Some random info about the Olympus OM-D E-M1 Mark III

Last updated on April 12, 2020.

I recently purchased an Olympus OM-D E-M1 Mark III with the M.Zuiko 12-100mm f/4 PRO lens, and have additionally purchased an M.Zuiko 25mm f/1.8 lens to go with it. I've been shooting a lot with this camera, even in the midst of this coronavirus pandemic (before New York essentially went into lockdown) and have been thoroughly enjoying it.

This post is just to serve as a space for random notes and information about the camera. It isn't going to be as polished as my usual content, but perhaps some of this information will be useful to others. I'll be updating it as needed.

• Sensor readout speed is normally about 1/60s. If the ISO sensitivity is set to 8000 or higher, it is about 1/30s. This is reflected in the flash sync speeds when shooting in silent mode (♥ heart symbol), which are 1/50s at ISO 6400 and below and 1/20s at ISO 8000 and above. In comparison, the flash sync speed of the mechanical shutter is 1/250s. (Note that flash is disabled by default in silent mode but can be enabled in the menu, under Shooting Menu 2, Anti-Shock[♦️]/Silent[♥].)
• Accessing the camera's hidden service menu, including the shutter count, is actually simpler than what some online guides may state, e.g. this article. To do this, hold the Menu button when turning on the camera, then open the menu, open the brightness settings (Setup Menu, fourth item), and press OK. (There is no need to press Right or Info on this screen.) Then press Up, Down, Left, Right, and the shutter button, in that order. From here, pressing Right will show the camera's internal counters:
• MS is the number of mechanical shutter actuations. This does not include shots taken with the electronic shutter, and does account for operations like pixel mapping (which requires four shutter actuations) which use the mechanical shutter. This means that the value displayed here can be relied on as an accurate shutter count. (Older Olympus cameras used R for shutter releases, which wasn't an accurate shutter count because it included electronic shutter usage.)
• S (strobe) is the number of times the camera has fired a flash (there's no pop-up flash but the camera does count shoe-mounted flashgun usage).
• U is the number of times the camera has activated the Supersonic Wave Filter, which removes dust from the sensor. This can be used to estimate the number of power cycles because the camera activates the SSWF every time it is turned on; however, the SSWF is also activated during pixel mapping (Custom Menu J1) so it won't be an exact value.
  
• The camera supports USB Power Delivery and can be charged via its USB-C port.
• USB PD is not required to charge the camera, only to operate it. You can charge the camera using any normal USB power source. For best USB charging performance, use a charger rated at 1.5A or higher at 5V. Note that this is still somewhat slower than using the BCH-1 dedicated charger.
• Only the body battery can be charged via USB. You can't charge the battery inside an HLD-9 power battery holder (battery grip) this way.
• To operate the camera using USB PD, the power supply must be rated at 27W or higher (3A@9V or 2A@15V). Not all USB PD power banks can supply this much power; an 18W power bank will not work (as demonstrated by Rob Trek). The camera will show the USB PD power mode it's negotiated when you select USB PD from the USB menu.
• USB PD operation requires a battery in the camera body with at least 11% charge. If the battery is low or depleted, turn off the camera and let it charge for a bit before using USB PD.
• The camera will not charge while operating from USB PD. It will only charge when it is powered off.
• Using an Anker dual port (USB-A plus USB-C) charger on a Kill-A-Watt meter, I was able to measure the camera's power draw during various operations. While these values are probably going to be higher than the actual amount of power drawn when operating from the battery due to power efficiency differences, they should provide a sense of what to expect when it comes to battery life. (For reference, the BLH-1 battery has a nominal capacity of 12.7 Wh.) All measurements were made with the M.Zuiko 25mm f/1.8 lens attached; power draw is likely to be higher with a lens that supports Sync IS, such as the M.Zuiko 12-100mm f/4 PRO, which I have not tested with.
• Base idle power is about 4.8W with the LCD and 4.9W with the EVF. In the menus and during playback, the camera draws about 3.1W.
• Using Frame Rate: High (custom settings page D2), which runs the EVF at 120 fps, adds about 0.5W when shooting through the EVF for about 5.4W power draw.
• Holding down the shutter button halfway with image stabilization enabled adds about 0.5W of power draw. (This will probably be higher with a Sync IS lens.)
• Pro Capture can draw a significant amount of power, especially in High mode. Power draw was as high as 7.1W with the shutter button pressed halfway, and is likely to be even higher if using a Sync IS lens.
• The maximum power draw observed was during continuous shooting with the mechanical shutter, at upwards of 9W. Note that this is only during actual operation of the mechanical shutter, so this kind of power draw will only happen in short bursts.
• Unfortunately, I do not have an Olympus FL-LM3 to test power draw when a camera-powered flash unit is attached to the camera.
• The dedicated charger BCH-1 is supposed to light up green when the battery is fully charged. In reality, the battery may not actually be completely full: if you remove the battery from the charger immediately after the light turns green, it'll read about 8.20V on my multimeter, which isn't quite a full charge, even if it registers 100% on the camera. Giving it an additional 30 minutes will fully top off the battery, at which point the battery will measure at about 8.32V.
• Note that if the battery reads 100% on the camera, putting it on the charger won't do much: it'll just light up green. The charger will charge the battery if the reported charge is 99% or below.
• The M.Zuiko 12-100mm f/4 PRO lens, while optically stellar, has some quirks of its own.
• The focus clutch provides a mechanical feel with hard stops at each end but is strictly focus by wire and requires the camera to be powered on function.
• While it does behave very much like a traditional manual-focus lens in this mode because of the extremely high precision of the focus ring and nearly zero lag, focusing is strongly nonlinear near the minimum focusing distance. At the wide end, the transition to minimum focusing distance is abrupt; small movements result in large changes in focus, resulting in reduced focusing precision. At the long end, the lens reaches its minimum focusing distance before the hard stop is reached. This does not affect manual focusing when not using the focus clutch (using MF mode or with AF+MF enabled).
• This is because the lens tries to emulate a true parfocal zoom so that it keeps the focus distance you set regardless of your zoom setting. However, because the lens's minimum focusing distance increases with the focal length, this cannot be maintained towards the close end of the focusing range. Hence, manual focus behavior is linear for most of the focusing range but the close focusing range needs to be compressed at wider focal lengths to accommodate the shorter minimum focusing distance.
• The working distance at the close end of the focusing range at 12mm is extremely short. The official specs say it's 1.5 cm but it seems to be even less than that in my testing (somewhere around 1.0 to 1.2 cm). The lens hood will need to be removed and lighting will be very difficult. Zooming in slightly to about 15mm will make lighting a bit easier at only a small cost to maximum magnification. Beyond that point, the minimum focusing distance will start to rapidly increase.

If you have anything else to share, be sure to let me know in the comment section.

Draco