Update – May 16, 2026: Possible improvement on iOS 26.5
After updating to iOS 26.5, I retested the iPhone 17 (non-Pro) under my own shooting conditions and did not observe the same severe star-focus failures described in this article.
iPhone 17 (iOS26.5)
This does not yet prove that iOS 26.5 has fully fixed the issue for all iPhone 17 units. More testing under comparable conditions is still needed, and I have not yet seen broad international reports confirming the same improvement.
However, based on this retest, I now believe my earlier statement that this issue might be difficult to fix through software updates alone was too strong. The original iOS 26.2 test results remain valid as a record of what I observed at the time, but my interpretation of the long-term fixability of the issue should be revised.
・I tested seven iPhones under the same dark sky: 5× iPhone 17, 1× iPhone 17 Pro, 1× iPhone 16 – all on iOS 26.2.
・In this test, iPhone 17 Pro and iPhone 16 did not miss focus even once on the stars.
・All five iPhone 17 (non-Pro) units showed unstable focus: only about 9–20% of the shots were “perfectly focused” on stars, even on a tripod.
・At the time of testing on iOS 26.2, the results suggested that the issue was not limited to a single “bad unit,” but was likely related to how the iPhone 17 (non-Pro) handled star-like point-light sources under those conditions.
・After a later retest on iOS 26.5, the same severe focus failures were no longer observed in my environment. Therefore, this article should be read primarily as a record of the iOS 26.2 behavior, not as a final conclusion about the current state of iPhone 17.
1. What a “good” iPhone 17 frame can look like
iPhone 17 (non-Pro) — one of the rare well-focused frames
At first glance, this looks like a clean shot. However, with the iPhone 17 (non-Pro), getting even this one sharp frame required multiple attempts.
Most other frames from the same session were noticeably out of focus on the stars.
This article focuses on focus reliability — how often stars actually come out sharp — across five different units.
2. The core issue: focus that randomly misses, even on a tripod
[Shot on iPhone 17]
The two frames above were shot with:
・The same iPhone 17 unit
・On a tripod
・With identical settings
・only seconds apart
Even under these conditions, one frame can be in focus while the next frame is clearly out of focus on the stars. This is the behavior discussed in many online user reports. A key question is whether this is unit-to-unit variation or a more general tendency.
3. Test setup: 5× iPhone 17 + 17 Pro + 16 (7 units total)
Devices
For this test, I prepared five brand-new retail iPhone 17 (non-Pro) units. All were Black, and I intentionally mixed storage options and purchase timing.
・iPhone 17 A – 256 GB, bought on Amazon Japan (Dec 2025)
・iPhone 17 B – 256 GB, bought from Apple Online Store (Dec 2025)
・iPhone 17 C – 512 GB, bought from Apple Online Store (Dec 2025)
・iPhone 17 D – 512 GB, bought from Apple Online Store (Dec 2025)
・iPhone 17 E – 256 GB, bought from Apple Online Store at launch (Sep 2025, early batch)
To have a reference:
・iPhone 17 Pro – 1 unit
・iPhone 16 (non-Pro) – 1 unit
All devices ran iOS 26.2.
Shooting conditions
・Location: a dark rural mountain area in Shikoku, Japan
・All phones mounted on tripods.
・Pointed in almost the same direction toward a dark star field.
(no specific constellation – the goal was simply “do the stars come into focus or not?”)
・ I repeatedly pressed the shutter on each device and then classified every frame.
Classification (how each frame was judged)
Each frame was classified into one of three categories:
・Match – Stars are sharp and well-defined, with no noticeable softness or smearing.
・Acceptable – Slightly soft, but usable in practice on a phone screen
・Out of focus – Stars are clearly smeared/blurred; the shot is a miss for astrophotography
For step-by-step instructions (Night mode settings, exposure tips, etc.), see this guide: → iPhone Astrophotography(iOS 26): No Tripod Needed
4. Results: numbers, not just impressions
Per-device results (number of frames)
| Device | Match | Acceptable | Out of focus | Total |
| iPhone 16 | 78 | 0 | 0 | 78 |
| iPhone 17 Pro | 79 | 0 | 0 | 79 |
| iPhone 17 A | 13 | 11 | 57 | 81 |
| iPhone 17 B | 15 | 11 | 48 | 74 |
| iPhone 17 C | 13 | 12 | 53 | 78 |
| iPhone 17 D | 11 | 7 | 62 | 80 |
| iPhone 17 E | 7 | 3 | 67 | 77 |
The slight differences in total shots come from throwing out obvious human errors (accidental shake, mis-tap, etc.) that aren’t related to autofocus behavior.
