iPhone 17 Pro main camera crop factor: 3.46×
Apple describes the iPhone 17 Pro main camera as "24 mm, ƒ/1.78". Both numbers are full-frame equivalents of a lens that is really about 6.8 mm long in front of a sensor roughly 3.5× smaller than full frame. Its ≈ 10.0 × 7.5 mm sensor has a 12.50 mm diagonal: a crop factor of 3.46×.
A 6.765 mm lens on a phone sensor (3.52× crop) frames like a 24 mm lens on full frame. At f/1.8 it gives the depth of field of about f/6.3 there — but exposure stays the same as f/1.8.
- Horizontal field of view
- 71.8°
- Vertical field of view
- 57.4°
- Crop ratio
- 3.52×
- Sensor size
- 9.8 × 7.4 mm
Full-frame equivalent of a 6.765 mm f/1.8 lens on each format
| Sensor | Focal length | Aperture (DoF) |
|---|---|---|
| Full frame | 7 mm | f/1.8 |
| APS-C (1.5×) | 10 mm | f/2.8 |
| Canon APS-C (1.6×) | 11 mm | f/2.9 |
| Micro Four Thirds | 14 mm | f/3.6 |
| 1-inch | 18 mm | f/4.9 |
| Medium format (44×33) | 5 mm | f/1.4 |
| Phone main camera (1/1.3″) | 24 mm | f/6.3 |
Sensor size and crop factor
Crop factor is the full-frame diagonal (43.27 mm) divided by the sensor diagonal. For the iPhone 17 Pro: √(10² + 7.5²) = 12.50 mm, and 43.27 ÷ 12.50 = 3.46. The calculator uses the generic Phone main camera (1/1.3″) format (3.52×); the tables below use the iPhone 17 Pro main camera’s own sensor size (3.46×), so equivalents differ by 2%.
| Property | Value |
|---|---|
| Sensor size | ≈ 10.0 × 7.5 mm |
| Diagonal | 12.50 mm |
| Crop factor (computed) | 3.46× |
| Crop factor quoted by the maker | Not published (Apple quotes 24 mm equivalent) |
| Area vs full frame | 9% |
| Circle of confusion (diagonal ÷ 1443) | 0.009 mm |
| Resolution / pixel pitch | 48 MP · 1.25 µm |
| Lens mount | fixed lens |
Source: Apple specifications: 48MP Fusion Main camera, 24 mm, ƒ/1.78 aperture. Apple does not publish sensor dimensions; the 1/1.28-inch optical format reported by reviewers (about 10.0 × 7.5 mm, 12.5 mm diagonal) is used here. iPhone 16 Pro photos record a real focal length of 6.765 mm for the same 24 mm ƒ/1.78 main camera.
Main camera focal length settings
The full-frame equivalent is the focal length × 3.46. The DoF-equivalent aperture (f-number × 3.46) describes depth of field and total light at the same framing; exposure — shutter speed and ISO — is set by the real f-number as usual. The 28, 35 and 48 mm settings crop the sensor, which multiplies the effective crop factor.
| Camera setting | Real focal length | Effective crop | Computed equivalent | DoF-equivalent aperture | Horizontal view | Hyperfocal distance |
|---|---|---|---|---|---|---|
| 24 mm 1× (default) | 6.765 mm | 3.46× | 23.4 mm | f/6.2 | 72.9° | 2.86 m9.39 ft |
| 28 mm 1× option | 6.765 mm | 4.04× | 27.3 mm | f/7.2 | 64.7° | 3.34 m11.0 ft |
| 35 mm 1× option | 6.765 mm | 5.05× | 34.1 mm | f/9.0 | 53.8° | 4.17 m13.7 ft |
| 48 mm 2× crop | 6.765 mm | 6.92× | 46.8 mm | f/12.3 | 40.6° | 5.72 m18.8 ft |
What is different about the iPhone 17 Pro
Phone makers quote focal lengths as full-frame equivalents because the real numbers mean little to most people. The iPhone’s main lens records a real focal length of about 6.8 mm in its photo metadata; multiplied by a crop factor of about 3.46×, that gives a 23–24 mm field of view, which Apple rounds to 24 mm. Apple does not publish exact sensor dimensions, and "1/1.28-inch" is a nominal optical format, so the computed equivalent can differ from Apple’s figure by a few percent.
The f/1.78 aperture is real — it sets exposure exactly as on any camera — but its depth of field is that of about f/6.2 on full frame. That is why the main camera keeps everything from a few metres to the horizon sharp, and why Portrait mode blur is computed from a depth map rather than produced optically. The 28, 35 and 48 mm settings are crops of the same sensor: they change the framing and reduce the resolution and the effective sensor size, so their depth of field matches an even smaller aperture.
FAQ
What is the crop factor of the iPhone 17 Pro main camera?
About 3.46×. Apple does not publish sensor dimensions; the reported 1/1.28-inch format is about 10.0 × 7.5 mm with a 12.5 mm diagonal, and 43.27 ÷ 12.5 = 3.46.
What is the real focal length of the iPhone 17 Pro main camera?
About 6.765 mm, as recorded in the photo metadata. Multiplied by the 3.46× crop factor that frames like a 23.4 mm lens on full frame, which Apple quotes as 24 mm.
What is the equivalent aperture of the iPhone 17 Pro main camera?
f/1.78 for exposure, but about f/6.2 for depth of field and total light compared with full frame. Its hyperfocal distance is only 2.86 m (9.39 ft), so focusing a few metres away keeps everything to infinity acceptably sharp.
Is the iPhone 17 Pro’s 2× (48 mm) an optical zoom?
No. Apple calls it "optical quality" because it crops the central 12 MP of the 48 MP sensor rather than upscaling. The lens stays the same 6.8 mm, so at 48 mm equivalent the camera behaves like a sensor about 6.9× smaller than full frame, with the depth of field of about f/12 on full frame.
Other cameras
- Sony a640023.5 × 15.6 mm · 1.53× crop
- Sony a670023.3 × 15.5 mm · 1.55× crop
- Sony ZV-E1023.5 × 15.6 mm · 1.53× crop
- Canon EOS R5022.3 × 14.9 mm · 1.61× crop
- Canon EOS R1022.3 × 14.9 mm · 1.61× crop
- Nikon Z5023.5 × 15.7 mm · 1.53× crop
- Fujifilm X-T523.5 × 15.6 mm · 1.53× crop
- Panasonic Lumix G9 II17.3 × 13 mm · 2.00× crop
- Sony RX100 series13.2 × 8.8 mm · 2.73× crop
More on the Phone main camera format — depth of field, hyperfocal and star charts — on the Phone main camera (1/1.3″) sensor page. The theory is in crop factor explained.