Never Shoot Without Dual Card Slots

Never Shoot Without Dual Card Slots

In the past few weeks, Nikon and Canon have released their new mirrorless offerings, the Z7 and R, to much fanfare. Despite the great specs and form factor, I won't buy either for one simple reason: neither one has dual card slots. I never shoot anything without dual card slots, and neither should you.

When shooting for clients, shooting for myself, or just casually taking a few pictures of my kids, I always shoot with two camera card slots. I am fanatic about not losing any files, be it for clients or just myself. If it is worth shooting, it is worth protecting those files.

In the time between starting this article and finishing it, I had two photoshoots. In the second one, a compact flash card actually corrupted and was not recoverable. I tried several different software solutions, but all of them failed to recover the images on the card. 

Screenshot of Image Rescue Software for memory card recovery

Image Rescue was unable to recover my corrupted memory card

Even though that card corrupted during the shoot, I didn't lose a single file because I shot everything to two memory cards. I wouldn't have even tried to recover the files if I was not in the middle of writing this article because every image was safely on my other card. 

My clients pay me to deliver, and I sure couldn't ask them to redo a wedding because the kiss didn't save to my memory card correctly. 

Constant improvement by card manufacturers have led to fewer card failures, but they still happen. I'm not exactly smart enough to explain how flash cards work or what makes them fail, but I do know someone who is smart enough to understand them. Jeff Wischkaemper is a research professor in the Department of Electrical and Computer Engineering at Texas A&M University. Dr. Wischkaemper also happens to be a talented amateur photographer, so he understands the importance of memory cards to photographers.

"We used CF cards in an industrial product for over a decade. This was not a photographic application, but the primary function of the of the cards was to store files of similar size and composition to images. The CF cards were, without question, the weakest part of the system. Virtually all cards experienced some data corruption after years of use - many of them experienced complete corruption of the entire card, to the extent that no data could be read or written," Dr. Wischkaemper said.

I am all about minimizing risk and there are several ways you can do that. You can minimize risk by buying good memory cards from authorized retailers. I have less failures in my Lexars and Sandisks bought from an authorized retailer such as B&H than I have had with other brands bought in other places. I don't even want to know how many counterfeit memory cards I have used over the years because I didn't buy exclusively from authorized retailers. 

Another way you can minimize risk is changing out memory cards before they fail. As Dr. Wischkaemper said, eventually they all cards he used suffered some corruption or data loss. Replace the cards before they corrupt. Sell them or keep them as emergency backup. You can also do what I do and have a bowl of old cards on a shelf for no particular reason other than I might one day use that 1GIG 80x card from 2005.

In addition to both those ways, you should always shoot dual card slots. I only use new cards purchased from authorized retailers and I change them out regularly. But cards can still corrupt at any given moment, so every time I take a picture, it is written to card slot A and card slot B.

I choose to use raw to card A and JPEG card slot B for a couple reasons, but the main reason is when I shot Canon, I noticed that sometimes the raw file would corrupt when I was hitting the buffer, which was often on the horrible buffer and slow write speeds of the 5D Mark III. But while the raw file would be corrupted, the JPEG file on the other card slot would be unaffected and could be edited normally.

More likely than a card corruption problem, though, is human error. I've heard countless stories of camera bags being stolen, memory cards falling out of pockets, or photographers thinking they backed up the card, then shooting over it without getting all the files.

A lot of photographers suggest using smaller cards and changing them out more frequently. Delkin recently announced three new XQD cards and the smallest size was 64GB. At the time of writing this, B&H didn't offer any XQD memory cards smaller than the Sony 32GB. XQD is the only card format in the new Nikon Z7.

I actually think shooting with smaller cards and switching them out will make you more prone to lose images, because I think the more likely event is human error than card corruption. 

Large cards are all I use — large enough where I do not need to switch out cards during a shoot. I know cards aren't going to fall out of my camera and because I use two cards, I know that me losing my cards is much more likely than both cards being corrupted and unable to recover any files. My cards are only formatted at home, placed in my camera, and only come out when it is time to ingest. Never will I format a card during a shoot.

When you have formatted cards for years, it becomes a habit you can do without thinking and so if you never format during a shoot, you will never format the wrong card out of habit. After a shoot, my used primary cards go into a Think Tank Pixel Pocket Rocket and that stays tethered to me. My secondary cards stay in the cameras. If someone steals all my gear after a shoot, I still have the primary images.

