The iPhone 18 Pro is not expected to be a significant upgrade over the iPhone 17 Pro, with arguments suggesting buyers consider the current model ahead of next week's launch. The most notable anticipated feature is a variable aperture lens for the primary camera, a first for the iPhone lineup. This would allow users to control depth of field, mimicking DSLR capabilities by adjusting aperture width for shallow background blur in portraits or deep focus in landscapes.

However, the practical impact may be limited. The primary constraint on iPhone depth of field is the tiny sensor size compared to dedicated cameras, which will not change this year. Physics dictates that a slightly wider aperture on the same small sensor yields only marginal improvements. Including a mechanically variable aperture is complex and expensive, raising questions about Apple's motivation if the optical benefit is minimal.

This suggests Apple may have additional computational photography enhancements planned to leverage the new hardware. The variable aperture could serve as cover for significant software-driven image processing improvements that deliver results beyond what the optics alone would allow. Whether this feature arrives on both Pro models or solely the Pro Max remains unclear.