fetzler wrote:
I have this Oly lens too. I use it to photograph my pet parrot. He is a tough subject as he likes the camera and tries to look in the lens or jump on my hands. The lens is also good for landscape use and making panoramas.
While the 45mm Olympus lens has an effective field of view similar to 90mm on full frame, and provides the EXPOSURE of f/1.8, it has similar depth of field as f/3.5 would on full frame.
At 8 feet, f/1.8, 45mm on Olympus OM-D E-M1 Mark III, DOF = 0.50 feet (7.76 ft to 8.26 ft)
At 8 feet, f/3.5, 90mm on Canon 5D Mark IV, DOF = 0.51 feet (7.75 ft to 8.26 ft) (assuming you can find a Canon EF mount 90mm f/1.8 lens...)
At 8 feet, f/3.5, 85mm on Canon 5D Mark IV, DOF = 0.57 feet (7.73 ft to 8.29 ft)
At 8 feet, f/1.8, 42.5mm on Canon 5D Mark IV, DOF = 0.56 feet (7.73 ft to 8.29 ft)
Source: DoFC app for iPhone, iPad, and Apple Silicon Macs
So when comparing full frame with Micro 4/3, for equivalencies, use half the focal length as you would on full frame and assume two stops more depth of field on Micro 4/3 at the same aperture. To keep DOF the same, you need faster lenses on m43.
(One of my favorite things about m43 is that there is more depth of field at wider apertures for the same field of view. Much of my subject matter benefits from that.)