The release of the Canon EOS R and Nikon Z6 and Z7 raised so much fuss regarding their lack of dual memory card slots that several photographers' heads exploded. It turns out that dual memory card slots are the most important issue for photographers. The issue certainly comes out ahead of the future of the industry, the death of photojournalism, and Uncle Ed with his smartphone who can shoot your wedding cheaper than those hucksters with the big heavy cameras.
Yes, the internet photography community has it right. It's the law that real cameras for professionals have to have dual memory card slots. No professional or aspiring professional would dare be caught fooling around with a camera that can only write to a single memory card.
This is true. Professional photographers are legally obligated to use cameras that have (at least) two memory card slots, both of which are legally required to save copies of the photos being taken. The U.S. Supreme Court ruled on this in 2017 when they unanimously sided with that guy on the DPReview forum who wouldn't be caught dead using an old-fashioned single-memory-card-slot camera. The case was Technology v Technique. Look it up. It's on the books.
As a Nikon user, I can attest to the real necessity of having two memory card slots. I shot with a lot of Nikon bodies prior to their bodies with two slots. It was the fifth circle of hell in the old days. I think I only completed one shoot in twenty where the single memory card in my camera didn't lose images. Oftentimes, I could tell that the memory card was losing images because there was a smell like burning plastic coming from the card. Other times, the memory card door on the camera would spontaneously flip open, and the card would eject itself, laughing at me as it hurtled toward the ground. What I wouldn't have given for a D70 with two card slots! So many lost photos, not to mention angry clients.
To this day, I'm not sure how I got through my school years with only one memory card slot. In the early days of digital photography, I was one of the first people to shoot digital photos for my high school yearbook. Well, I liked the speed and efficiency of putting my photos directly into the electronic page layout instead of marking crop lines on 3x5 prints with a grease pencil like Fred Flintstone. Don't get me started on the problems of film (see below)!
Anyway, I had to redo so many classroom scenes just to get a handful of shots that hadn't been mangled by the memory card gremlins. Let me tell you, everyone at the basketball games really gets upset when you ask them to redo that game-winning shot from half-court because the file got corrupted because there was only one memory card in the camera. It wasn't my fault. Cameras with two memory card slots simply didn't exist.
It was more of the same in college. Whether it was photojournalism or graphic design work, I barely scraped by with D's, thanks to not having two memory card slots. While the other students made do with film (which has its own problems) and paste-up, I just had to try to be on the cutting edge. I figured better days were ahead, and sure enough, students today get their photographic projects done before they're even assigned, thanks to having dual memory card slots in their cameras.
Today, I follow the law. When I'm shooting promotional photos and videos at work, all of my cameras have dual memory card slots and they're writing every 1 and 0 to both cards. Same goes for my personal photography. The last time I used an old camera with only one memory card slot (the new ones had dead batteries or something), I had to cover the label with electrical tape in case a cop saw what I was doing. And sure enough, only three out of the hundred-fifty photos I took were mostly free of glitches from the single memory card slot. That brochure was not the success it should have been.
Let me get started on film. Obviously, we ran into the same problems with film. There's only one frame being exposed at a time with film, so you have no opportunity to have the peace of mind backup that you get with two memory card slots. Some people would fool themselves by taking two shots, so they had two frames of film for that particular photo. Well, that sure was a false premise. For one, when the back of the camera inevitably popped open and the film canister fell out of the camera and landed on the ground and fell apart, it didn't matter how many "backup" frames you took. They all got ruined. Not to mention the fact that even with a fast motor drive, you sure ain't going to get a proper backup exposure of an action scene.
Back to reality. Of the eighteen digital cameras I've regularly used over the years, four of them have two memory card slots. If I have a second memory card in the camera, it's for overflow, not backup. I might set the camera to write JPEGs to the second card for quick offload to a client.
The number of times I've had memory card issues has been minimal. Two times stand out to me. Once, I touched a memory card and hit it with a static electricity zap. Corrupted files resulted. Solution: don't handle the card on thick carpet or during a lightning storm. Second, a flaky memory card reader wasn't downloading from the card correctly, and I had to download some files twice. Solution: get a different card reader.
The number of times I've lost photos because the single memory card in the camera fouled up? None. Knock on wood. You'd better figure that you're more likely to have problems with the camera itself than the memory card, so two slots or ten won't make any difference.
I've shot weddings, sporting events, news coverage, and promotional materials, not to mention the really important personal work, all without worrying about whether my camera had two memory card slots. There are better things to worry about, such as writing a ridiculous essay on a ridiculous topic.
