The Samsung Galaxy S9+ builds on the S9's single-camera setup by adding the secondary telephoto cam from the Note8. We were introduced to the wide angle cam with the S9, but let's repeat - it's got a 12MP sensor with a pixel size of 1.4µm (Samsung's own ISOCELL for the Exynos model) behind a stabilized variable aperture lens - f/1.5-2.4. The positions are fixed though, you can either opt for f/1.5 or f/2.4 and nothing in-between. There's dual pixel phase-detection autofocus - that's what a portion of each of these large pixels is used for.
The telephoto cam is another 12MP unit, but being a smaller sensor, pixels are 1.0µm on this one. The lens has an f/2.4 aperture (just f/2.4, no variations here) and is stabilized too.
In extreme darkness or for fill flash applications, a single LED flash is there to help. Nothing has changed in this matter since the Galaxy S2 - no dual-tone quadruple-LEDs from Samsung.
The camera does 4-frame image stacking, three times, and then combines the three resulting images to cancel out noise. Samsung promises 30% less noise on all images, which is an impressive achievement right there. Combined with the bright f/1.5 aperture, the results should be cleaner low-light images with less noise and more fine detail.
The camera app UI has changed since the Note8 - but we are not sure it was for the better. Now it's just like Apple's iOS camera app, but with advanced settings - meaning everything is laid out on a rolodex of the available modes.
There is still no dedicated video recording mode and thus a video viewfinder. This shouldn't be an issue for most real-world scenarios, but precisely framing is immensely more difficult without seeing the proper viewfinder before you start recording. You can tap and hold the REC button to see the actual video viewfinder, though, and a hint for that would have been appreciated. Returning Samsung users will know about it, but others will only find it by pure accident.
However, Samsung does have an abundance of powerful features it has to fit inside the UI, and we won't hold that against the Galaxy S9. So, all the important shooting modes are available in the viewfinder, and you switch between those with swipes. The resolution and stabilization options are naturally in the advanced settings.
How does the variable aperture camera work? That's probably the million-dollar question, so we'll start with that. This means brighter aperture versus darker aperture. But it's not about that per se. The depth of field changes, too, something we rarely pay attention to on phone cameras. Having variable aperture opens up some new possibilities, and we'll try to explain the differences without going into full technical mode.
So far, the bright aperture on a mobile camera meant better low-light shots with less noise and more detail. But f/1.5 is quite bright, and the daylight shots may eventually end up overexposed if the shutter speed can't get high enough. However, at least in Pro mode, the Galaxy S9 can increase the shutter speed up to 1/24000s, which means it should avoid blowing the highlights, theoretically at least. That then rules out the potential for overexposure as the reason behind the f/2.4 setting.The main camera at the top: f/1.5 on the left, f/2.4 on the right
Depth of field is another consideration. A relatively large by smartphone standards 1/2.55" sensor with the brightest aperture available is a recipe for shallow depth of field. Again, that is relatively speaking - at smartphone sensor sizes depth of field is pretty huge, which is why we have the whole push for faux bokeh effects to recreate a shallow depth of field. That said, with the right subjects and distances the f/2.4 aperture could bring everything in focus, while f/1.5 might leave some of the subjects blurred.
And the third vantage point is that brighter lenses just tend to be softer at their widest aperture, all other things being equal. Even high-end SLR lenses tend to perform better when stopped down a little, so why shouldn't that apply on a smaller scale, in your smartphone?
So in the end, we have the f/1.5 aperture for improved low-light photos (video benefits a little too), and f/2.4 for sharper images with (a bit) more depth of field in good light. The best of both worlds, so to speak.
In bright light, the Galaxy S9+ produces great-looking photos with plenty of detail, which are also practically noise-free. The engineers have dialed down the sharpening, and we're not seeing the halos that the overly aggressive sharpening produced on the Note8. Dynamic range is also nice and wide, in no small part thanks to the always-on Auto HDR (technically, you could turn it off in settings, but we're sticking with full auto for this test). Those are all taken at f/2.4.
The same holds true for the telephoto camera as well - you won't be sacrificing image quality when you zoom to 2x.
An improvised telephoto shootout ended up pitting the S9+ vs. the Note8 and the iPhone X. Unsurprisingly, the two Samsungs look quite similar, but the iPhone X's shots are noticeably grainier.
We then compared the output from the S9+'s main camera at the two aperture settings - we forced the f/1.5 setting in Pro mode. The first pair of shots illustrates the different depth of field - on the f/2.4 image pretty much everything is in sharp focus, while in the f/1.5 shot the farthest part of the dotted wall panelling is starting to go blurry.
The other two comparisons show improved detail in the f/2.4 images when viewed next to the f/1.5 ones, though we feel there's some extra sharpening applied to the narrower aperture photos to make the difference more pronounced. Software algorithms can't really help with corner softness (the iPhone graffiti), which is typically an issue with large aperture lenses, and we're seeing some of it in bottom corners of the f/1.5 shot, but nothing remotely troubling and certainly better than some flagship cameras we've tested. The f/2.4 images are sharp all the way to the extremes.
We've praised Samsung's HDR algorithms in the past and also enjoyed the live preview of the effect while with other makers you had to wait for the final image. Well, Samsung's HDR now does very little. Or, rather, it's always on, so changing the setting between auto, on and off, doesn't result in dramatically different shots - often not different at all.
In low-light, that f/1.5 aperture proves its worth and the Galaxy S9+ can pick lower ISOs than the competition resulting in less noise. Of course, the competent noise reduction and optical stabilization help too.
The telephoto camera, on the other hand, doesn't really work in low light, and the S9+ in fact zooms in digitally with the normal one. The end results are therefore soft when looked at 1:1 magnification, but still usable at a fit-to-screen level.
We also shot a few quick comparison at night with a set of flagships we happened to have in our pockets at the time. The Galaxy's consistently turned out the sharpest, though the Pixel does have the wider dynamic range.
We didn't think much of the following scene which we shot with the Galaxy S9+ and the iPhone 8 Plus, but it turned up surprising results. We took photos with the normal cameras first, then the telephoto ones, and the S9+ actually did end up using the telephoto cam instead of zooming in on the main one. Not the iPhone. The difference is staggering, and makes us wonder if the light threshold for engaging the main camera in 2x mode might be set too high.
Once you're done examining the real-life samples you can have a look at our Photo compare tool for some studio shots. We've pre-selected the Pixel 2 XL and the iPhone X for the normal camera but replaced the Pixel with the Note8 for the telephoto comparison, due to the Pixel's glaring lack of a telephoto camera. You can, by all means, pick any three phones to compare once you're there.
The Galaxy S9+ puts the two cameras to good use for shooting portraits with artificial bokeh (Samsung calls the mode Live focus). The edge detection is mostly good, though stray strands of hair will confuse it - it's not a marked improvement over, say, the Note8 or the iPhone X/8 Plus.
We compared the S9+'s portraits to the ones from the Note8 and we have to point out that we're liking the S9+'s skin tones a lot more. The Note's overly yellowish rendition of skin may or may not have been the reason for at least one person at the office to part with their Note8. The Pixel 2 XL, on the other hand, favors a more reddish representation.
The S9+'s Live focus mode works quite well with isolating non-human subjects too, and we're particularly impressed by the rendition of our unofficial torture test, a.k.a. aloe plant.
The Galaxy S9+ borrows last generation's selfie cam - an 8MP f/1.7 unit with autofocus. It produces nice-looking images in good light and it's got a Selective focus mode of its own - blurred background portraits with a single camera.