Om System OM-3 ASTRO Camera Instruction Manual

Overview

The OM-3 ASTRO Camera is a dedicated astrophotography camera designed for photographing starscapes, constellations, nebulae, and other celestial subjects. Its improved transmission of Hα light at 656 nm helps record stronger reddish tones, making emission nebulae and other deep-sky subjects more vivid.

This camera is intended primarily for night-sky photography. White balance can be adjusted, but natural color reproduction is not guaranteed for ordinary daylight subjects, so the OM-3 ASTRO is best used for astrophotography rather than general-purpose photography.

Specifications

• Model: OM-3 ASTRO
• Sensor: 20.4-megapixel stacked BSI Live MOS sensor
• Processor: TruePic X
• Hα transmission: Optimized for the 656 nm Hα wavelength
• Image stabilization: Built-in five-axis stabilization with up to 7.5 stops of compensation
• Monitor: 3.0-inch vari-angle touchscreen with approximately 1.62 million dots
• Video recording: 4K, C4K, Full HD, and high-speed Full HD modes
• Weather protection: IP53-rated sealing
• Freeze resistance: Operation supported down to -10°C
• Autofocus: Cross-type phase-detection and contrast autofocus with 1,053 focus points
• ISO range: Approximately ISO 80 to ISO 102400, with the default automatic range set from ISO 200 to ISO 25600

Detailed Description

The OM-3 ASTRO uses an optical design tuned for astrophotography. Compared with the standard OM-3, its improved Hα transparency allows more of the red light emitted by many nebulae to reach the sensor. This makes it easier to record reddish structures while retaining the camera’s normal exposure and focusing controls.

The camera includes dedicated controls for night-sky framing and focusing. Night Vision raises the visibility of dark skies and foreground landscapes on the monitor, while Starry Sky AF helps focus on stars. A magnified display can be activated for precise manual focusing, and Focus Ring Lock can prevent accidental focus changes after the lens has been set.

Astrophotography functions are organized around Custom modes C1, C2, and C3. These modes combine shooting, focus, exposure, white balance, stabilization, and display settings for different types of night-sky work.

Safety

• Read the camera instructions before operation, especially when using specialized astrophotography features or mounting accessories.
• The body mount filter is an optional accessory designed specifically for attachment near the OM-3 ASTRO body mount. Read the filter’s own instructions before installing or using it.
• Do not use two body mount filters at the same time.
• Short-focal-length lenses may produce a washed-out appearance around the edges when used with a body mount filter.
• High-resolution stacking requires multiple exposures and may not produce the intended composite in every scene.
• When using stacking modes, secure the camera on a tripod or equatorial mount whenever possible.
• The displayed monitor or EVF brightness and color may differ from the final recorded image.

Setup and Operation

Prepare the camera

Attach a compatible lens, insert a charged battery and recording media, and select an appropriate Custom mode. Basic camera operation follows the standard OM-3 procedure, while the C1 to C3 presets provide settings intended for specific astrophotography situations.

At the default setting, the Fn lever is assigned to Mode 1. Moving it to position 2 allows the dial to adjust ISO sensitivity. This is useful when changing exposure conditions quickly during a night session.

Frame a night scene

Activate Night Vision with its assigned button when working in darkness. The feature brightens the displayed stars and foreground scenery so the composition is easier to judge without changing the brightness of the recorded file.

The default monitor brightness is set to -7 to reduce eye strain and preserve night vision. Increase the display brightness only when the scene or recorded images are too difficult to inspect.

Focus on stars

Press the Starry Sky AF button to focus on stars automatically. For manual refinement, activate the magnified display with the Fn button and adjust the lens focus ring until the stars appear as sharp points.

After focusing, use Focus Ring Lock to disable focus-ring operation. This helps prevent accidental focus movement when handling the camera or changing the composition. Press the control again to release the lock.

Use Custom modes

The factory presets are organized as follows:

• C1 — Celestial Body Stacking: Intended for detailed nebulae and constellations. It uses a 12-shot composite and is configured around a 4-second shooting standby time, F1.2 or the lens’s maximum aperture, 30-second exposure, and ISO 3200.
• C2 — Starscape Stacking: Intended for a detailed balance of stars and terrestrial scenery. It also uses a 12-shot composite and a 4-second shooting standby time, with a typical F2, 30-second, ISO 3200 exposure combination.
• C3 — Handheld Starscape: Intended for quick, casual starscape images from a single exposure. It uses a 1-second shooting standby time and a typical F1.2 or maximum-aperture, 4-second, ISO 6400 combination.

