Looks like we needed something to be outraged about.

A flurry of stories have been published, claiming deceit on the part of OnePlus. The zoom on the OnePlus 7 Pro camera is a LIE! It’s NOT really a 3X zoom! PITCHFORKS! TORCHES!

Except it is. It’s exactly what OnePlus advertised it to be. In fact, it’s a little better than what they advertised. You get a little more than what they listed on the spec sheet. The main thing OnePlus is guilty of is a clumsy execution, which we shouldn’t be too surprised about. This company is regularly “charmingly clumsy”.

We’ve got a lot to unpack here.

First of all, Very few phones really have a ZOOM lens.

A zoom lens is where the lens moves pieces of glass around to change the field of view. On a traditional camera, you’ll see how the lens telescopes in and out of the camera body. Samsung flirted with this on the Galaxy Zoom and K series phones back in the day. It’s good for a point and shoot camera, but not great for a phone that lives in your pocket.

After that, a few phones have tried hiding the lens movement internally. The Asus ZenFone Zoom had a sliding internal lens, and it was terrible. Today we have the Huawei P30 Pro, which uses a periscope design, but does NOT slide lens elements around. It’s a higher quality “zoom”, but it doesn’t really zoom.

And that’s it.

Every other phone with a “Zoom” accomplishes a change in view by switching between two or three separate sensors paired with different focal length lenses. The lenses don’t move. The glass doesn’t shift. These phones don’t really “Zoom” in a traditional sense. Software slides the image around, masking the transition between two completely separate cameras.

You probably already understand that, but it’s important to reiterate, because the multiple sensors on the back of your phone are not all the same. The main “standard” view is always the best sensor, and the sensors responsible for wider and narrower views are always poorer and smaller.

Why do we use smaller sensors? Cost, space, and optical physics.

In photography we typically describe field of view as it relates to a 35mm film frame paired up with a specific focal length of lens. We use math to describe that view, and when the sensor size changes, we multiply the difference in size until we arrive at an equivalent to 35mm photography. That’s called a Crop Factor.

Take a full frame camera, like a Canon 5D. It uses a large sensor which is very similar to a 35mm film frame. Put a 50mm lens on that camera, and photographers know what that combo looks like really well. It’s a very standard photography field of view.

Take that same lens and put it on a camera with a smaller sensor. It will appear more “zoomed in” because the smaller sensor will use less of the lens. It will “crop” the corners of the lens. This is different than digital zoom.

An APS-C sensor is about half the size of a 35mm full frame sensor, so it’s crop of 1.5X can be multiplied by the focal length of the lens. A 50mm lens on an APS-C sensor will look similar to a 75mm lens on a full frame camera.

This is what our phones do too. They just do it A LOT more.

If a phone advertises a 26mm EQUIVALENT lens for the main sensor, it WILL NOT have a 26mm lens.

The OnePlus 7 Pro main sensor is paired with a 4.75mm lens. That’s a super wide lens, but the sensor is ridiculously tiny. That combo (a 5.5X crop factor) produces a similar field of view to what a 26mm lens will achieve on a full frame camera.

For most phones with a zoom sensor, the zoom sensor is smaller, so the manufacturer can benefit from the higher crop factor. The lens isn’t twice the focal length. There’s an optical “trick” at play.

On the LG V40, the main sensor has an EQUIVALENT of a 25mm lens, and the zoom is the EQUIVALENT of a 50mm lens. The main camera lens is REALLY a 4.23mm lens. The zoom is REALLY a 5.88mm lens. Only a 1.6mm difference, which means the zoom SENSOR is SIGNIFICANTLY smaller than the main sensor.

Our phones play this trick with EVERY sensor. A real 5mm lens would be a fisheye lens on a full frame camera. We have to stretch and correct for that optical distortion so a phone camera LOOKS like the equivalent view of a more standard lens.

Complaining about optical distortion or field of view is disingenuous if we don’t acknowledge that ALL phone cameras employ optical correction of some kind. You don’t want to see the true optical effect of a 5mm lens on your phone, because it would look comically barrel distorted. Complaining that you don’t get the “true” optical effect of a “3X zoom” when talking about a phone lens is foolish.

A quick tangent:  Digital Zoom on the Pixel 3a.

Digital zoom is significantly different than crop factor. Let’s use the single lens on the Pixel 3a as an example.

When you zoom, the image gets blurrier faster. When you look at the resolution of the zoomed photo, it’s the same resolution as the full field of view. The Pixel is making up resolution, faking pixels that don’t really exist. That’s digital zoom. It’s not an optical effect. Software is making up the difference.

