The iPhone 18 Pro's main camera features a variable aperture, which allows users to adjust the lens opening to control how much light enters and how much of the background is blurred in photos. However, when using Apple's native iOS camera app, users are limited to just four manual settings: f/1.48, f/1.8, f/2.8, and f/4. This limitation also applies when the camera app automatically adjusts the aperture. While this might seem like a hardware restriction, Apple's software development kit (SDK) actually allows third-party camera apps to offer more detailed control over the aperture settings. Third-party apps like Blackmagic Design's BlackMagic Camera for iOS have taken advantage of this flexibility. The app, which is free and well-regarded for its features, was among the first to support the iPhone 18 Pro’s adjustable aperture. Instead of just four settings, it offers 10 presets with additional options in between, giving users finer control over the aperture. Recently, the iPhoneographers YouTube channel tested version 3.5 of the app and described it as "pretty buggy," but an updated version, 3.5.1, has since been released with improved performance and stability. Another app, Moment Pro Camera II, has also been updated to support the iPhone 18 Pro's variable aperture. Priced at $12.99, this app allows users to adjust the aperture from f/1.48 to f/4.0 in 1/3 stop increments, similar to Blackmagic's offering. This approach mirrors how most digital cameras function, giving users more control over depth of field and background blur. However, due to the iPhone 18 Pro’s relatively small camera sensor, the differences in background blur between each 1/3 stop adjustment may be subtle and hard to notice in practice. Despite this, having more control over camera settings is generally seen as a positive, even if the differences are small. It allows for greater creative flexibility and can be especially useful for photographers who want to fine-tune their shots. As more third-party apps continue to support the iPhone 18 Pro’s advanced camera features, users may find themselves with more options for capturing high-quality images.