Behind the scenes at a three camera interview.
We decided to shoot a video project with multiple GH5s over the last two days. We also decide to shoot in 4K and to shoot 10 bit and 4:2:2. If you do that you'll quickly find that while the GH5 camera is a robust and stable platform it does demand fast memory cards in order to push through high density video signals. I'd been using UHS-1, class 10 cards with 95mbs write times but found out the hard way that once you go with big files your SD memory card speed has to upgrade with you...
Here's what I learned: You can get away with using slower cards in certain situations. If the camera doesn't move. If the talent doesn't move very much. If you don't shoot stopped way down (which vastly increases the detail in video files, increasing dynamic file size) and if you aren't recording with all the available camera bells and whistles on. If you are running next to a subject who is also running and you are shooting at f16 and you have image stabilization engaged. Your crappy UHS-1 card will sooner or later generate a camera screen message that says "Recording was cancelled due to slow card write..." Or something like that.
What other things stress the system? Well, how about automatic diffraction compensation? Better to just shy away from apertures smaller than f8 and to keep this control off. Same for corner shading compensation. Just click "no." Some of the bells and whistles slow the whole process because the internal processors have more to do but the biggest culprit is cards that just can't suck up data fast enough. And, since you paid for all those other features you might feel entitled to use them....
In that case it is incumbent on you to supply your previously deprived camera system with a kick-ass fast SD card. If you are planning to take advantage of everything the GH5s have to offer you might use in-camera, 400 mb/s, All-I files as the gold standard to shoot for as a performance target. To play on this playground you are going to need a card with the following attributes: It should be a UHS-II card. That means it will have a second row of gold electrical contacts just below the usual UHS-I contact configuration. The UHS-II cards are speedier at reading and writing (anyone want to explain the technical reasons? We've got room in the comments....). The card should have a V90 rating. This is, as far as I know, the top rating for current SD cards. Oh, and you'll need a write time about 3-4X faster than a really good "Extreme" UHS-I card. Ready, set, let's drop $100 per card for 64 Gigabytes.... Or $278 for a 128 GB card...
The $100 price tag is just about double the price of previous generation of 64 Gb cards which I purchased. So maybe memory isn't quite as cheap as the pundits proclaim....
But wait! There's more! Each GH5 comes with two card slots and unlike some of their less well spec'd brethren both of the slots are UHS-II ready. This means that if you are using two cards for simultaneous back-ups your camera can only write as fast as the slowest card can accommodate. This means that in practice you'll want/need to have a V90 UHS-II card in both slots. Now you have $200 per camera for basically the same 64 GB. Shooting three cameras deep and begging for simultaneous back-up? That's three cameras X $200 per camera or about $600 for a little over thirty minutes of 400 mb/s All-I shooting. That's $1200 per hour. More or less. Thank goodness the cards are re-usable.
We opted for a lower intensity codec on this project. One with an average throughput of 150 mb/s. But a faster card makes for a more responsive camera system whether you are shooting big video files or slamming through a bunch of raw photo files. The faster the card the better advantage you can take of a big, fast buffer. After all, you paid for it....
Even if you never shoot a lick of video a good UHS-II card with a fast rating will make your raw+jpeg shooting Texas Jackrabbit fast. Even as it puts your credit card on a hard diet...
I'm using a combination of Delkin 128 GB, V60 cards and two Hoodman 64 GB, V90 cards at the moment. I'm sure it's advertising bravado but Hoodman labels them as 2000X cards. 8K, ultraHD capable. Guess if I want to be a really serious pro I should buy another handful...
I'd buy the 128 GB cards but they're way too pricey...