Camera Hack: Using WiFi SD Cards to Deliver Still Frame Grabs from a Camera

Camera Hack: Using WiFi SD Cards to Deliver Still Frame Grabs from a Camera

The problem with frame grabs is the intrusion of retrieving them from the camera. Often, a DIT or AC will have to take over the camera to generate the grabs and whisk them away on the SD card. Fortunately, for those who don't like interruptions and those who don't like interrupting, one reader has come up with a solution that utilizes WiFi-enabled SD cards.

As DSLR cameras have become a bigger part of the filmmaking landscape, I find it interesting that digital cinema filmmaking cameras are beginning to heavily adopt stills and frame grabs as a key feature. It’s telling that these two contrasting technologies are beginning to intersect.

But it makes sense. The ability to pull stills and frame grabs directly from a camera can be used for:

The only problem with frame grabs is the intrusion of retrieving them from the camera as camera operators, camera assistants, or DP’s work. Often, a DIT or AC will have to take over the camera for a few moments to generate the grabs and whisk them away on the SD card on which they’re stored.

Fortunately, for those who don’t like interruptions and those who don’t like interrupting, reader Jared Rogers has come up with an elegant solution that utilizes newer WiFi-enabled SD cards.

I’ll let Jared tell you in his own words how he recently used wifi-enabled SD cards to wirelessly deliver frame grabs from the camera to privileged crew on set:

Still frame grabs are becoming a common feature of new cameras — the Arri Alexa and Canon C300 to name two.

For the show I am currently in the middle of, these grabs are proving indispensable because of frequent lighting changes and the necessity to match shots from days or even weeks prior. Since the small image files are captured to an SD card, they are easily left in the camera for the duration of a project.

These can only be so useful, however, because in order to access the grabs one often needs to monopolize the camera, preventing the operator from continuing to frame the next shot.

Enter the new, under-publicized technology of WiFi-enabled SDHC cards. These handy little guys allow me to sift through, pull up and download screen grabs from the camera directly to my phone. Without a time-wasting hunt through the camera menus or, in the case of the C300, a complete reboot into “Media” mode.

Not all WiFi cards allow for this trick. After a couple failed attempts and heavy reliance on’s return policy, I found the Toshiba FlashAir 8GB is the best choice. It doesn’t require any proprietary app or software and allows comprehensive access to the file directories. To be more nerdy and specific, other brands only search for images within a DCIM root folder, which the Alexa doesn’t have. These other brands may work with the C300, as it uses said DCIM root for any images.

There are a few other technical limitations of my system that I am still working out; one being the necessity to partition an 8GB FlashAir for compatibility with the 4GB limit of the Alexa. Even so, I have been using this new system for the past few days and am on to something that will speed up our camera department workflow. At least for this job.

The main technical challenge with the Alexa is spoofing the firmware into thinking the card was formatted / prepared in the camera. This is pretty much as easy as cutting and pasting an Alexa SD card directory onto the WiFi card. But it left some quirks that I didn’t like, so next time I’ll try a traditional in-camera format, and then cut and paste theWiFi software onto the root afterwards.

It may also be that the speed of the Toshiba card can’t handle too many grabs at one time. In a few instances, the card only captured half an image, and each subsequent image was corrupted. This necessitated a trip to DIT and some simple disk repair. It was always during playback that this happened, and could probably be avoided with a little more patience; letting the camera finish the grab before exiting playback.

I think of screen grabs as gravy, so the slim chance of a corrupted still frame didn’t outweigh the advantage of WiFi. Some may disagree.

My only beef with the Toshiba card is that it doesn’t display thumbnails as you browse the shots on your phone.

The process is not perfect, but the potential is pretty cool. And having quick access to the grabs really saved our butts a couple times. I even had the director hovering around camera staring at his phone (more than normal) downloading the grabs. Not sure how the DP felt about that one :)

We got some great in-camera BTS shots too, usually when miscellaneous crew were asked to stand-in. The director was live-tweeting some shots to promote the show. The set dresser also found it a handy tool and an alternative to snapping shots of the 17″ monitor.

It may go without saying, but I was very careful who I gave the WiFi password, to prevent top-secret shots from being posted too soon.

He also followed up a few days later with this update, “Used the Toshiba card on a C300 shoot today. It works even better than on the Alexa. Thumbnails are available with an extremely fast download speed to my phone.”

The downside of Jared’s approach is finding a working pair of wireless SD card and camera. As he pointed out, there may be obstacles to get certain cameras to recognize and utilize the SD card’s wireless functionality. It’s also a possibility that they may not work together at all.

But the upside is a less intrusive way to access frame grabs, a faster workflow in processing them, and the ability to give multiple parties access to the same stills all at once.

And not only is Jared showing hypothetical situations in which they can be used, but real world examples of how they have been used: the director could reference them, the production designer used the grabs to log notes, and it made Jared’s work more efficient.

It’s a great, simple way to eliminate the added steps of using traditional SD card frame grabs

If you haven’t used the stills feature of a digital cinema camera before because you were worried about the back and forth of downloading, this may encourage you to take advantage of it. Imagine accessing frame grabs from the previous shot on an iPad for lighting references or blocking references — among other possibilities.

All of this is capable with normal SD cards, but using a wireless one streamlines the process and provides a certain level of convenience. This trick won’t make or break a production, but if you can get it working, it can provide real benefits.

Big thanks to Jared Rogers for e-mailing me his idea and allowing me to share it here. If you have questions for Jared, feel free to ask in the comments or send him a note via Twitter.

  • Mike Kubeisy

    So Jared your info was great, except you forgot to mention one very important thing. capturing BTS images and other stills is a major union violation, that’s for the Still Photographer to do and I know you don’t want to start that issue when on a union set.

    • Jared.c.Rogers

      Great point, Mike. Be very careful about who you give the WiFi password to. In my case I use the grabs to help the DP compose future shots (matching, etc.). ACs and DITs always have pretty much unchecked access to the footage, grabs, even a-camera BTS video. That comes with a lot of responsibility to make sure it doesn’t fall into the wrong hands.