Reasons to choose EOS 5D Mark III
Released in 2012, EOS 5D Mark III has about 864 mm² of sensor area, 22.3 MP effective resolution, and a 950 g body. Use these values to narrow the field, not as an overall image-quality score.
Side-by-side comparison
Canon EOS 5D Mark III
vs Pentax 645D
VS
Sensor area
864 mm²
EOS 5D Mark III1,452 mm²
645D- Area ratio
- 1.68:1
- Absolute difference
- 588 mm²
- Relative difference
- 68.1%
The 645D has the larger sensor area. More area usually means greater light-gathering potential, though real image quality still depends on sensor architecture and generation.
These cameras were released 2 years apart. Consider sensor generation when comparing pixel metrics.
Key specification differences
EOS 5D Mark IIIMetric645D
22.3 MPEffective pixels40 MP
36 × 24Sensor44 × 33
6.22 µmPixel pitch6.02 µm
38.74 µm²Pixel area36.3 µm²
2.58 MP/cm²Pixel density2.75 MP/cm²
1Crop factor0.79
1,920 × 1,080Maximum video—
950 gWeight1,400 g
Compact Flash Type I (UDMA compatible), SD/SDHC/SDXCStorageSDHC, Secure Digital
Lithium-Ion LP-E6 rechargeable battery Li-ion batteryBatteryLithium-Ion D-LI90 rechargeable 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 645D has the larger sensor area. The EOS 5D Mark III has the lighter body. The 645D has the higher effective resolution. The EOS 5D Mark III is the newer release. Also consider the lens system and subjects you shoot.
Reasons to choose 645D
Released in 2010, 645D has about 1,452 mm² of sensor area, 40 MP effective resolution, and a 1,400 g body. Use these values to narrow the field, not as an overall image-quality score.