Here is an example frame from the test:
In this example, I classified each phone as follows:
◎ (perfect focus): iPhone 16, iPhone 17 Pro
△ (acceptable): iPhone 17 B
× (out of focus): the remaining iPhone 17 units
Even within the × group, the blur doesn’t look the same on every device.
Some units only produce slightly swollen stars, while others break the star shapes down much more aggressively. In this sample, the iPhone 17 E shows the most obvious breakdown of the star images.
What this means in plain language
・iPhone 16 and iPhone 17 Pro
→ In this series, they never missed focus on the stars (78/78 and 79/79).
・iPhone 17 (non-Pro)
→ “Match” shots (perfectly focused) were only about 9–20% per unit.
Even if you include “Acceptable” frames, a large share of images on every unit are clearly out of focus and unusable for serious astrophotography.
In other words, this is not about “one bad unit.” All five iPhone 17 units showed poor and inconsistent focus reliability on stars.
5. This doesn’t look like a one-off defect
If this were just a manufacturing defect, you would normally expect at least one “good” unit out of five. Instead, every iPhone 17 (A–E) behaved in the same general way:
・Stars are much more likely to be soft or smeared than crisply focused
・The “perfect hit” shots are the minority, even on a tripod
Given that:
・All devices ran the same iOS version (26.2)
・iPhone 17 Pro and iPhone 16 never missed focus under the same conditions
・Five different iPhone 17 units all showed the issue to varying degrees
…it’s hard to blame this on:
・Environment
・OS version
・A single unlucky unit
The more reasonable interpretation is:
At the time of this iOS 26.2 test, the results did not look like a single unlucky unit. A more reasonable interpretation was that the iPhone 17 (non-Pro) had a weakness in its camera tuning or autofocus behavior when dealing with tiny point-light sources such as stars.
However, a later retest on iOS 26.5 did not reproduce the same severe focus failures in my environment. For that reason, I would now avoid calling this a fixed structural limitation. It may have been a software-tuning issue, or at least a behavior that software updates can improve.
6. Early-batch behavior felt noticeably worse in the field
One unit deserves a special mention: iPhone 17 E, bought at launch (early batch).
During the tests, I checked each frame on the preview screen as I went.
My subjective impression was:
・Later units (A–D, bought in December)
→ Mixed results: some completely missed shots, but also “almost there” and a few really good ones
・Early-batch unit (E)
→ Frame after frame of star fields that looked hopelessly blurred
The numbers support that impression:
・iPhone 17 E managed only 7 “Match” shots out of 77 (about 9%).
But honestly, the feeling while shooting was worse than the percentage suggests:
・The AF behavior itself felt unreliable
・It often seemed to never really “lock” onto the stars at all
・It just kept producing soft, bloated star images
To be clear: this is still a sample of one early-batch device.
We can’t claim “all early 17s are broken.” But within this small group of five, the launch unit clearly behaved like the worst of the bunch.
7. Can software updates fix this? My view has changed after iOS 26.5
When I originally wrote this article, I had tested the early-batch iPhone 17 across multiple iOS updates since launch and had not seen meaningful improvement in star-focus behavior.
Because of that, I speculated that existing devices — especially early-batch units — might not be fully fixable by software updates alone.
After retesting on iOS 26.5, I now think that statement was too strong. In my own shooting environment, the severe focus failures described in this article were no longer observed after the update.
This does not prove that iOS 26.5 has completely fixed the issue for every iPhone 17 unit. The test conditions were not perfectly identical, and more repeat testing is needed. However, the iOS 26.5 result is enough for me to revise my earlier interpretation: software improvement appears more plausible than I originally believed.
8. Conclusion: iOS 26.2 showed a serious focus issue, but iOS 26.5 requires a revised view
In this multi-unit test on iOS 26.2:
・iPhone 16 and iPhone 17 Pro showed stable star focus, with no misses in this series.
・All five iPhone 17 (non-Pro) units showed low and inconsistent focus reliability on stars.
Those results remain important. They show that, under my iOS 26.2 test conditions, the iPhone 17 (non-Pro) had a serious and repeatable star-focus problem across multiple units.
However, after updating to iOS 26.5 and retesting, I did not observe the same severe focus failures in my environment. Because of this, I no longer think it is appropriate to describe the issue as a confirmed structural limitation or to say that software updates are unlikely to help.
At this point, the most accurate conclusion is more cautious: iOS 26.2 showed a serious star-focus reliability problem on the iPhone 17 (non-Pro), while iOS 26.5 may have improved the behavior. Further testing is needed before calling it a complete fix.
I apologize if my earlier wording gave readers the impression that the issue could not be improved by software. Based on the iOS 26.5 retest, I now think that conclusion was too strong.
