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We live in the USB era. Almost everything that connects to our computer these days goes through an interface so ubiquitous that the word “universal” appears in its name – the Universal Serial Bus. USB has been a godsend in many ways, replacing all manner of connectors encountered in earlier technologies.

Simple, right? Well, not so much.

The problem with USB-C

Standards are great. Except when they’re not. USB-C, introduced in 2014, is the closest thing we have to “one plug to rule them all.” The problem is that despite supporting a wide range of standards, all USB-C cables look pretty much the same. A cable that supports the latest and greatest technology can look identical to a dumb charging cable. 

And, as if things weren’t complicated enough, ThunderBolt has used the same-shaped connector since ThunderBolt 3, despite being vastly more capable than standard USB.

Which is why I recently found myself staring into the abyss – in this case, a drawer in my office – trying to figure out which of the dozen or so USB-C cables in front of me was the right one to use with an SSD. I doubt I’m alone in this, and I suspect most photographers or content creators have a similar drawer or box full of cables. That’s the exact problem a Mac app called WhatCable is built to solve.

Mitchell Clark

Hoping for the best, I grabbed a cable that looked new, plugged it in, and got on with finding the photos I needed. It seemed to work, so I didn’t stop to check whether I was actually getting the fastest speed the SSD could support. 

Sound familiar?

WhatCable to the rescue

I tried WhatCable on my MacBook Pro and was immediately hooked. While it’s not specifically designed for photographers or content creators, it solves a very real problem for anyone who manages lots of SSDs and card readers: ensuring the cables you use deliver maximum performance. Because if they don’t, you’re going to spend a lot more time waiting around while files transfer.

When you plug a USB device into your Mac, WhatCable will tell you everything you need to know about the cable: the generation of USB the cable supports, the speed the connected device is running at, its power delivery capabilities, and, if available, details like the manufacturer and whether it has an e-marker chip (more on that in a bit).

To my surprise, the cable I’d grabbed for my SSD not only supported its native USB 3.2 Gen 2 (10 Gbps) speed, but was actually a USB4 cable capable of up to 40 Gbps. I’d ordered some of these faster cables, thinking they’d be future-proof for a while, but since there’s no visual way to tell them apart from my older ones, I’d had no idea which was which.

Analyzing the cable connecting my MacBook Pro to my Dell display is even more revealing, and gives a sense of how much detail WhatCable can report, including specifics about the built-in USB hub. You can see the details in the screenshot below.

Elsewhere, the results ran the other way. When I plugged in a Samsung T7 SSD with yet another USB-C cable – short, and similar to the ones that ship in the box with many portable drives – WhatCable informed me that it could only manage USB 2.0 speeds. My guess is that it’s actually a charging cable that came with some other device.

WhatCable also includes widgets for the macOS desktop, letting you see at a glance what speed all your connected devices are running at; clicking one takes you straight to that device’s report in the app. You can also park WhatCable in the menu bar for one-click access to all your USB info.

Suspicious cables

USB cables include an e-marker, a microchip embedded in the connector that acts as a kind of ID card and safety controller. It reports information such as how much power the cable can deliver, its data transfer rates, and its video capabilities, which helps your computer negotiate speed and power at levels that are safe for the connected device.

WhatCable checks whether a cable’s e-marker claims are consistent with USB-IF certification data and flags cables whose reported specs look implausible. The company’s product page describes this trust-checking feature in detail, noting that it can help surface mislabeled or counterfeit cables – a real concern when buying inexpensive cables online.

System requirements and download

WhatCable requires a Mac with Apple Silicon (M1 or later) and running MacOS Sonoma or later. The free version is open source under the MIT license, promises no ads or tracking, and doesn’t report any analytics or telemetry back to the developer. It’s also available in 19 languages, making it broadly accessible. It can be downloaded directly from the developer.

For real nerds, there’s WhatCable Pro, which adds features like the ability to name individual cables and track their performance history, live power metering, display diagnostics, Thunderbolt link analysis, and more. It’s a one-time purchase of £9.99 (about $14) and covers up to two Macs.

So next time you find yourself staring into that abyss, not knowing which cable to grab, you know what to do. One warning: WhatCable is addictive. I found myself testing every USB-C cable in the house, and most of the DPReview staff succumbed to the same temptation after I shared it in our Slack channel. You’ve been warned.

WhatCable Pro — USB-C cable diagnostic app by Bitmoor

• $14 at WhatCable

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The rumor mill around Apple’s upcoming iPhones, set to be announced September 9, has been in full swing for months, and the word on the street is that there’s supposedly one big change coming to the new phone’s cameras: the iPhone 18 Pro Max will get a variable aperture on its main camera. While people have been making this prediction for years, Bloomberg‘s Mark Gurman, who has a pretty decent track record, recently threw his weight behind it.

As an iPhone nerd, there are a lot of things that interest me about this. The first is that it marks a return of Apple differentiating the camera on its biggest, most expensive* model. The Pro Max phones have historically received new camera updates first – the 15 Pro Max got the 5x telephoto camera a year before it came to the standard Pro – but we’ve been in a stretch where the cameras on the Pro models have been exactly the same. If this rumor is true, that’s about to change.

