Photo and video quality is one of the biggest battlegrounds for modern phones. The rear camera lineup of many flagship devices is crammed with three or four lenses and at least one of them is guaranteed to be a telephoto lens if you buy a modern flagship.
The question I see popping up more often these days is, “What good is a telephoto lens on a phone?” Sure, that ticks a box on a spec list, and maybe a 3x or 10x zoom sounds cool for marketing, but is it useful for most users?
Another arms race in modern phones adds further confusion: the megapixel race. Flagship products like OnePlus 9 Pro and Samsung Galaxy S21 Ultra respectively have a main sensor of 48MP and an absurd 108MP. With all of those megapixels, there is plenty of resolution to zoom in after taking the photo and get a range similar to what you would get from a telephoto lens. Isn’t that just as good?
With these questions in mind, I grabbed my Galaxy S21 Ultra and OnePlus 9 Pro and took a few photos with the super high-res main cameras and telephoto lenses, then compared the two. I was surprised with what I found.
Why do you need a telephoto lens?
Before I get to my test results, I want to briefly explain how the telephoto lens is useful in general. The industry has tended to make ultra-wide lenses a higher priority; the Pixel 5 is the best example of this with Google’s move to a wide-angle and ultra-wide setup from the wide angle and telephoto of the Pixel 4 XL. Google’s rationale for the change was exactly what I’ll be examining in my testing: that you can digitally zoom with the main camera to replace a telephoto lens. Ultra wide-angle lenses are also incredibly useful, but it turns out that the telephoto lens has its place as well.
Beyond the basic idea that it’s better to have more options and flexibility in photography, there are many specific use cases for a telephoto lens. Wildlife is perhaps the classic answer, taking pictures of animals without disturbing them or putting yourself in danger with potentially aggressive animals. On a similar note (with that first concern anyway) is to take pictures of your children without interrupting their play or without drawing attention to the fact that you are taking their picture. Using a telephoto lens in these situations can give some of the best shots.
Action shots, whether it’s your kid running or taking photos of a football game, are often best captured with a telephoto lens from a distance. You can actually better follow and capture the action while still focusing on a specific topic. On that last point, finding a subject that you might not have seen is another advantage of a telephoto lens. Sometimes you miss a specific element while trying to capture an entire scene. A telephoto lens will also give you different framing options, as you might have the ability to crop something that was ruining your shot.
Hope this gives you a general idea of how and why you might find telephoto photography useful on your phone. Now let’s see if a dedicated telephoto lens is worth it. Due to a resolution limit on the tool we use for the image comparison slider, I had to reduce the resolution of the shots from the dedicated telephoto sensors, but my comparisons are based on the full images. resolution that are twice those of the samples in the slider.
Do it for the exhibition
One of the most interesting things I encountered while testing was the impact of using the telephoto lens over the standard lens on exposure. The phone makes decisions based on the whole scene it captures. If you do a minor crop it won’t matter, but if you try to simulate 3.3x or 10x zoom it can have a huge impact on the result.
Here’s an example of a shot of a quilt on my porch taken with the Galaxy S21 Ultra’s full 108MP main camera and then with the 10x zoom. I used the same focal point for both. As you can see, the main camera shot is completely blown away from the zoom shot and loses a considerable amount of detail.
Here is a similar example of a garden gnome that is a little less good to wear after winter. Again, I found the exposure sabotaging the shot with the 108MP primary as it pushed the hat to a much lighter color. I also lost details despite this crop offering higher resolution than zoom.
You can clean up some of that with a bit of editing in your phone’s gallery, but that’s extra work. And you still won’t get as good a result as I got from the telephoto lens in terms of capturing the photo as expected. This problem is most noticeable when taking pictures at relatively close range; in both cases, I was about eight to ten feet from the subject. As you’ll see in my next examples, this becomes less relevant when taking longer photos, although it does have other issues.
Zoom is not everything
To put one of my declared use cases to the test, I went to a nearby pond and took pictures of some wildlife, especially herons. It was a pretty clear day so it was full of sun and I was about 30-35 feet from the herons. Here the exposure was less of a problem as the zoomed subject and the entire scene were exposed the same, but I still prefer the telephoto exposure.
One issue I ran into was getting the right focus for shooting from the 108MP and 48MP primary lenses on the Galaxy S21 Ultra and OnePlus 9 Pro, respectively. It’s less annoying on the OnePlus 9 Pro because the 3.3x zoom, at this distance, doesn’t change the scene as deeply, but it was still harder to aim for the herons.
Switching to the Galaxy S21 Ultra, it was not possible to get a photo of the main lens as well focused on the herons as the 10x telephoto lens. The birds are barely visible in the wide angle shot and there are far too many other elements trying to capture the focus.
It’s all in the details
For my last test, I eliminated the problem of focusing the equation by visiting a mural on a local pizza place, assuming that focusing only on the side of a building about 30 feet away would not. would not be a problem for both purposes. I was right on this point, but again I was amazed at the results.
Here is the photo of the OnePlus 9 Pro. I prefer the main lens color result in this case, but there is more grain in this image, which I hadn’t expected.
With the Galaxy S21 Ultra, the colors are closer, but the grain is even more pronounced than with the OnePlus 9 Pro; the 10x optical zoom is by far the sharpest shot.
Why haven’t you tested an iPhone?
In case you were wondering why I left Apple out of this little test, the iPhone 12 Pro and iPhone 12 Pro Max have a telephoto lens, but the big difference is that the iPhone only uses 12MP sensors. So unlike those Android phones with a massive main sensor and 8-12 MP telephoto lens, the iPhone maintains consistent resolution.
The primary remains, by far, the best lens on the iPhone 12 Pro models with its F /1.6, but the drop in resolution is going to be significant to the point where comparing a digital zoom of the primary zoom to the optical zoom of the telephoto lens is irrelevant.
At the end of the line
There’s plenty of room to discuss whether telephoto photography, in general, is needed on a phone. I am very supportive of it because I like both taking pictures of wild animals and I have children who often run at high speed or play sports. There are photos and videos that I took with the telephoto lens of my phones that I just wouldn’t have captured otherwise with a standard lens. However, for others, a telephoto lens may be less relevant.
Having said that, I honestly wasn’t sure how the telephoto lens would fare compared to the huge megapixel primary sensors and was surprised how much better the results are with the real telephoto lens, especially in the case the 10x zoom of the Galaxy S21 Ultra. And while it wasn’t in my testing, another factor to consider is video quality; the digitally zoomed video from the primary lens does not compare remotely to the video output from the 10x zoom if you are trying to capture something in the distance.
If you think one of the telephoto use cases is right for your use, don’t feel like you’re wasting money by going for a high-end flagship to get that larger optical zoom. ; you will be grateful when you get this irreplaceable shot.