the Blackmagic Design Spares - Camera - Glass Filter MFT refers to the IR-Cut/Optical Filter assembly used in Blackmagic’s Micro Four Thirds (MFT) mount cameras. This includes the Pocket Cinema Camera 4K (PCC4K), the Micro Cinema Camera, and the Micro Studio Camera 4K.
Because the MFT sensor is smaller and the flange distance is short, this glass is the only barrier protecting the sensor from the outside world. It is a frequent spare part because it is easily scratched during lens changes or cleaning.
Core Responsibilities
-
Infrared (IR) Filtration: Digital sensors are highly sensitive to IR light, which can cause "IR pollution" (blacks looking muddy or purple). This glass reflects or absorbs those wavelengths.
-
Sensor Protection: Acts as a physical seal for the sensor chamber, preventing dust and moisture from reaching the expensive CMOS/JFET sensor underneath.
-
Optical Correction: Maintains the correct "optical path" length. Removing this glass without replacing it will cause your lenses to lose "infinity" focus and perform poorly.
When to Replace the MFT Glass Filter
-
Oxidation (Glass Disease): Many older Blackmagic MFT filters (especially on the original Pocket or Micro) can develop a "hazy" or "cloudy" appearance over time due to moisture reacting with the coatings. This cannot be cleaned off.
-
Wet-Cleaning Scratches: If a piece of grit was caught on a sensor swab during a cleaning attempt, it may have left a permanent streak visible at high f-stops (e.g., $f/16$ or $f/22$).
-
Coating Delamination: If you see small "bubbles" or "peeling" on the surface, the multi-layer anti-reflective coating is failing.
Technical Installation Note
Repair Level: 2 (Moderate). While you don't always have to take the whole camera apart, you are working millimeters away from the sensor.
-
Retention Ring: Most Blackmagic MFT mounts use a small metal retaining ring or a rubber gasket to hold the glass in place. You will need a set of precision curved tweezers or a small vacuum suction tool.
-
The "Clean Room" Environment: Any dust trapped behind the glass during installation will be permanently visible in your footage. Perform this repair in a "still air" environment (like a bathroom after a hot shower has settled the dust).
-
Orientation: The glass often has a specific side that must face the sensor. Usually, the more "reflective" or "tinted" side faces the lens. Installing it backward can cause internal reflections (ghosting).
-
Avoid the Shims: Behind the filter, there are often paper-thin metal shims. These calibrate the "Flange Focal Distance." Do not lose or move these, or your lenses will not focus accurately according to their distance markings.
Comparison: Filter vs. Sensor
It is a common mistake to think the "Sensor" is scratched. In 99% of cases, it is only this Glass Filter that is damaged.
-
The Filter: A $50$–$100$ USD part that can be swapped relatively easily.
-
The Sensor: A part of the Main PCB or a dedicated Sensor Board that can cost $500$–$1,000$ USD and requires a total teardown.
Pro-Tip: The Dust Test
If you see a spot on your image, take a photo of a plain white wall at $f/22$. Then, take another at $f/2.8$.
-
If the spot stays sharp and dark at $f/22$ but disappears at $f/2.8$, the dust/scratch is on this Glass Filter.
-
If the spot is a large, blurry "blob," it is likely on the back element of your lens.
Are you replacing this because of a physical scratch, or has the glass developed a cloudy/hazy appearance?
