SL2 pixel density

[IJGRAY]

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When comparing the pixel density of the SL2-S compared to the SL2 it is noted that the  lower maximum density of the SL2-S is half that of the SL2. Consequently this means that the size of each and every pixel is twice as large as those on the SL2 and a larger pixel size means better performance in lower light photography. Thus they argue that the SL2-S may be a better choice for some. 

What I don’t understand why nobody points out that you could at the same time use an SL2 but select a lower density setting if you so desire. I am led to believe that most cameras even the cheapest allow you to alter the pixel density. I often select the lowest density to send files to people.

Am I missing something here ? Sony in particular make different camera version in their A7 range to specifically accommodate this factor.

My obvious question is - Why not have a high density camera but select the lower density option when appropriate instead of buying a lower density camera to make better low light images.

 

 

 

[jaapv]

Welcome to the forum  
You are confusing pixel density, which affects the physical size of the pixels (sensels) on the sensor, with resolution, which is the number of pixels, and pixel binning, which is combining the output of adjacent pixels..
I think that you are referring to downsizing, which uses a defined algorithm reduce the number of pixels in postprocessing. In that case the result depends on the algorithm chosen.

In-camera you can set the JPG output to a lower resolution, but that will impact image quality negatively.

In each case you will get a different result.

[frame-it]

31 minutes ago, IJGRAY said:

but select a lower density setting if you so desire. I am led to believe that most cameras even the cheapest allow you to alter the pixel density. I often select the lowest density to send files to people.

how do you do this?

[Stuart Richardson]

You are correct, however, that you can just downsample the file from the 47mp camera in photoshop, and it will minimize the appearance of noise. People tend not to do this, and just look at 100% and declare the lower resolution camera better at high ISO. I believe that when compared at the same same resolution, the SL2S still has slightly better high ISO performance, but the difference between it and the SL2 is not as dramatic. Personally, I find the gain in resolution at low ISO more important than the gain in noise characteristics at high ISO, but for photographers who do not print large, or who have both cameras, they may feel differently.

[Slender]

4 hours ago, IJGRAY said:

.....Consequently this means that the size of each and every pixel is twice as large as those on the SL2.......

Nope, quite not.

6 μm pixel pitch on the SL2s.

4.3 μm pixel pitch on the SL2.

The math?

Assuming pixels are square, take the large side of the SL2 (8368 pixel) and divide by the one from SL2s (6000) = 1.39466667.

The pixel pitch of a FF 24MP sensor being 6 μm divide by 1.39... tada you get to the spec listed 4.3um of SL2 47.3MP sensor.

 

If you want to OVERSAMPLE (downsampling throws pixel away, oversampling merges them), the effective image size reduction in photoshop, from a 8368 x 5584 pixels file size down to a (perfect) 24 MP = 6000x4000 pixels, you average about 70% of the original image height and width.... whilst effective resolution is halved. Makes for crisper images with a fine or non-existent grain.

Let us not forget the cousin S1R sensor got the highest ever score in DXO for full frame sensor. When used well, it works wonders.

Edited January 9, 2022 by Slender

[Virob]

3 hours ago, Slender said:

Nope, quite not.

6 μm pixel pitch on the SL2s.

4.3 μm pixel pitch on the SL2.

The math?

 

 Pitch and area are two different things. All else being the same, a (square) pixel of 6x6 micron = 36 um2 vs 4.3x4.3 = 18.5 um2, almost exactly twice the light gathering capacity.

[Slender]

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😅 mixed my brushes there, too. Thank you,

For sure I know we have great tools, we should just honor them and our forebearer photographers by using them without thinking too hard about technicals stuff.

[SrMi]

Welcome to the forum. The best thing that can happen to you on this forum is that you are wrong, because then you can learn something. There are many LUF members who are very eager to correct others ... talking primarily about me .

[IJGRAY]

On 1/9/2022 at 2:20 PM, Slender said:

Nope, quite not.

6 μm pixel pitch on the SL2s.

4.3 μm pixel pitch on the SL2.

The math?

Assuming pixels are square, take the large side of the SL2 (8368 pixel) and divide by the one from SL2s (6000) = 1.39466667.

The pixel pitch of a FF 24MP sensor being 6 μm divide by 1.39... tada you get to the spec listed 4.3um of SL2 47.3MP sensor.

 

If you want to OVERSAMPLE (downsampling throws pixel away, oversampling merges them), the effective image size reduction in photoshop, from a 8368 x 5584 pixels file size down to a (perfect) 24 MP = 6000x4000 pixels, you average about 70% of the original image height and width.... whilst effective resolution is halved. Makes for crisper images with a fine or non-existent grain.

Let us not forget the cousin S1R sensor got the highest ever score in DXO for full frame sensor. When used well, it works wonders.

Thanks for all the replies but the point I am trying to get over is this - On a SL2 when you select the 24M option does this convert your camera into a camera with bigger pixels Similarly if you select the 12M option does it make the pixels even bigger ?

 

 

[jaapv]

The pixels remain the same size, they are physical spots on the sensor They cannot shrink or expand.
The only thing that happens is that the camera applies a digital interpolation to arrive at the pixel count of a virtual camera with a sensor containing 24 MP.
The result is wholly dependent on the algorithm used. Normally some noise is eliminated, motion blur performance may be minimally improved and some detail lost, that is all. And the files will be smaller.
A native 24 MP camera will perform marginally better for the simple reason that one pixel will have more active surface than a number of pixels occupying the same surface area.

[Virob]

It must get even more complicated considering the Bayer filter on top of the sensor. 

[jaapv]

It is indeed a factor, the interpolation to get a colour image loses at least 30% of the native resolution. That is the reason why monochrome sensors outresolve their Bayered counterparts.