The Blackmagic Design Spares - Camera - Glass Filter EF refers to the IR-Cut / OLPF (Optical Low Pass Filter) assembly specifically for the Canon EF-mount versions of Blackmagic cameras. This part is most commonly sought for the Pocket Cinema Camera 6K (Original & G2), the 6K Pro, and the URSA Mini/Pro series.
Because the EF mount has a larger throat and a longer flange distance ($44\text{mm}$) than MFT, this glass is larger and sits deeper within the "turret" of the camera body.
Core Responsibilities
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Infrared (IR) Suppression: Blocks the infrared spectrum to prevent "IR contamination" (where dark fabrics or shadows take on a reddish or magenta tint).
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Moiré & Aliasing Reduction: On models equipped with an OLPF (like the newer 6K Pro/G2 and 12K OLPF), this glass microscopically blurs fine repeating patterns that the high-resolution sensor would otherwise "alias."
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Environmental Seal: Protects the sensitive CMOS sensor from dust, humidity, and accidental contact during lens changes.
When to Replace the EF Glass Filter
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The "Cloudy" Sensor: Over time, humidity can react with the coatings on the filter, creating a permanent haze or "fungus-like" appearance. This is a common issue in humid climates and cannot be wiped away.
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Surface Pitting: High-velocity dust (common in desert or wind-blown shoots) can create microscopic pits in the glass that cause "flaring" when shooting toward light sources.
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Oxidation/Discoloration: If your images show a consistent color cast that cannot be corrected in DaVinci Resolve, the filter's chemical coating may have oxidized.
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Cleaning Damage: Scratches from using improper cleaning tools (like a dry T-shirt or low-grade swabs) are the #1 cause for replacement.
Technical Installation Note
Repair Level: 2 (Moderate). While you are working inside the lens mount, you do not typically need to disassemble the entire camera chassis.
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The Turret System: In the Pocket 6K Pro and 6K G2, the glass is housed in a removable "turret." You remove three Phillips screws inside the mount to lift the entire glass housing out.
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Cleanliness is Mandatory: This is a "clean-room" operation. Any dust trapped between the filter and the sensor will be visible in your footage. Use a vacuum or a high-quality air blower (like a Giotto’s Rocket Blower) before and during installation.
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Gasket Integrity: Ensure the small rubber O-ring or gasket is seated perfectly. If the gasket is pinched, the glass will sit at an angle, causing one side of your image to be soft (out of focus).
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Flange Calibration (Shimming): Different thicknesses of glass change the optical path. If you switch from an IR-cut to an OLPF (or vice-versa), you may need to add or remove metal shims behind the EF mount to ensure your lens "Infinity" marks remain accurate.
Comparison: Filter vs. Sensor
| Part |
Cost |
Complexity |
Symptom |
| Glass Filter |
$~100$ USD |
Low-Medium |
Scratches, Haze, IR Polluted Blacks |
| CMOS Sensor |
$~800+$ USD |
High (Expert) |
Dead Pixels, Vertical Lines, Pink/Green Tearing |
Pro-Tip: The "Breath Test"
If you see a mark on the glass, do not immediately try to scrub it. Use a specialized sensor loupe (magnifying glass with LEDs) to determine if it is on top of the glass or etched into the coating. If a gentle wet-clean with a $24\text{mm}$ sensor swab and specialized fluid doesn't move the mark, the coating is likely damaged and the glass must be replaced.
Are you seeing a physical scratch on the glass, or is your image looking "hazy" and "soft" across the entire frame?
