The Olympus E-M10 Mark II is a mirrorless camera introduced in september 2015; it features a 4/3 sensor (17.3 x 13.0 mm) capable of 4608 x 3456 pixels, an OLED electronic viewfinder with 2.36 Mpixels and a 3.5 inches touch screen. A feature that distinguishes this camera from other mirrorless ones, is the presence of two adjustment dials (in addition to the one which selects the mode and the on/off/flash lever). The dials, like the three Fn buttons, can be freely assigned among many functions.

The camera, in combination with the M.ZUIKO 12-42 mm pancake lens (28-84 mm equiv.), is extremely compact and portable.

Pros ad Cons
	Good viewfinder with 2.36M-dot, diopter adjustable. Very compact size: 120x83x75 mm, 514 g (with the 12-42mm pancake lens). Two big dials easily operated by fingers, while keeping the eye into the eyefinder. Can be configured by the user: e.g. use the rear dial to choose the shutter speed and the front dial to adjust the exposure.
	Saving or loading of custom camera settings is not supported by the OM Workspace software. Starting the playback requires full activation of the camera (the M.Zuiko pancake lens extends the zoom). The menu to handle the Mysets is sub-optimal: saving (overwriting) of the settings can be activated by mistake instead of loading them. Cannot delete a range of photos, must select all of them.

• Specifications Olympus E-M10 Mark II - (here a PDF local copy).
• Pulsante multi function
• ISO Extension
• Quick Sleep problem in viewfinder mode
• Problema Quick Sleep Mode in modalità viewfinder
• Impostazioni Speciali
• Playback, pulsanti INFO e OK
• Fill-in Flash
• Olympus Workspace on GNU/Linux
• Fotografare un soggetto in movimento
• Modalità video
• Nome dei file
• Esposizione nel bosco
• Flash integrato
• Menu nascosto: contatore scatti
• Messa a fuoco automatica
• A manual lens on a mirrorless camera
• The Pergear 7.5mm F2.8 Fish-Eye
• Better photos from RAW files than from in-camera JPEGs
• Olympus E-M10 WiFi Protocol API

The Olympus E-M10 Mark II has two shutter modes called Anti-Shock and Silent. The following picture shows the Anti-Shock/Silent page of the Advanced shooting options menu:

To fully understand the meaning of these modes, you need to be familiar with some concepts.

• Mechanical shutter - The E-M10 has a mechanical shutter located between the lens and the sensor. The shutter is open during the Live View framing, because we need to see the image captured by the sensor, either on the monitor or into the viewfinder. When we push the shutter button, the shutter closes and all the sensor's photodiodes are powered-on; then the shutter opens just for the exposure time. All these movements produce the familiar sound of the mechanical shutter. Once the exposure is completed, the electronic can read sequentially all the rows of photodiodes, getting the values of acquired light.
• Front and rear curtains - The mechanical shutter is composed of two curtains, made of horizontal blades. The first one, located toward the lens, is responsible of starting the sensor exposure; the second one, located toward the sensor, is responsible of ending the exposure. These two movements are both bottom-up, and they are required to allow an equal exposure of all the photodiode rows.
• Electronic shutter - In a digital camera, a mechanical shutter is not actually required: the sensor can be read line-by-line. You start the exposure of a row of MOS photodiodes by turning it on, and you end the exposure by reading the values of the captured light. The rows are scanned one after the other, so it is called a rolling shutter. Because there are not moving mechanical parts, the operation can be very quick and there are no vibrations nor acoustic noise.
• Electronic front-curtain shutter (EFCS) - The movement of blades of the first curtain in a mechanical shutter, can introduce a vibration which can lead to blur in the photograph, especially with very long focal length lenses. The second curtain is not so critical: its vibration occurs when the exposure is already ended. So it is possible to use the electronic shutter in place of the first curtain to start the exposure, and the mechanical second curtain to end it. This prevents the shock of the mechanical shutter and shorten the acquisition time of a fully electronic shutter.
• The rolling shutter effect - Using a rolling electronic shutter, the photodiode rows are not exposed all at the same time, but sequentially, e.g. from top to bottom. This means that the rows are acquired at slightly different times, eventually producing artifacts with moving objects or rapid lights events (lightning or the flickering of fluorescent lamps).

Rolling shutter effects on photos from commons.wikimedia.org:

Once you understand the concepts above, you can understand the Olympus E-M10 settings.

• Activating the Anti-Shock feature (symbolized by the diamond, from the playing cards suit), you enable the electronic front-curtain shutter.
• The electronic front-curtain shutter is actually enabled only for exposure times from 1/320 to 60 sec. For shorter exposure times, the mechanical shutter will automatically be selected.
• It is also possible to enable a delay from the button press to the actual shutter activation, to avoid the shake produced by the button press. The delay can be from zero to 30 sec.
• This feature reduces the vibrations caused by the front-curtain blades movement and possibly by the button press, without incurring too much into the rolling shutter effect. The acoustic noise from the mechanical shutter remains.

• Activating the Silent feature (symbolized by the heart, from the playing cards suit), you enable the fully electronic shutter. This feature is available for exposure times from 1/16000 to 60 sec.
• It is also possible to enable a delay from the button press to the actual shutter activation, to avoid the shake produced by the button press. The delay can be from zero to 30 sec.
• This feature eliminates the vibrations caused by the shutter curtains and possibly by the button press, but incur into the rolling shutter effect. The acoustic noise from the mechanical shutter is suppressed.