I am really excited to see what my friends, colleagues, and sworn enemies do with these new Nikon and Canon mirrorless cameras. With the great EVF and cool new features, I think we are going to see a lot of great stuff that had not been done with DSLRs. But you won't see it from me. I won't take the risk. I may fall behind the times on this new technology but the risk of losing irreplaceable images for a client is going to be substantially lower.

For years, photographers shot single images on single frames of film. If you ruined the film by not properly rewinding it or in the development process, it was gone and there was nothing you could do. Luckily, times have changed and technology has advanced.

I'll bet you Robert Capa wishes he had a second copy of all the images he shot as he landed with Company E on Omaha Beach for the first wave of attacks on D-Day. Of 106 frames Capa took on D-Day, only 8 were salvaged after the darkroom assistant turned on too much heat while drying the film.

If I lost 94% of my clients files from a wedding or portrait shoot, I doubt they would be comforted much to know that Robert Capa's film was melted almost 75 years ago so no big deal. It happens, right? It doesn't have to happen. We have the technology to do better and our clients deserve better than for us to risk their files with one card slot when there is an option for two.

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Previous comments
Matei Horvath's picture

My rule of thumb. Any paid assignment.

Rifki Syahputra's picture

single card slot disgusts me..

Hans Rosemond's picture

I’m really not sure why people get so defensive about this. If you want to shoot with one card slot, go ahead. The author is saying that the option is available for a much safer workflow and it has become standard with most professionals. He’s given his reasons why it isn’t worth the risk. The end. It’s no different than wearing a seatbelt. 999 out of 1000 times you may never need one. But, it’s become standard equipment because it IS safer. It’s worth the risk to some. Not so for others. You do you. No judgement.

user-156929's picture

"I never shoot anything without dual card slots, and neither should you." Apparently, the author doesn't share your attitude.

Hans Rosemond's picture

There's a difference between having an opinion about what your best practice should be and judging you as a person/photographer/intellectual. Stating his opinion is the purpose of the article. That's not being judgmental. He's supposed to take a stance.

Michael Holst's picture

So then there shouldn't be anything wrong with someone expressing the equivalent of "OK buddy, calm down", to absolute statements like "NEVER shoot without a second card slot."

Hans Rosemond's picture

Oh absolutely. Expressing that you think someone is overreacting isn't insulting their character or being snarky. You know when someone is being nasty and when they aren't.

Michael Holst's picture

I don't see people as being overly defensive or insulting for the most part. From what I can account, people are just tired of the divisive one sided statements like "Never shoot without two card slots", "You should only be shooting mirrorless", "blah blah blah film sucks because digital is the future".... Only a Sith deals in absolutes....

user-156929's picture

Of course you're right but I HATE being told what to do! :-( Having said that, I haven't shot with less than two cards since, well... <thinking> Since that's been an option! :-)

Hans Rosemond's picture

haha...I've been known to have a stubborn streak or two myself.

Dan Howell's picture

Actually, the article is not referenced as 'opinion'. It is in fact tagged as 'education'. He uses an absolute (repeatedly) when it is in fact at odds with many models of cameras or digital backs which don't offer dual cards like Leaf/Phase digital backs. Is the author saying that professionals can't consider these cameras for professional work? C'mon.

Hans Rosemond's picture

Most people shooting high end phase/leaf digital backs are tethering and have no need for dual card slots. As for the education tag, I got nothing. It’s a tag. It’s obviously an opinion piece.

Matei Horvath's picture

It's very weird, this reaction from people. I don't get it either. Dual cards slots wouldn't have hurt a fly, yet the subject seem to piss off a lot of people. You don't have to use them if you don't want to

frank nazario's picture

I worked for over 4 years with a body with a single sd card... And NEVER had a corrupted card...2 SanDisk cards 32gigs ...never failed. Today I have a 2 card body and format it as overflow on the second... Still no problems.

The sad truth is we now know Sony is the only one who have managed to get it all right. And the did spend a few few years and versions to get there.

So either get a Sony or stick to pro level DSLR. For those using it pretty much should be less of a loss.

Sony please put some color on your focus points and lose the grey. Start listing to your customers and do some firmware updates.

I can't help thinking about those nice colored focus points the new Nikon have. Red and blue and easy to see. Or that f2 zoom lens from Canon. But no I stuck with Sony's dual slots.

Anyway Zeiss did it right. Shoot straight to a SSD disk, upload with WiFi straight to Adobe Cloud. Does not get much better then that. Sony users will have to wait for that. How could a lens company make a fixed lens camera? It's strange times in deed.

They didn’t as one slot is faster than another.

