Samsung made huge strides in camera quality with the Galaxy S20 series, to the point where in many situations the S20 Ultra is taking photos directly comparable to the Pixel 4 XL. Putting aside little quibbles around the details of how the photos look, I'm really loving what this camera is capable of, and I don't feel like I'm using an inferior camera like I did with the S10+.
I think the Galaxy S20 Ultra's camera is great, and its zoom capabilities are a big part of that.
And it's not just about the 108MP main camera; a big part of my enjoyment is the quality of zoom shots. I've had my Galaxy S20 Ultra for a couple of weeks now, and I really enjoy incorporating zoom shots into my regular use of the camera. But something I figured out very quickly is how little I want to use the super-long zoom options. After my testing period, where I specifically found situations to compare the various zoom levels, I haven't once had the desire to zoom past 30X. And rarely even hit 20X.
Why's that? Well, because the quality of the photos after 30X is trash. There's no sugar coating it. Once you go beyond 30X, the deterioration in quality is so rapid that it becomes not worth the trade-off. Shooting at 30X and getting a half-decent photo is possible if the scene is extremely bright and you have a steady hand or tripod; 50 or 70X produces "a photo" and nothing more. 100X is frankly laughable. There isn't a single photo I have taken at 100X that is worth anything more than proving that it can take a 100X photo, let alone be a photo I'd actually want to save. Each and every one is blotchy and soft, with fidelity along the lines of a watercolor painting from the 1800s.
Source: Andrew Martonik / Android Central
If you just think about the physics of it, it's no surprise photos after 30X are garbage.
And if we just think about the physics of it, the low quality makes sense — and is basically impossible to overcome. Yes this is a gigantic camera sensor by smartphone standards, and the 4X optical zoom already required a huge camera bump and periscope lens arrangement just to make it fit. But when all you have is 4X optical, the amount of digital cropping required to make it all the way to 30X, to say nothing of 100X, makes it so you can never take a high-quality photo. If Samsung put another 108MP sensor behind this 4X lens it'd help a little, but it still wouldn't make 100X feasible. These photos are always going to be bad.
The unfortunate thing here is that the S20 Ultra's zoom system is really valuable. The default "telephoto" zoom level of 5X takes shots with almost no loss in quality compared to the main camera, including in low light scenes, and actually has great natural bokeh for portraits. It can take excellent shots at 10X that are unmatched by any other phone. It's even capable of getting really good pictures at 15X, depending on the conditions. I've taken dozens of wonderful zoom photos, as you can see below, but not a single one was taken past 10X.
Source: Android Central
Samsung let its marketing message take precedence over the phone's actual capabilities.
The issue here isn't that the entire zoom system is worthless. The problem is Samsung's marketing message taking precedence over the phone's actual capabilities. If Samsung would've stopped the camera's zoom at 30X, I'd have zero complaints; heck, it could've even topped out at 50X and I wouldn't make a point out of this. The problem is, it didn't. It printed "SPACE ZOOM 100X" on the camera housing, and lets you jump straight to 100X in the camera app. Even though nobody should bother using it.
But "100X" looks a lot cooler in an advertisement. "100X" looks cool printed across the back of the phone. Not "30X" — so Samsung shipped it. Samsung didn't just over-promise by a little, it over-promised by a ridiculous amount. And it unequivocally under-delivered on the zoom capabilities of the Galaxy S20 Ultra. And it's a shame, because the zoom really is useful, and S20 Ultra owners will enjoy it — they're just going to be disappointed that the phone doesn't at all do what it claims to be capable of.