Exposure, focus, and other settings can be changed to suit the lens, subject, and desired effect. Clearing a Custom mode restores its default settings, including its associated Color Profile.

Apply Color Profiles

Set the Creative Dial to COLOR to use the astrophotography Color Profiles. COLOR1 is tuned for celestial bodies and emphasizes red tones for nebulae. COLOR2 is tuned for starscapes and aims for balanced star-field color.

• C1 + COLOR1: Recommended for detailed celestial bodies
• C2 + COLOR2: Recommended for high-definition starscapes with stacking
• C3 + COLOR2: Recommended for easy, single-shot starscapes

COLOR1 and COLOR2 can be modified or overwritten. The recommended default combinations are a practical starting point, but exposure and color preferences may require adjustment.

Choose a white balance

The astrophotography presets include white balance values suited to night-sky subjects. The recommended combinations use approximately 2800K with a G6 shift for many starscape and celestial-body settings, while a 3500K setting with B7 and G7 shifts is also available in the preset group. Adjust white balance when the sky or foreground appears too warm, too cool, or otherwise different from the intended result.

Use stacking and stabilization

Handheld High Res Shot combines 12 exposures into one high-definition, lower-noise image with a single shutter release. C1 and C2 use this stacking approach, so the camera should remain stable during the entire sequence. A tripod or equatorial mount is recommended.

In C1 and C2, image stabilization is automatically configured as S-IS AUTO with Handheld Assist enabled. For C3, turn image stabilization off when the camera is mounted on a tripod or equatorial mount to avoid unwanted stabilization movement.

Use body mount filters

The optional BMF-LPC01 Light Pollution Filter reduces the influence of artificial lighting from streets and cities, helping the night sky appear cleaner. The BMF-SE01 Soft Filter diffuses bright point sources, making stars appear larger and softer while emphasizing their colors.

Install only one body mount filter at a time, and check the filter instructions before attaching it. With short-focal-length lenses, a filter may cause brighter or washed-out edges in the image.

Recommended display settings

• Night Vision: On
• Monitor brightness: -7 by default
• EVF Auto Luminance: Off
• EVF Auto Switch: On
• MF Assist magnification: On
• Grid display color: Red preset, with the default red grid setting

Troubleshooting

Stars look blurred

Activate Starry Sky AF or use the magnified display to refine manual focus. Once focus is correct, engage Focus Ring Lock. Also check that the camera has not moved during exposure and that the shutter standby delay is long enough to prevent release vibration.

The image is blurred after pressing the shutter button

Use the shooting standby time provided by the selected Custom mode. C1 and C2 use a 4-second delay for the multi-shot composite, while C3 uses a 1-second delay. Keep the camera on a stable support and avoid touching it during the delay and exposure sequence.

The stacked image is not as expected

Confirm that the camera and subject remained stable throughout all exposures. Moving foreground objects, changing sky conditions, wind, or an unsuitable composition can affect the composite. Use a tripod or equatorial mount and repeat the sequence under steadier conditions.

The recorded colors look unnatural

The OM-3 ASTRO is optimized for astrophotography, particularly subjects containing Hα light. Review the selected white balance and Color Profile, then try COLOR1 for stronger nebula reds or COLOR2 for a more balanced starscape appearance. Ordinary subjects may not display natural color even after white balance adjustment.

The display is too dark

Night Vision and the reduced monitor brightness are intended for dark-location shooting. If recorded images or menus are difficult to inspect, raise the monitor brightness temporarily. Remember that display brightness does not change the exposure of the captured file.

Pros & Cons

Pros

• Enhanced Hα transparency for stronger reddish nebula detail
• Dedicated Custom modes for handheld, starscape, and celestial-body photography
• Starry Sky AF, Night Vision, focus locking, and magnified manual focus support
• In-camera 12-shot high-resolution stacking
• Optional light-pollution and soft filters for specialized night-sky effects
• Five-axis stabilization and weather-sealed construction for flexible field use

Cons

• Color may be unsuitable for normal daytime subjects
• Stacking modes require a stable setup and take longer than single-shot capture
• Body mount filters cannot be combined, and short lenses may show edge washout when a filter is installed
• Default night display settings can appear too dim when reviewing images in brighter surroundings