Olympus E-M1 III vs Pentax 645Z

Here is a in-depth comparison of the Olympus E-M1 III vs Pentax 645Z, former being a Pro Mirrorless while the latter is a Pro DSLR by rivals Olympus and Pentax. There exists a substantial gap between the sensor resolutions of the E-M1 III (20MP) and 645Z (51MP) and the E-M1 III (Four Thirds) and 645Z (Medium format) come with totally different sensor dimensions.

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The E-M1 III was brought out 5 years later than the 645Z and that is quite a big difference as far as technology is concerned. Both of the cameras come with different body type with the Olympus E-M1 III being a SLR-style mirrorless camera and the Pentax 645Z being a Large SLR camera.

Before delving straight into a more detailed comparison, below is a simple summary of how the E-M1 III matches up versus the 645Z in terms of portability, imaging, features and an overall rating.

The following is a preview of the gallery images for Olympus OM-D E-M1 Mark III & Pentax 645Z. The entire galleries are provided at Olympus E-M1 III Gallery & Pentax 645Z Gallery.

If you are intending to carry your camera often, you have to consider its weight and dimensions. The Olympus E-M1 III enjoys outer dimensions of 134mm x 91mm x 69mm (5.3" x 3.6" x 2.7") with a weight of 580 grams (1.28 lbs) and the Pentax 645Z has dimensions of 156mm x 117mm x 123mm (6.1" x 4.6" x 4.8") having a weight of 1550 grams (3.42 lbs).

Contrast the Olympus E-M1 III vs Pentax 645Z in our brand new Camera & Lens Size Comparison Tool.

Remember that, the weight of an ILC will change dependant on the lens you have attached at that time. Here is the front view overall size comparison of the E-M1 III versus the 645Z.

Considering dimensions and weight, the portability grade of the E-M1 III and 645Z is 67 and 49 respectively.

Sometimes, it's hard to see the contrast between sensor sizing only by checking a spec sheet. The visual here should give you a better sense of the sensor dimensions in the E-M1 III and 645Z.

Clearly, both of those cameras have got different resolutions and different sensor sizing. The E-M1 III because of its tinier sensor will make achieving shallow DOF more challenging and the Pentax 645Z will resolve greater detail having its extra 31MP. Higher resolution can also allow you to crop photographs much more aggressively. The younger E-M1 III is going to have an advantage in sensor innovation.