But as a photographer and camera reviewer, I’m skeptical whether this change will matter much. Before we get to the reasons why, let’s talk about the theoretical benefits. At a high level, changing your lens’s aperture lets you control how much light is hitting the sensor and your depth of field (i.e., how blurry the background of your photo is). The smaller the aperture (or, counter-intuitively, the higher your F-number), the less light it lets in, and the more of your image will be in focus. Phones, historically, have quite fast lenses; the iPhone 17 Pro’s main camera shoots at a fixed F1.78. 

In bright, sunny conditions, this means the phone has to cope with a lot of light hitting the sensor, resorting to tricks like using extremely low ISOs and very fast shutter speeds. And as phone companies push to make their lenses faster to improve image quality and flexibility in low light, this becomes even harder. Adding an aperture that can stop down to, say, F4, would help take some of that pressure off.

Mitchell Clark

It’s worth noting that this would almost certainly be the direction Apple goes in, rather than making one that could open up from F1.78 to, say, F1.2. If it was able to make the lens faster, it already would’ve done so. And for phone photographers, that reduces the potential practical benefits; I’ve personally never run into a situation where it was physically too bright for my phone to cope, so an aperture that can stop down isn’t fixing a problem I currently have (with the one exception of video, where the closer you can get to a shutter speed that’s double your frame rate, the more natural motion will look).

The same is true for the other half of the equation, depth of field. To understand why, we have to introduce the concept of equivalent apertures. A F number is absolute; an F1.8 lens on a phone will transmit the same amount of light per square millimeter of sensor as a full-frame F1.8 will. However, because iPhones use much smaller sensors than traditional cameras, the amount of light gathered over the whole image area and the depth of field won’t be equivalent to what you’d get on a full-frame camera with an F1.8 lens. 

Mitchell Clark

The current iPhone 17 Pro main camera has a Type 1/1.28 (71.5mm²) sensor. That means that its F1.78 lens will produce the same depth of field as an F6.1 lens on a full-frame camera. If Apple makes it stop down to, say F4, that would give you a lens with two settings: F6.1 and F13.7 equiv. That’ll definitely make a difference in your available depth of field, but it’ll be a change from “enough” to “more than enough,” rather than making a huge difference to the types of shots you can get in most cases. It also, importantly, won’t make any difference if you want to get the coveted shallow depth of field look that the iPhone currently has to emulate with portrait mode.

Finally, let’s consider some historical context. Back when compact cameras were dominant, many of them used sensors that were similar sizes to the iPhone, and had the ability to change apertures. But while some had actual aperture blades like a traditional lens, others used a Waterhouse stop, moving a plate with a fixed aperture in between the lens and the sensor to stop down when needed.

This is less flexible – you don’t get the stops in between wide open and the plate’s diaphragm – but is mechanically simpler. That’s likely a huge consideration for Apple when it comes to building a device that will be subjected to pretty much every condition and abuse you can think of. This is, after all, a company that replaced a physical home button with a solid state one (and is rumored to have at least considered doing the same for the rest of the phone’s buttons, too).

DPReview

Some compacts also simply slotted in an ND filter, and reported it as a stopped down aperture, since it had the same effect on the incoming light. (It didn’t affect the depth of field, but, again, they already had plenty). Apple could go either of those routes rather than building a standard aperture, and it would have good reason to; going the traditional way may have reliability concerns, and could cost more at a time when Apple’s also being squeezed when it comes to chip pricing and availability.

With that said, we’ve seen phones with physical aperture mechanisms before. Samsung included the feature on the Galaxy S9 and S10, to extremely middling results. You essentially couldn’t tell the difference, and the company ended up dropping the feature. Huawei has several phones in its lineup today with variable apertures, but it essentially never gets a mention on the feature pages, despite how much of them are dedicated to talking about the cameras.

However Apple decides to implement it, if it does at all, the point is the same: it’s unlikely to be something you actually notice when it comes to the experience of using your phone as a camera or the photos you get out of it. But that’s not to say that Apple has just decided to make one of the most mechanically complex parts of its phones even more complicated for giggles, or that it’ll purely be a marketing gimmick.

To the latter point, I’m honestly 50/50 on whether I think it’ll bring it up in the keynote presentation at all (again, assuming the rumors are even accurate). There’s probably some technical reason why it’ll be nice to have as part of its computational image processing pipeline, and there may even be a slight noticeable benefit to it. And if, by some miracle, Apple has decided to massively increase the size of the camera sensor, then it could genuinely be an important inclusion, though, to be clear, that change hasn’t been rumored at all.

But don’t get your hopes up. At the end of the day, the odds are that iPhone photos will still look like iPhone photos (which is to say: pretty good, for a phone), and that there won’t be an appreciable difference between the camera on the iPhone 18 Pro and the one on the 18 Pro Max… or, for that matter, between the new phone and the one it’s replacing. Sometimes, a change is just a change, no matter how much buzz there is about it leading up to it.

* – Currently most expensive, anyways. Apple is also expected to introduce a folding phone that will almost certainly be priced above the Pro models and that will have worse cameras, if other major foldables are any indication.