With the release of Samsung Galaxy S21 we ended up with 3 generations of Galaxy phones at home, the S9, the S10+ and the more recent S21. I thought it would be a good idea to run a quick comparison regarding the camera performance of these three devices. Note that the S9 was release in March 2018, S10+ in March 2019 and S21 in Jan 2021. To have an idea about the official camera specs I've attached a comparison from gsmarena bellow.

The comparison is based on a series of very basic day-to-day shots (in "auto" mode) we all take with our phones and the images are available at their full resolution if you click on them. They appear from left to right in order of device release date, from earliest to latest (i.e. S9, S10+, S21). Let's start.

Example 1 (outdoors)

All three look about the same, with some differences in exposure.

Having a closer look, I think that in S21 (and probably s20) they decided to move away from the over-sharpening approach followed in S10+ which produced weird artifacts like the way number "4" is captured, and the text in "want to drive this bus?". The photo from S21 seems to have more noise in some areas e.g. the red colour on the bus is a bit grainy.

Again, less sharpening, less contrast and more detail in S21, in general I'm not a fan of the post-processing applied here, it looks less like a photo and more like a drawing.

Example 2 (outdoors)

Similar setup as in the previous example, negligible differences between the three cameras. The same comments as before apply for the sharpening.

Example 3 (indoors)

The photo from S21 seems to have a wider dynamic range and better exposure.

In the following cropped section the result from S21 is significantly better compared to S9 and S10+, mainly in terms of noise level and detail.

Example 4 (zoom 2x)

Decided to compare them at 2x zoom as S10+ has 2x optical zoom and S21 has a hybrid 3x zoom (using 1.1x optical zoom).

The lack of optical zoom in S9 is obvious in this comparison. The hybrid zoom in S21 seems to produce a more detailed photo with lower levels of noise.

Example 5 (Outdoors wide-angle)

In this example the wide-angle camera is used on s10+ and s21. I've also taken the same photo with s9 to have it as a reference point (s9 doesn't have a wide-angle camera/lens).

The image from S21 is definitely sharper than the S10+, without any unwanted artifacts caused by post-processing. So far in the comparison I think it's the most obvious improvement brought by S21.

Example 6 (Low light indoors)

The "night mode" was enabled in all three devices for this photo and there's also a fourth image coming from a Nikon D3400 DSLR to make the comparison a bit more interesting.

The S21 does a good job in this scenario as well, with good detail and very low noise (probably applying more extreme noise reduction during post-processing, however without affecting the image detail).

To be able to take a photo without flash with the D3400 I had to use a pretty high ISO (128000) which caused a lot of noise in the photo. With some post-processing it could look better but it's still not a great image. It's impressive that modern smartphones can perform better than DSRLs in scenarios like this (at least "handheld" :D).

Example 7 (1080p Video)

Finally, to make the comparison a bit more thorough I've included two sample videos taken with the main camera of each device. In one of them I'm walking while recording to capture some of the image stabilisation properties of the devices. In hindsight, I could have captured 4k video with all three devices, but apart from the lower resolution, 1080p should be ok to get an idea.

Verdict

The more recent S21 seems to be the best performer in this test. However, the differences between the S10+ and S21 are minimal and even comparing with the 3-year older S9, the differences are not massive. Going from S9 or S10 to S21 just for the minor camera improvements wouldn't make a lot of sense. Nevertheless, I really enjoy other features of S21 so far, like the 120hz refresh rate of the screen which really makes a difference in comparison to S9/S10 (note though that it was also available in s20 so not an exclusive new feature of S21) and the faster cpu.