1. Introduction
The AstrHori AH-M1B Light Meter is a compact and lightweight exposure meter designed for photographers using various camera types, including vintage and rangefinder cameras. It features an OLED display and intuitive controls for adjusting ISO, aperture, and shutter speed, ensuring accurate exposure measurements.
Figure 1: The AstrHori AH-M1B Light Meter features a compact design with an OLED display and a control dial.
2. Product Overview
2.1 Key Features
- Compact and Lightweight: Bronze plate body, high-quality metal construction, weighing approximately 59g.
- OLED Display: Clear 0.66-inch OLED screen for easy readability.
- Cold Shoe Mount: Compatible with various cameras, ideal for vintage Leicas and similar rangefinder cameras. Can also be handheld.
- Dual Energy Saving: Built-in 120mAH lithium battery provides 12 hours of continuous metering. Features low-power sleep mode and automatic shutdown.
- High Precision Metering: Approximately 30° average metering with a single metering time of ≤0.5s.
- Flexible Adjustment Ranges:
- Metering Range (ISO100): EV1~EV22
- Aperture Adjustment: F1~F32
- Shutter Time Adjustment: 32s~1/8000s
- ISO Adjustment: ISO5~ISO6400
- Exposure Compensation: +3EV~-3EV
- A/T Mode Switching: Easily switch between Aperture-priority and Shutter-priority modes.
2.2 Physical Components
Figure 2: Multiple views of the light meter highlight its small size and ergonomic design, making it easy to handle and integrate with camera setups.
Figure 3: This infographic provides key product details: Brass material, 0.66-inch OLED screen, approximately 48g weight, 30° average metering, A/T real-time metering, Type-C charging port, and a 120mAh built-in lithium battery.
3. Setup
3.1 Charging the Device
The light meter has a built-in 120mAH lithium battery. To charge, connect a 5V power supply via the USB Type-C interface. A full charge typically takes about 40 minutes when using a computer's USB port.
3.2 Mounting to a Camera
The light meter can be attached to a camera's cold shoe mount. The flexible cold shoe base allows for adjustment to prevent slippage during use.
Figure 4: The flexible cold shoe base allows for adjustable positioning, ensuring secure attachment to different camera models without slippage.
4. Operating Instructions
4.1 Power On/Off
To power on, press the main button. The device will enter a low-power sleep mode after 25 seconds of inactivity and automatically shut down after approximately 3 hours of sleep. Click the button to wake it from sleep mode.
4.2 Mode Switching (A/T Mode)
Double-click the main button to switch between "A" (Aperture-priority) mode and "T" (Shutter-priority) mode. In "A" mode, set the aperture value using the dial, and the meter calculates the recommended shutter time. In "T" mode, set the shutter time using the dial, and the meter calculates the recommended aperture value. Adjustments can be made in 1/3 gear increments.
Figure 5: This diagram illustrates the primary button functions for mode selection and parameter adjustments.
4.3 ISO Adjustment and Exposure Compensation
- ISO Adjustment: Double-click the key, then press it again for about 0.5 seconds to switch to ISO adjustment. Set the ISO through the dial. The minimum adjustment is 1/3 gear.
- Exposure Compensation: Double-click the key, then press it again for about 3.5 seconds to switch to the exposure compensation setting. Adjust the exposure compensation by dial to change the recommended value calculated by the light meter. The minimum value can be adjusted by 1/3 EV.
4.4 Metering Operation
The light meter supports both real-time and one-key metering. In real-time metering, the device continuously measures ambient light and displays recommended parameters. For one-key metering, a single press of the button initiates a measurement.
Figure 6: The light meter offers both real-time metering, where parameters are continuously calculated, and one-key metering, which provides a single measurement upon activation. A lock icon indicates when measured parameters are held.
4.5 Official Product Video
Video 1: This video provides a visual guide to the AstrHori light meter, showcasing its design, key functions, and how it integrates with a camera.
5. Specifications
| Feature | Detail |
|---|---|
| Model Number | CGB-B-S-FT |
| Material | Brass |
| Display | 0.66-inch OLED |
| Weight | Approximately 59g (5.3 ounces) |
| Battery | Built-in 120mAH Lithium Battery |
| Charging Port | USB Type-C |
| Continuous Metering Time | 12 hours |
| Metering Angle | Approximately 30° (average metering) |
| Single Metering Time | ≤0.5s |
| Metering Range (ISO100) | EV1~EV22 |
| Aperture Adjustment Range | F1~F32 |
| Shutter Time Adjustment Range | 32s~1/8000s |
| ISO Adjustment Range | ISO5~ISO6400 |
| Exposure Compensation Range | +3EV~-3EV |
| Package Dimensions | 5.94 x 5.91 x 2.05 inches |
6. Maintenance
To ensure the longevity and optimal performance of your AstrHori AH-M1B Light Meter, follow these maintenance guidelines:
- Cleaning: Use a soft, dry cloth to clean the exterior of the device. Avoid using liquid cleaners or solvents, as they may damage the finish or internal components.
- Storage: Store the light meter in a cool, dry place away from direct sunlight, extreme temperatures, and high humidity. When not in use for extended periods, ensure the device is fully charged before storage.
- Handling: Handle the device with care to prevent drops or impacts, which could damage the OLED display or internal circuitry.
7. Troubleshooting
If you encounter issues with your AstrHori AH-M1B Light Meter, refer to the following common troubleshooting steps:
- Device Not Powering On: Ensure the battery is charged. Connect the device to a USB Type-C charger for at least 10 minutes. If the issue persists, contact customer support.
- Inaccurate Readings: Verify that the metering mode (A/T) and ISO settings are correctly configured for your shooting conditions. Ensure the light sensor is clean and unobstructed.
- Display Issues: If the OLED display is dim or unresponsive, try recharging the battery. If the problem continues, contact customer support.
- Buttons Unresponsive: Ensure the device is not in a locked state (if applicable). If buttons remain unresponsive after a restart, contact customer support.
8. Warranty and Support
For warranty information, technical support, or service inquiries, please refer to the official AstrHori website or contact your authorized dealer. Keep your purchase receipt as proof of purchase for warranty claims.
Figure 7: The package includes the AstrHori light meter, a USB Type-C charging cable, and the user instruction manual.
