPEG which has been cropped (EXIF data shows a 19mm focal length lens)

3. 4X zoom image using telephoto camera to make 4000X3000 JPEG which has been cropped to enlarge the center to roughly the same view as #1 and #2.

From these three images in clear to me than the sharpest images for zooms of 1X to 3.99X may be manually made in post processing in the computer and cropping the image to the desired 1 to 3.99X zoom factor.

Lee Jay was right "Samsung messed up the implementation" is true.  I assume the circuitry may be been simpler and lower in cost to do it their way and it could be to get a quicker devlopment to design the chips but it is no the best way and the best way seems only a little more complex but not very much more expensive in production if a custom chip was being made.

Despite the mess up the camera does take decent pictures at 2X so for many people it may never be noticed that the 4X pictures are sharper than the 2X.  It could have been done better and I am completely happy with my S20 Ultra. It take great images up to 4X optically and  up to 10X digital zoom which is much more than the iPhone 11 Pro which just has a 2x optical and 6X zoom.

More over the S20 Ultra does have a useful digital zoom with reduced quality from 10X  up to 100X provided you hold the camera still, use a tripod or prop the camera against something solid.   Beyond the camera the Smart Phone is very fast with an truly excellent screen and the new 5G communications that is currently limited in the number of cell phones but where it works it is amazing fast.

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