How We Solve Problems – Fixing the Broken Battery Door of the Blackmagic Pocket Cinema Camera 4K

We go through a lot of gear here at Lensrentals. Like, a LOT a lot. Even during these slow winter months, we’re shipping multiple hundreds of orders in and out every day. This puts us in a pretty unique position. Since our equipment goes to so many different people and gets used in so many different ways, manufacturing defects often become clear to us well before the manufacturer is aware of them. Often these defects are just threads that strip easily or plastic parts that break, things we can’t correct necessarily but can at least plan for. In those cases we just order a ton of spare parts and replace them as needed. Sometimes, though, we’re able to go a step beyond replacement parts by proactively solving a problem in-house before it becomes an issue for our customers. Case in point: the Blackmagic Pocket Cinema Camera 4K.

Unfortunately, these cameras shipped with a slightly faulty battery compartment door. Due to the fact that the latch mechanism is a single piece of plastic rather than a sturdier spring-assisted mechanism, pressure from the top (by, say, a battery) or a bump from the side will cause the door latch to open, releasing the battery and shutting down the camera. I believe this is what’s referred to in the industry as a “cost-saving measure.”



A strip of gaffe tape will solve the issue in the short term, but that doesn’t look great, and we’d hate to recommend relying on a single piece of tape to keep your whole camera from shutting down in the middle of a shot, so we thought we’d come up with something more permanent.

Solving the Problem

Some of our more eagle-eyed video customers may have noticed that we recently came into possession of a 3D printer. We’ve been using it here and there to make parts we couldn’t find elsewhere. You’ll see our plastic handiwork on the body cap if you order an Alexa Mini brain from us.

Or on the 1/4 20 mount affixed to our Tentacle Sync E.

When we realized the fix could be as simple as just replacing a part in the battery door latch, Kris, our resident 3D-printing expert, got straight to work prototyping. It took a few rounds of trial and error, but we eventually came to a solution that we think will work. All we have to do is remove the old latch and replace it with our sturdier 3D-printed version.

The fixed battery latch, with internal spring system in place.


This is a simple and relatively small fix, I know, but we’re proud of it around the office because we think it’s indicative of the care and attention to detail we try to apply to your orders every day. There are a lot of options out there for gear rental. We thank you for continuing to choose us, and we look forward to seeing the incredible work you do with our gear this year. As for the latch fix, it’ll come pre-installed in any Blackmagic Pocket Cinema 4K rented from us from now on. Again, as a small expression of our gratitude for your business, here’s a link where you can download the design and print one of your own, including instructions on how to install it. From Lensrentals, happy holidays and happy shooting.


Update: “Blackmagic has reached out to us about this issue. According to their Director of Sales, it was a manufacturing defect that has since been rectified. Customers with defective battery doors should contact Blackmagic Design Customer Support. They will be more than happy to send replacement doors for any affected cameras.”



Author: Ryan Hill

My name is Ryan and I am a video tech here at In my free time, I mostly shoot documentary stuff, about food a lot of the time, as an excuse to go eat free food. If you need my qualifications, I have a B.A. in Cinema and Photography from Southern Illinois University in beautiful downtown Carbondale, Illinois.

Posted in Equipment
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  • GuyWith

    Blackmagic Design Pty. Ltd. owes you people many, many beers.

  • Richard

    Fragile pieces like this should be sold in a pack of 3 for $10 a piece until they re-design the thing.

  • stanislawzolczynski yes

  • Athanasius Kirchner

    Well done! I expect the Chinese are hard at work now making clones of your 3D-printed solution to sell on FleaBay 😛

  • Sarah Müller

    Who posed as model for that Santa gift?

  • Darkness

    I think Blackmagic should print them and send them out to all Pocket 4k customers. Putting the responsibility of this on the customer, in this case lens rental, is sour grapes. It’s BMD’s production flaw, they should resolve it free of charge, WITHOUT having to send the entire unit back to them and especially because the battery door is easily removable. Great camera, very nice image, but common BMD. No internal spring?

  • Dirty Santa is dirty!

  • Hunter45


  • Stanislaw Zolczynski

    Latches or not, with exception of prof Nicanon solution a bit of gaffa gives you a piece of mind

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