I was going to post a comparison between the TechArt and Steelsring EF to GF autofocus adapters but the latest firmware for the Steelsring has some serious bugs that need to be addressed before I can begin. I will post specifically about the Steelsring adapter soon.
Meanwhile, I wanted to provide a solution for GFX shooters… specifically, powering your camera via AC or DC power. As you may know, Fujifilm offers an AC adapter for the GFX series and it’s priced at a whopping $97.
However, there’s another option for AC wall charging. Any 14-16 volt, 4 amp power supply (65W) with a 5.5mm barrel jack and 2.5mm center pin will work just fine. These can be found all over Amazon for under $20 and will power your GFX while simultaneously charging the battery. The exact power input is specified as 4.34A at 15V for a total of 65 watts.
How did I find this? The inside of the GFX 50S USB port door has the port specs molded into it and for the DC power input, it’s labeled with “15V.”
Additionally, the Fujifilm AC power adapter’s model number is “AC-15V,” and the label on the power brick clearly states the output being “15V 4.34A,” which comes out to 65.1W total power output.
This will solve your problems if you’re a studio photographer but people out in the field wanting to shoot really long exposures, time lapses or video deserve a solution besides the battery grip. Not only is it expensive, it’s bulky and heavy, taking up space and weighing you down in the field. If only you could use a portable battery pack, aka a power bank.
The key is to find one that offers DC power through a barrel jack and has selectable voltage. Some laptops still feature proprietary plugs and standard DC barrel jacks, despite a world that’s quickly moving to USB-C Power Delivery, and there are power banks designed for powering these laptops. Be careful: do not be fooled by USB-C. The standard requires the receiving end have a certification chip to identify the device and set the voltage. Without this communication, power output defaults to 5V at 1A. Obviously this is not enough to power the GFX 50S or 50R. Life would be easier had the GFX 50S and 50R been supplied with USB-C PD charging.
Let me reiterate: the short answer is to avoid using USB-C Power Delivery power banks. Use only a power bank specifically designed for laptops with a DC barrel jack.
To begin, you will need 3 things:
- A Power Bank, aka External Battery Pack with DC output via 5.5mm barrel jack and selectable voltage whose range includes 14, 15 or 16 volts and has a total power output of at least 60 watts
- DC power cable with standard 5.5mm male barrel jacks at both ends and positive (+) center post
- Barrel jack adapter to convert the cable’s 5.5mm jack with 2.1mm positive (+) center pin to a 5.5mm jack with 2.5mm center pin
The GFX 50S and 50R use a 5.5mm female barrel jack with 2.5mm positive (+) center pin for DC power input. Operating power is 15 Volts at 4.34 Amps for a total of 65.1 Watts. A minimum of 12.6V at 4A is required to charge the internal battery while the camera is powered off or to power the camera while trickle charging the battery or not charging it at all. If your power supply doesn’t offer 15V, you can safely use 14V or 16V at 4A to simultaneously power the camera and charge the battery but this will affect the time it takes to recharge the internal battery while the camera is powered on.
The power bank I’ve settled on is the Omnicharge Omni Mobile 25600. It has selectable voltage from 12-20V and outputs via a 5.5*2.1mm DC barrel jack. There’s also a pair of USB-A ports, a USB-C input/output port for charging the power bank itself and a built-in Qi wireless charging pad. While a bit large, it’s still similar in mass to other brands of power banks of its capacity but offers a lot more connectivity. Plus, it’s right at the TSA limit for air travel. You can take this anywhere and use it to charge anything… including your GFX.
All you’ll need now is a standard 5.5*2.1mm DC cable of any length that suits your needs and an adapter to fit the 5.5*2.5mm DC port on the GFX. Both of these can be found for under $10 each.
Just follow the instructions included with your power bank to select the proper voltage, connect the power cable and watch the green led in the thumb grip light up to show that it’s charging. Powering up the camera will display either a yellow (charging) or green (charged) battery icon as it draws power from the power bank. The thumb grip LED will turn off once the battery is full.
If your voltage is incorrect, neither the LED will glow nor the charging/charged icon will be displayed on the back LCD. If your settings are REALLY incorrect, you may see some smoke before it ignites.
Just kidding. The GFX has a “smart” charging program and will not attempt to charge if the battery is full or if DC input is exceedingly far below or above the requirements.
Another benefit of the Omni Mobile, and most other high quality power banks, is pass through charging. You can connect the power bank to AC power and continuously power the camera in a studio or home setting without depleting the power bank itself. By functioning as an AC wall adapter you won’t need to buy a wall adapter specifically for the GFX.
Price? The Omni Mobile 25600 costs $120-160, cable and adapter for $10. A 45W minimum USB-C charging brick, for charging the power bank, will cost you $20-30 if you don’t have one already. Before you balk at the price, I use mine for backpacking to charge my phone, tablet, smart watch, Fujifilm GFX 50S and X-T3 batteries AND power either camera for astrophotography, time lapses and daytime filming. It’s replaced my 2 Mophie Powerstations, a total of $280, as the only power bank I need. In comparison, a genuine Fujifilm NP-T125 battery is $100 and the battery grip for GFX 50S is $499 while the GFX 50R has no provisions for a second battery.
Again, the necessary specs on the GFX 50S and 50R for those who don’t want to scroll back up for them: 15V, 4A DC input totaling 65W and 5.5*2.5mm barrel jack. It’s not compatible with USB-C charging over Power Delivery; the power bank must use a barrel jack DC output,have an output voltage of 14-16V and a nominal power output of 65W.
I got all of this info from the labels on the Fujifilm GFX 50S camera itself, the Fujifilm AC-15V power adapter for GFX and the NP-T125 battery. Because of this, I know what I’ve offered is completely factual and accurate. However, I cannot control for you and therefore I accept zero responsibility if you purchase garbage components, receive low quality counterfeit goods, or simply fuck it up and burn down your home. This is a straightforward process but if you’re bad at math and measures, fear electricity or still live with you mother, go ask an adult to do it for you.
JetCity Ninja 
Center is positive.
Alternatively, you can use a Sony NP-F970 battery with a generic plate w/ a 12v output to power the 50S and 50R. It’s a lot cheaper.
Really helpful hint! Do you know if the polarity of the connector is standard? I mean positive center, negative outer ring
I am also interested in the polarity.
As styledliving specified, it’s standard configuration, aka positive center pin. I should’ve made that clear and have amended my blog post.
As styledliving specified, it’s positive center pin. I made the assumption all would know it’s standard configuration and I was wrong to do that when I was so specific about everything else. Blog post has been amended and sorry for the late reply.