Setting shutter speed by hand on the iPhone 18 Pro comes with a trade-off Apple did not mention at launch. The phone stops combining multiple frames into a single photo, and Night mode is no longer available. The result is a noisier image, especially in low light.
DPReview’s testing found that the iPhone 18 Pro appears to capture one frame at your chosen shutter speed instead of its usual burst. Apple’s launch materials focused on the new mechanical variable aperture on the main camera, a first for the iPhone, and on the Pro controls for setting aperture, shutter speed and white balance manually.
Manual shutter speed gives you one frame instead of a stack
Like every smartphone, the iPhone 18 Pro relies on computational photography to make up for a small sensor. It shoots a rapid burst, aligns the frames and merges them into one photo. Averaging those frames reduces noise and improves dynamic range, a process often called frame stacking or frame blending.
Apple introduced Pro controls for manual aperture, shutter speed and white balance with the iPhone 18 Pro, and shutter speed is the one that changes how the photo is processed. Manual aperture leaves frame stacking in place. Manual shutter speed does not. Here is how the four setups DPReview tested compare:
- Full auto stacks multiple frames.
- Manual aperture also stacks multiple frames.
- Manual shutter speed captures a single frame.
- Manual aperture and manual shutter speed together capture a single frame.
The behavior has a defensible logic, since multi-frame capture normally blends frames of different durations, which clashes with choosing your own exposure time. Stacking several frames at your selected shutter speed is possible in principle, but a burst takes longer to capture, and the final image would blend several moments instead of recording one.
Low light photos show the biggest difference
DPReview shot static scenes on a tripod with the main camera, in conditions ranging from bright daylight to night. Each scene was captured all four ways, with aperture and shutter speed matched across the set. Night mode was disabled so it would not skew the comparison.
The widest gap appeared in a dim walkway scene shot at f/1.48, 1/15 sec and ISO 10000. A second night scene at f/1.48 and 1/30 sec was less extreme but still showed a noticeable difference. The auto exposure shot used ISO 640 there, while the manual shutter version used ISO 400.
Bright light narrows the gap considerably in a sunny aspen scene, where the auto exposure shot was taken at f/1.8, 1/2500 sec and ISO 64. The manual shutter version used f/1.7, 1/2000 sec and ISO 50, since auto mode often picks shutter speeds that cannot be selected by hand, and DPReview used the closest available option.
Any setup with a manually selected shutter speed can produce more noise, whether or not the aperture was also set by hand. It is most visible in low light and deep shadows. Manual aperture on its own produced essentially the same results as full auto.
Manual shutter speed makes sense for motion, not for clean night shots
DPReview recommends saving manual shutter speed for creative choices that depend on exposure time, such as motion blur or freezing action, and accepting that you are getting a single frame. If the shot would not have been possible without manual control, the trade-off is probably worth it. Otherwise, auto shutter speed gives a cleaner image, particularly at night.
DPReview does not think Apple got this wrong. A single frame at the shutter speed you picked is also what a dedicated camera gives you. Third-party camera apps are adding their own exposure modes too, including aperture priority in Halide 3.2.
Pro controls do not include an ISO setting, so the iPhone 18 Pro still picks ISO automatically even when shutter speed is set manually.