Yes that kind of sucks but for photography I find the fastest normal SD cards from Sony to write fast, it's ok.
I actually think it was much better to put a SSD disk in the camera, and option to backup straight from camera, like the new Zeiss camera. They should have put a sim card to, but WiFi is good.
That camera pretty much sums up how to build a camera these days.

Krzysztof Kurzaj's picture

You understand that if this SSD in Zeiss camera fails you have much more of a problem than corrupted SD card in any other camera which can be replaced in few seconds? I trust you also understand this camera does not have memory card slot confirmed thus it will not provide any option of physical storage redundancy?
It's amazing how people read some two day old news bit from Photokina about a mock up (sic) camera which is to be released next year and instantaneously proclaim it as the next best thing since sliced bread. Then fast forward a year from now (delays, supply shortage, etc.) and first reviews willstart surfacing trashing this camera for unreliable autofocus, messy interface and slow write speeds despite using SSD simply because processing engine is not catching up. On top of that you will find out the live wi-fi backup is slowing things even more and drains battery like crazy and editing with Lightroom in camera is just a torture using a 4.3" LCD while most smartphones these days offer +5" workspace. So much for the hype.

I think you got me wrong. My Sony cameras are the best thing since sliced bread. With dual slots:)

To me that Zeiss camera corresponds to my vision of how to build a camera today and I love the concept. I also think that Samsung did some interesting thing with there Android cameras.

Actually also I don't think that camera is a hype, it's more like a prototype that could influence future cameras - that's how I look at it:)

Tony Northrup's picture

Strange how choosing whether to backup data has become emotional for so many. If you don't want to backup, fine, but don't get mad because someone discusses their very real experiences with data loss.

Krzysztof Kurzaj's picture

Tony, discussing one's experience with data loss is certainly helpful and much welcomed. Making people feel like they are complete dilettantes because they don't take their data loss prevention to a neurotic level is not helpful. Ideally on top of those two memory card slots you will also need a storage space on your machine, a back up space on another machine physically located elsewhere (you know, in case you house goes on fire) and preferably another back up on a cloud server and all of those synchronized. Now let's be real for a second, how many people outside of commercial photography business (and that would be many) can afford and more importantly NEED this kind of setup?
There is no problem with author making a statement that two card slots are better than one. It's certainly true. The problem with this write up is how hard it tries to be pretentious.

Pretty obvious that the people getting emotional are the people like you and the author of this article, who just can't fathom shooting on a single card and insist that everyone else do the same. This is literally the most trivial of trivial things, yet we've been inundated with claims that the sky is falling because there's only one slot...

Much ado about nothing.

Krzysztof Kurzaj's picture

As I currently do not own any dual slotted camera I understand it is better for me to just stay home and miss all the shots I will never take instead of going out there with any of my cameras and risking to MAYBE miss some shots in an unlikely scenario when my memory card fails. Makes sense?
"When shooting for clients, shooting for myself, or just casually taking a few pictures of my kids, I always shoot with two camera card slots." Yeah, I totally understand the need for redundancy in commercial photography scenario but requirement of dual memory slots for casual photos of kids is in my opinion on a borderline of OCD.

Jonathan Brady's picture

Oh! We're offering (obviously unqualified) clinical diagnosis in the comments section now, huh? I guess the saying holds up... when you can't attack the message very well, attack the messenger!

Krzysztof Kurzaj's picture

Well, some people seem "obviously unqualified" to interpret other people's comments :)

JetCity Ninja's picture

"A lot of photographers suggest using smaller cards and changing them out more frequently... I actually think shooting with smaller cards and switching them out will make you more prone to lose images, because I think the more likely event is human error than card corruption. "

uh, wat?

constantly removing your cards increases risk of breakage, especially while they're NOT in the camera, be it loss, theft, breakage, wear, or static electricity.

the best solution is to replace the cards on a schedule, like every year or two, rather than waiting for them to fail before replacing them.

besides, anyone relying on memory cards is a moron. i have my laptop in my backpack and i tether directly to it while it's connected to my home server and a cloud storage service, so every time i press the shutter, i have 3 backups in near real time with 2 of them off-site and thus invulnerable to any adverse conditions and risk in my immediate area. NO ONE SHOULD EVER SHOOT WITHOUT A TETHER AND CLOUD STORAGE.

gabe s's picture

Have a link for a Tether Tools table that can be worn on the body while shooting a wedding?

Przemek Lodej's picture

Ridiculous. Sure I'm going to shoot tethered while hiking in the high Andes in Peru or the Himalayas...seriously.

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