OM System OM-1 – Histogram and Exposure Preview
Introduction
Histogram and tonal value preview in live view are powerful features of the OM System OM-1. With those, setting the exposure and avoiding clipped shadows and highlights is a breeze.
Live View Settings for Exposure Preview
In [Standard] Live View mode, the OM-1 provides a preview of the following settings:
Picture Mode or Art Filter
Tonal values
White balance
Even if the camera is set to record RAW only, the OM-1 will not provide a preview of the 12-bit RAW file with all the image data, but a preview of the 8-bit JPG.
In order to better approximate the image data recorded in the RAW file, a so called “flat preview” is needed.
Settings for “Flat Preview”
Picture Mode
Muted
Contrast -2
These settings ensure that the wider tonal range of the RAW-file is better represented. Still, the RAW file has more dynamic range than the “Muted” preview.
White Balance
Set the correct white balance for the scene
When in doubt, choose [WB Auto]
The white balance setting has an impact on the tonal values in Live View and is ideally set to the correct value.
OM System OM-1 - WB Auto
OM System OM-1 - incorrect WB; note the Histogram
Clipping Warning in Live View
The OM System OM-1 can display a clipping warning in Live View. This option is called [Highlight&Shadow] and is found under [Info Settings].
OM System OM-1 - enabling histogram & clipping warning (1)
OM System OM-1 - enabling histogram & clipping warning (2)
Histogram Exposure Warning
As the simulated Live View is related to the 8-bit JPG output, each channel can have values ranging from 0 to 255.
The thresholds can be configured under the [Histogram Settings] and should be set to:
Shadow [0]
Highlight [255]
When in Live View, the OM-1 will now display areas with tonal values of 0 in blue and areas with tonal values of 255 in orange, effectively providing a clipping warning.
OM System OM-1 - histogram settings
OM System OM-1 - histogram settings
Histogram
When combined with the flat preview and clipping warning, the Live View Histogram can provide an additional layer of information to judge the exposure of a scene. It can be activated under [Info Settings].
Color Codes – Histogram
Blue – tonal values of [0]
Orange – tonal values of [255]
Green – spot metering reading
When spot metering is disabled, the green portion of the histogram refers to the center 2% of the image frame.
OM System OM-1 - histogram and clipping
Recommendations
I like to configure one information display of my OM-1 to display both the histogram and the [Highlight&Shadow] warning.
With this information, the exposure can be set reliably under most circumstances.
Limitations
It is important to note that the OM-1 can automatically adapt the exposure simulation slightly to maintain functionality, for example when using the spot meter in manual mode with an over- or underexposed scene. This also affects the clipping warning and histogram, as both are generated based on the preview in the viewfinder.
The most accurate and reliable way to set the exposure is therefore the camera’s internal exposure meter or an external exposure meter.
Also, Live View does not simulate exposure compensation values exceeding +/-3 EV, although the camera accepts exposure compensation values up to +/-5 EV.
OM System OM-1 - +3 EV Live View
OM System OM-1 - +5 EV Live View; identical with +3 EV
