WFM icon FieldMonitor: Controls copyright © 2017 Adam J. Wilt  
A wireless video monitor for iPhone
The Source Screen has controls to monitor a source (view its video feed), reload the list of available sources, change settings, and view help.

The Monitor Screen has controls to change how the picture is displayed and how the ’scopes are shown.

Source Screen

Tapping Settings on the Source screen displays the Settings menu:



Monitor Screen



   Levels (only available for camera sources)

        See About Luma Levels for more details.

Camera Controls

Panasonic cameras are supported with a limited set of onscreen adjustments. Tap the screen to hide the adjustments and see a decluttered screen. Tap again to bring the controls back. Depending on the camera’s operating mode and on-camera settings, different controls will be shown at different times, and the available control options will change.

When the Wi-Fi network is congested or the signal is weak, camera commands can be delayed or dropped. If “network timeout” appears onscreen, it is likely that commands won’t get through. Wait until “network timeout” disappears before trying to control the camera. If you frequently see “network timeout”, try some of the networking fixes discussed on the support page.

About Luma Levels

Video can be encoded with a variety of “Luminance Levels”, spanning different numerical ranges within their 8-bit (or 10-bit) signals. For example, an 8-bit “full swing” signal records black at a level of 0 and white at a level of 255, just like a JPEG image does. A “studio swing” signal puts black at a level of 16 and white at 235, the black and white levels of a Rec.709 video signal. It's also common to find “extended range” signals with black at 16 and white at 255.

In 10-bit modes, 0–255 translates to 0–1020 or 0–1023; 16–235 is 64–940, and 16–255 is either 64–1020 or 64–1023 (1020 is the true 10-bit equivalent of 255, but Panasonic displays it as 1023 in the GH5’s menus). FieldMonitor uses 8-bit terminology regardless of how your camera is set up.

Panasonics default to Luminance Levels 16-255 when recording video. If your camera does not have a Luminance Levels setting, it uses 16-255.

Cameras like the GH4 and GH5 offer all three choices when set to MOV format. In AVCHD or MP4 modes, only 16–235 and 16–255 are available; in V-Log L only 0–255 is used.

When shooting stills, and (usually, but not always) when in Movie mode but not recording, the camera uses 0–255.

Are we having fun yet?

Unfortunately, Panasonics don’t tell Wi-Fi apps which Luminance Levels are in use. In addition, the camera’s images transmitted over Wi-Fi will use different levels settings in standby and in record, and those levels will vary depending on whether the camera is in Creative Video Mode and whether it’s feeding video over an HDMI connection—and the camera doesn't communicate that information, either. Instead, you have to manually set FieldMonitor to match how your camera is set up (yes, this is an annoying, confusing hassle: I'm sorry, but there’s nothing I can do to fix it other than to give you manual controls).

FieldMonitor offers four luma ranges in its Levels settings, so that the measurements made in standby match those made while recording:

In addition, you use two switches to tell FieldMonitor whether the camera is in Creative Video Mode (the mode-dial setting with the movie camera), and whether or not you’re feeding live images out HDMI.

If the settings on the camera and in FieldMonitor don’t match, the ’scopes and false-color overlay will change when you go from standby into record or vice versa. (You can test your settings by aiming the camera at a high-contrast scene with clipped whites and deep blacks and watching the WFM as you start and stop recording: the highest and lowest levels shown on the WFM should not change).

If you're worried about mistakes, set any of FieldMonitor’s ranges other than Legal. The ’scopes and false-color will be correct whenever the camera is in record mode (though they may be incorrect in standby mode) and they'll show you exactly what levels are being recorded or sent out HDMI.

Note that Luma settings are only used to control how ’scopes and false-color interpret the image. The picture itself is unaffected (and uncorrected) by the setting, so you may often see the black level and contrast of the displayed image change slightly when you press record, or when you change Luminance Levels on the camera. Depending on the various factors discussed above, the pictures the camera sends over Wi-Fi may use any of the following luma ranges: 0–219, 0–239, 0–255, 16–235, or 16–255.

© 2017 Adam J. Wilt.  Last updated 2017.06.22