This is what OnePlus got tagged for on the OnePlus 5.

That phone had a proper 1.6X zoom off the lens, and used software to upscale the image to a 2X zoom. That was somewhat deceitful. They lazily advertised a 2X zoom with a 20MP sensor, and in the OnePlus 5 keynote, they glossed over the “Smart Capture” trick. Optical zoom and “multi-frame” technology would create the effect of a true 2X zoom, but it was just another way to “software up-scale” and catch up to Apple.

The OnePlus 7 Pro is the opposite situation.

OnePlus advertises the equivalent of a 78mm lens at 8MP, which is three times the focal length of the main sensor at 26mm equivalent.

That’s exactly what you get. No tricks. No software cropping. No up-scaling an image in post. You really get an 8MP image, with an equivalent field of view which is three times the equivalent field of view from the main sensor.

OnePlus did this in a clumsy way, but there is no deceit.

OnePlus is using a 13MP camera sensor, but only using the center 8MP of that sensor, to pair with the focal length of the lens, to create the field of view advertised. They are delivering EXACTLY what they promised.

This is functionally no different than if they had used a smaller 8MP sensor with the same lens. Restricting the sensor surface area creates a narrower field of view. This is all true optical performance.

Why do this? Why use a 13MP sensor?

It’s hard to say. It is clumsy.

If I had to guess, the image compromises around 2X zoom didn’t make for a compelling marketing bulletpoint. In my experiences, the zoom sensors on most phones are severely compromised compared to the main sensor.

On an iPhone XS, you will RARELY actually use the zoom sensor. It will almost always crop in the image from the main sensor, unless you are in PERFECT outdoor sunlight. Indoors, or at night, the main sensor is so far improved over the zoom sensor, you will get a better image with a “fake” digital crop and software upscale.

The main sensor on the OnePlus 7 Pro is a huge step above the zoom sensor. It has significantly more surface area and a ton more resolution to crop with. Going from 26mm to 52mm (2X zoom) is WAY better on the main sensor, than using the full 13MP sensor at an equivalent of 57mm.

There’s also something to be said for using the 13MP sensor, as it’s probably a higher quality sensor than any true 8MP sensors. Smaller, lower resolution sensors are often reserved for crap selfie cameras.

This gives OnePlus some flexibility. It can still use that larger resolution for something like Portrait Mode. It’s OK in Portrait Mode if corner sharpness or details are a bit soft. The whole point is to blur a large part of the frame with software blur.

By contrast, when you zoom, you’re likely looking for image clarity, where the phone is only using the sharpest part of the center of that lens.

What sucks here is the blurring of marketing speak, consumer expectations, and physics. Crop factor is a confusing concept, and we’ve been playing fast and loose with terms like “zoom”.

“Zoom” on its own is somewhat irrelevant. If we’re concerned about optics and performance, then we need to discuss equivalent field of view, and how that compares against the true sensor size and focal length.

Without context it looks like a lie by OnePlus, but it’s only a little different than what every other manufacturer does.

Looking at the camera performance, it looks like OnePlus has made the correct set of compromises to deliver the best output at each equivalent focal length. If images up to 75mm (2.9X zoom) look better from the main sensor, why would you want to use a smaller sensor in that range? If anything, I wish OnePlus would use the main sensor even farther into the zoom range.

It’s clumsy, but it’s not deceitful. There’s no controversy here.

***UPDATE on Focal Length***

Several folks have shared gifs like this one below, as to why we should be concerned about the difference in reporting “true” focal length as not “3X Zoom”.

This is horrifically disingenuous, and muddies the waters tremendously. What you see in the above gif, is the effect of focal length changes ON THE SAME SENSOR, and the main reason you see this warping is because of the change in distance between the camera and the subject.

As we’ve already established, this is not what happens on phones.  Zoom on a phone is achieved by balancing small changes to the focal length against using a completely separate, smaller image sensor to magnify that change.

Remember, on the LG V40, there is only a 1.6mm difference between the standard and zoom lens. On the OnePlus, there is only a 2.2mm difference in focal length. Do we really think those differences in focal length would achieve ANYTHING like the image differences alluded to in the above gif? No. We do not.

Anyone trotting out an argument that we’re somehow being cheated of the “proper” zoom effect on a OnePlus is either unfamiliar with the physics of lenses, or is lazily reporting on something they know will generate outrage traffic.