The Pentax 645Z features 51.4MP Full Frame Exmor CMOS Sensor and ISO range 100-204800 on the other hand Sony Alpha a7R features 36.4MP Full Frame Exmor CMOS Sensor and ISO range 50-25600, take a look at the Major Specification Below.
Pentax 645Z vs. Sony Alpha 7R Specification Comparison Table.
Megapixel: The Pentax 645Z features more resolution compared to Sony Alpha 7R, so you will get large printouts and you can also re-compose /crop your images after shooting.
Bigger Sensor Size: Pentax 645Z have bit bigger sensor size compared to Sony Alpha 7R, bigger sensors have more light gathering area hence you get better low-light performance, more color depth and increased dynamic range.
Better low light performance – The Pentax 645Z features better low-light range than Sony Alpha 7R, The Pentax 645Z standard ISO range is 100-204800, with the amazing ISO range of Pentax 645Z you get super clean images at low-light situation when compared to its competitor.
Top Continuous shooting speed: Sony Alpha 7R features fast shooting speed (4fps vs. 3fps) compared to Pentax 645Z.
Better Shutter Range: Sony Alpha 7R features better shutter range compared to Pentax 645Z. Fast shutter range will help you to capture amazing action shots.
AF System: Both camera features advance AF system.
Display: Sony Alpha 7R features bigger and high resolution display compared to Pentax 645Z.
Sony Alpha 7R features large tilting Screen display on the other hand Pentax 645Z have fixed display, so we get more flexibility while composing our shot with Sony Alpha 7R.
Wireless: Sony Alpha 7R has a Wi-Fi+NFC; on the other hand Pentax 645Z doesn’t have NFC.
High ISO Test Between Pentax 645Z vs. Sony Alpha 7R
The Pentax 645Z have large Medium format sensor and Sony A7r limited to full frame 35.9 x 24 mm size, at ISO 12800 the 645zand Sony A7R image quality is almost same but you will get bigger size.. so you get large printout or feed the client desired megapixel needs…So if you need more megapixels by investing more money you should buy the Pentax 645Z camera … If you don’t need 50MP resolution and Sony A7R 36MP is sufficient for you than you must go with Sony A7R since you will get Sony A7R + few high quality lenses at the price of 645Z.