Here is a quick comparison video of Canon EOS 5Ds, Nikon D810, Pentax 645z, Sony a6000 and Olympus EM5 II shutter sounds.
As a result we can say the Olympus OM-D E-M5 II can shoot 1/16000 with a silent shutter mode using an electronic shutter, and it’s absolutely silent.
Shutter sounds – Canon 5Ds. Nikon D810, Pentax 645z, Sony a6000 and Olympus OMD Em5 II
The OM-D E-M5 Mark II ($1,099 – Amazon | Adorama) mirrorless camera boasts an electronic shutter with a top shutter speed of 1/16,000 sec, plus a new AF Targeting Pad function that works similarly to Panasonic’s venerable Touch Pad AF.
50MP Canon EOS 5Ds and 5DS R ($3,399 – Amazon | Adorama) DSLR cameras features dual DIGIC 6 processors, a 61-point AF system with 41 cross-type points and a 150,000-pixel RGB+IR metering sensor with 252 zones. The EOS 5DS and 5DS R are capable of 1080/30p HD video recording and offer dual SD/CF card slots.
Nikon D810 ($2,796 – Amazon | Adorama) features a brand new 36.3 megapixel sensor with no optical low pass filter, Expeed 4 image processing engine, 51-point auto-focus system and 5fps burst shooting at full resolution.