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Main
Model
Price
Advantages
SENSOR Effective pixels: 24 megapixels
SENSOR Max resolution: 6000 x 4000
SENSOR Sensor size: Full frame (35.6 x 23.8 mm)
SENSOR Sensor photo detectors: 28 megapixels
IMAGE Boosted ISO (maximum): 204800
PHOTOGRAPHY FEATURES Continuous drive: 20.0 fps
SCREEN / VIEWFINDER Screen dots: 1,440,000
OPTICS & FOCUS Number of focus points: 693
Main
Model
Price
Advantages
PHOTOGRAPHY FEATURES Subject / scene modes: Yes
PHOTOGRAPHY FEATURES Built-in flash: Yes (Pop-up)
SCREEN / VIEWFINDER Screen size: 3.2″
SCREEN / VIEWFINDER Viewfinder type: Optical (pentaprism)
PHYSICAL Weight (inc. batteries): 640 g (1.41 lb / 22.58 oz)
PHYSICAL Battery Life (CIPA): 950
OTHER FEATURES GPS: Optional
Summary
The Alpha a9 highest resolution of 6000 x 4000 pixels (24 megapixels) is better in comparison with the D7500 maximum resolution of 5568 x 3712 pixels (21 megapixels). The Alpha a9 is produced with larger sensor than the D7500: Full frame (35.6 x 23.8 mm) versus APS-C (23.5 x 15.7 mm). It is the most important advantage of this camera as big sensor allows the photographer to shoot pictures of the higher quality. The Alpha a9 provides more focus points in compare with the D7500: 693 vs 51. More number of focus points means less risk of losing focus lock when tracking a moving object.
The Alpha a9 display is better as it has more screen dots 1,440,000 in comparison to 922,000 dots of the D7500 display. The higher dot count display is better for reviewing photos on your camera.
The D7500 is equipped with built-in flash. The D7500 battery life is better than the Alpha a9 battery life. According to CIPA standards the camera owner will be able to produce 950 photos with the D7500 and only 650 with the Alpha a9. The Nikon D7500 weighs 640g that is 33g less in comparison with the weight of the Alpha a9. The Nikon D7500 can utilize optional accessory GPS devices. This feature can be convenient for the travel photographer, to be able to check the image metadata and see exactly where a photo was shot.
Considering the above differences the Alpha a9 becomes the best buy. Check the lowest price on Amazon