Blackmagic Design PL Mount Shim Kit
Blackmagic Design PL Mount Shim Kit is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Blackmagic Design PL Mount Shim Kit
The Blackmagic Design PL Mount Shim Kit is a critical technical accessory for cinematographers using the URSA, URSA Mini, URSA Mini Pro, or URSA Broadcast cameras. This kit is used to precisely calibrate the flange focal distance (the distance between the lens mount and the camera sensor), a process commonly referred to as "shimming" the mount.
Purpose and Functionality
In professional cinematography, focus marks on a lens must be accurate. If the distance between the lens and the sensor is off by even a fraction of a millimeter, the lens may not hit "infinity focus" correctly, or its focus scales may become unreliable.
-
Back Focus Calibration: Shims are used to adjust the camera's back focus to compensate for manufacturing tolerances in either the camera body or the specific PL-mount lenses being used.
-
Ensuring Lens Accuracy: By adding or removing shims, you ensure that a lens focused at 10 feet on the barrel is actually focused at exactly 10 feet on the sensor.
Kit Contents
The kit typically includes a selection of ultra-thin, color-coded rings that are placed behind the lens mount.
-
Set of 8 Shims: The kit contains multiple shims of varying thicknesses, allowing you to stack them to achieve a specific total thickness.
-
Baffle Tool: Some versions of the kit include a specialized tool to help remove the internal light baffle or the lens mount assembly without damaging the sensor's glass.
-
Color-Coding: Each shim is color-coded (often in shades like tan, red, or clear) to represent a specific thickness in millimeters, making it easier to track adjustments.
Compatibility
This kit is specifically designed for the interchangeable lens mount system found on Blackmagic’s high-end cinema cameras:
-
URSA Mini Pro (4.6K, G1, G2, 12K): Essential when swapping from the default EF mount to the optional PL mount.
-
URSA Broadcast G2: Critical for ensuring cinema PL glass performs correctly on the broadcast sensor.
-
Blackmagic Cinema Camera 6K (L-Mount): While the camera uses L-Mount, users who utilize the Blackmagic PL Mount adapter may require shims to ensure that adapted PL lenses maintain proper infinity focus.
How to Use the Kit
Shimming is a delicate process that should be performed in a clean, dust-free environment.
-
Mount Removal: Use a 2.0mm hex key to remove the screws holding the existing lens mount onto the camera body.
-
Placement: Place the desired shim (or combination of shims) onto the camera body, ensuring they sit flat against the mounting surface.
-
Reassembly: Re-attach the PL mount and tighten the screws in a "star pattern" to ensure even pressure.
-
Testing: Mount a wide-angle lens, set it to infinity, and check the image on a high-resolution monitor or using the camera’s focus peaking tool. If infinity focus is not achieved, the shim thickness must be adjusted.
Operational Insight
For rental houses and professional DPs, shimming is a standard part of "camera prep." Because temperature changes and physical wear can slightly shift a camera's flange distance over time, having a shim kit on hand is vital for maintaining professional standards. It is often recommended to use a Siemens Star chart or a Projector during this process to verify that the focus is sharp across the entire frame.