• To prepare the Anti-Shock and Silent modes, press the Menu button and select Advanced shooting options ⇒ Anti-Shock/Silent. Here you can set the time delay between button press and shutter activation, or you can disable the features altogether. (setting them to Off).
• When the Noise Reduction for Silent mode is set to AUTO, it means that the mechanical shutter could still be activated in Silent mode, if you use exposure times of 4 seconds or more. The camera closes the shutter to acquire a black frame and to apply optical noise reduction to the image.
• From Super Control Panel, select the Sequential shooting/Self-timer option. Here you can choose the preferred mode with eventually the Anti-Shock or Silent variant applied.

• Silent Shutter Em-10 Mk II?
• Silent vs. Anti-shock vs. normal in OMD E-M1
• Electronic shutter, rolling shutter and flash
• Electronic Front-Curtain Shutter Explained
• Shutter Speed, What you should know about
• The Rolling Shutter Effect Videos

The default behavior for auto focus and auto exposure is to press the shutter button halfway: the camera performs both AF and AE, keeping the values locked while the button is pressed halfway. Then you can change framing and shoot by pressing the button completely.

This behaviour can be separately changed for the three focusing modes: S-AF, C-AF an MF (single and continous auto focus, manual focus); the relevant menu is Custom Menu ⇒ A. AF/MF ⇒ AEL/AFL.

The default is mode1 for all the three focusing modes. Automatic exposure and focus are both performed when the button is pressed half way (only the exposure is performed in manual focus, obviously):

If you want only the auto focus function when the button is pressed half way, you can choose mode2. The exposure is not locked, it changes as you change the framing until you press the button completely:

In any case you can have a button assigned to the AEL/AFL function (e.g. Fn1); so you can always do an Auto Exposure Locking regardless the shutter button half way, using the Fn1 button.

Finally there is the mode3, which substantially is like mode2, but it inverts exposure with focus. Pressing the shutter button half way performs only the auto exposure, the focusing is delayed until the full button press. In this case, the AEL/AFL button (e.g. Fn1 in the example above) performs the Auto Focus Locking, not the exposure. This is called Back Button Focus.

Beside the Scene mode called Portrait (selectable when the mode dial is into the SCN position), there is also a Picture mode named Portrait, selectable from the Super control panel. According to the article E-5 "Natural" and "Portrait" Mode Comparison (wich describes the Olympus E-5) “it reduces contrast by slightly lifting shadow areas, which has the effect of softening the detail very slightly – but not too much. It also warms the image slightly which improves skin tones by decreasing the red hue”.

Traditionally the f-stop scale is composed of values which distantiate each other by halving the light that is allowed to come in. A value of f/1.0 means that the lens aperture (the hole diameter) is equal to the focal lenght. Each following stop value is obtained by multiplying the previous one by the square root of 2. So the value f/1.4 means that the aperture is obtained by dividing the focal lenght by 1.4, and so on with f/2.0, f/2.8, f/4.0, f/5.7, … The minimum aperture is usually obtained dividing the focal lenght by 16 or 22, thus the f/16 or f/22.

The Olympus E-M10 have aprture stops at 1/3 of each full stop values:

The OLYMPUS Image Share Android app has a very poor rating from users (2,7 out of 5 stars, at present). Nevertheless I downloaded the big, fat app (over 50 Mb) to give it a try.

The app will require the following Android permissions:

• Storage read and write, used to download photos from the camera to the phone.
• Access to camera to read the QR code used in pairing with the camera.
• Record audio via the microphone, used for the timer?
• Location is used only to share our position with friends. To add geotag to photos it is required to install also the OLYMPUS Image Track app (which has an orrible user's score of 1,9 out of 5!).

The app will collect usage information and send it to the vendor:

• Model and firmware version of connected cameras.
• Operating system and software versions.
• Language, geographical region and app uasge statistics.

It should be possibile to disable information discolusure by disabling Impostazioni ⇒ Invia dati di utilizzo.

• dcraw
• rawtherapee
• darktable
• digikam
• ufraw
• lightzone (missing in Debian)
• rawstudio (missing in Debian)

dcraw -i -v PC150102.ORF

Filename: PC150102.ORF
Timestamp: Sun Dec 15 11:27:45 2019
Camera: Olympus E-M10MarkII
Owner: Niccolo Rigacci                                                
ISO speed: 200
Shutter: 1/2000.0 sec
Aperture: f/3.5
Focal length: 14.0 mm
Embedded ICC profile: no
Number of raw images: 1
Thumb size:  3200 x 2400
Full size:   4640 x 3472
Image size:  4640 x 3472
Output size: 3472 x 4640
Raw colors: 3
Filter pattern: RG/GB
Daylight multipliers: 2.155587 0.934705 1.481107
Camera multipliers: 2.015625 1.000000 1.671875 0.000000

• Olympus Picture Modes
• i-Enhance, Vivid, Natural and Muted comparison
• Understanding Canon RAW .CR2 files
• Olympus E-M10 - Tech Info