Sony A7R III has a 42.0MP Full frame (35.9 x 24 mm ) sized BSI-CMOS sensor and features Bionz X processor. You can shoot at maximum resolution of 7952 x 5304 pixels with aspect ratios of 3:2 and 16:9. A7R III has a native ISO range of 100 - 32000 which can be boosted to 50 - 102400 and it can save files in RAW format which gives you a wider room for post processing.
Sony A7R III is not the highest resolution Full frame camera. Blackmagic PYXIS 12K with its 98.8MP sensor is leading in this class. Check the comparison of Sony A7R III vs Blackmagic PYXIS 12K or take a look at Highest resolution Mirrorless cameras list.
Sony A7R III DxOMark Sensor Scores
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. Sony A7R III sensor has been tested by DxO Mark and got an overall score of 100 for its image quality. You can find the details of their analysis of Sony A7R III here.
High Resolution Mode
Sony A7R III has a special High Resolution mode where the camera takes multiple images of a scene while moving its sensor using the sensor shift image stabilization system and combine them automatically to create a 169 MP MP image. This feature works best with static scenes and using a tripod is a must to minimize stitching artifacts.
Anti-Aliasing Filter
Another important feature about Sony A7R III's sensor is the lack of anti-alias (Low-pass) filter. Removing anti-aliasing filter increases the sharpness and level of detail but on the other side it also increases the chance of moiré occurring in certain scenes.
Let's look at how the size of the Sony A7R III's Full frame sensor compares with other standard sensor sizes.
Comparison image of Sony A7R III Sensor Size with other standard sensors
Sensor size is what determines the circle of confusion, and therefore how much
depth of field Sony A7R III gives you at any given aperture.
You can
calculate
the exact depth of field for the Sony A7R III
at any focal length, aperture and subject distance, including the hyperfocal distance
for landscapes and the very shallow focus zone you get with long telephoto lenses.
