Reasons to choose Alpha a7R III
Released in 2017, Alpha a7R III has about 862 mm² of sensor area, 42.4 MP effective resolution, and a 657 g body. Use these values to narrow the field, not as an overall image-quality score.
Side-by-side comparison
Sony Alpha a7R III
vs Sony Alpha a9
VS
Sensor area
862 mm²
Alpha a7R III847 mm²
Alpha a9- Area ratio
- 1.02:1
- Absolute difference
- 14 mm²
- Relative difference
- 1.7%
The Alpha a7R III has the larger sensor area. More area usually means greater light-gathering potential, though real image quality still depends on sensor architecture and generation.
Key specification differences
Alpha a7R IIIMetricAlpha a9
42.4 MPEffective pixels24.2 MP
35.9 × 24Sensor35.6 × 23.8
4.51 µmPixel pitch5.92 µm
20.32 µm²Pixel area35.01 µm²
4.92 MP/cm²Pixel density2.86 MP/cm²
1Crop factor1.01
3,840 × 2,160Maximum video3,840 × 2,160
657 gWeight673 g
SD/SDHC/SDXC/MS PRO DuoStorageSD/SDHC/SDXC/MS PRO Duo
NP-FZ100 lithium-ion battery Li-ion batteryBatteryNP-FZ100 lithium-ion battery Li-ion battery
Amber marks the value that is generally preferable in this comparison context. It is not an overall camera score.
How to choose between these cameras
The Alpha a7R III has the larger sensor area. The Alpha a7R III has the lighter body. The Alpha a7R III has the higher effective resolution. The Alpha a7R III and Alpha a9 were both released in 2017. Also consider the lens system and subjects you shoot.
Reasons to choose Alpha a9
Released in 2017, Alpha a9 has about 847 mm² of sensor area, 24.2 MP effective resolution, and a 673 g body. Use these values to narrow the field, not as an overall image-quality score.