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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173 Comments

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David Pavlich's picture

Another "they shot with only one roll of film" posts. They shot with one roll of film because that's all that was available. Why a person that is shooting a paying gig would do it without the added insurance that dual cards gives is beyond me. Why take the chance when you don't have to?

Nicolas KIEFFER's picture

Why in the film age it was not a problem, but now the photocamera that fullfill your needs have only one photo storage is a failure ?
Because other MILC cameras have dual slot ? So why even bothering about that one slot camera ? You are just doing a flawed choice and should really notice it does not fullfill all your needs !

Is it so difficult to read a datasheet and read 'one slot' ? If you cannot live with one slot cameras, just buy that 'two slot' camera and tadaaa ! No more need to whine nor cry anymore !

So what is the problem with Canon and Nikon new MILC ? Seriously ?

David Pavlich's picture

Do you think that during the film age that not one photo shoot was lost due to a problem with the film or developing? It was a problem, but it was the only choice at the time,

I do shoot with a two card camera because I like having that extra bit of insurance. If you don't need two slots, good for you, but don't bad mouth those of us that do not wish to take a chance of loosing a shoot because of a one card camera that had a card failure.

If you're accepting money for a shoot, you should provide the client with the best chance of receiving a professional outcome, especially for one off shoots like a wedding. A card failure may mean that you missed only 15 seconds of the wedding, but maybe that 15 seconds was the bride walking up the aisle.

I wouldn't want to have to tell the bride and groom that I missed a part of their wedding because I didn't provide equipment that would reduce the chances of a card failure compromising the outcome.

David, why go out into the street... you might die,

How many cards have you had fail on you in the last 15yrs..?

Matei Horvath's picture

I can also say you don't need a seatbelt! I'm an excellent driver! Never got into an accident. Guess what? It's not always about you. Hardware breaks. Period.

Steve Babb's picture

Wait, let me get this right, you are fanatical about shooting to dual cards because you're worried one card might fail in camera.
But you format the cards on an external computer and then put them straight into the camera to shoot? Okay......

Thomas Campbell's picture

No, I format them in camera before leaving for a photoshoot. I never format anything during a shoot. Sorry I was not clear enough on that.

Jacques Cornell's picture

Pretty much EVERY camera manufacturer makes it very clear that cards should be formatted IN THE CAMERA, not the computer.

Triggered let me include all the responses (excuses)

In 723 years of shooting professionally for millions of dollars I never had a single failure.

At least they used XQD, they fail less than SD despite having zero manufacturer numbers on failure rate, TBW or life expectancy.

Just shoot with 2 cameras. Never mind the fact that this doesn’t solve redundancy at all and is an illogical solution.

I don’t need 2 card slots. I’m also really great at apologizing.

Jeff McCollough's picture

723 years is a long time.

In 20 years of digital shooting I have never lost a single image because of a card failure. My second slot is set for overflow. Hope your handlers are paying you handsomely for being their lap-dog lackey/product shill.

Michael Jin's picture

Good for you. Plenty of others have.

David Pavlich's picture

Consider yourself fortunate. I had a card fail, but it was an SD card in my 5DIII and guess what....the CF card was also gathering the data. Nothing lost.

Andrew Richardson's picture

I’ve never been in a car accident while I was driving. I still wear a seatbelt though.

Mr Hogwallop's picture

In many states it;s the law...no laws yet for dual cards :)

Thomas Campbell's picture

Other than the Think Tank Pixel Pocket Rocket, I can't see anywhere I recommended anyone buy anything.

I am a terrible shill since I am not encouraging anyone to buy anything.

I would like to encourage Canon and Nikon to put in dual card slots in their next mirrorless camera, though.

Or, have single slot and permanent memory such as a cell phone does. I would actually love that.

I do not have any handlers and if I had received any compensation, I would be required to disclose it to you under FCC laws and FStoppers' rules.

Przemek Lodej's picture

I've been asking this for a while, why aren't camera manufacturers adding physical in camera SSD drives? Doesn't have to be large, 32 to 64GB. It's plenty. I use 32GB SD cards and it serves me well. On trips I use up two at the most at full resolution RAW. It boggles my mind why this hasn't been addressed yet.

Matei Horvath's picture

Are you shooting professionally, Nick? As that is quite a record. You are one lucky guy.

As one great man said...

Motti Bembaron's picture

Bang on. I had three failures in the past two years (Lexar) and in each time I had a backup card. In two instances the files could not be retrieved. The card that failed and could be retrieved is now used on my computer as a transfer card. It will never go into my camera.

Not having a second card is a dumb decision out of Nikon and Canon. They need to employ photographers along side their engineers when designing cameras.

michael buehrle's picture

i bet robert capa wished he had a competent darkroom asst, not a second card slot.

Michael Jin's picture

If Robert Capa was shooting digitally, a darkroom assistant would have been unnecessary so I'm not sure what your comment is supposed to imply.

michael buehrle's picture

ummmm, no. it was meant to imply that his asst screwed up his stuff.

Michael Jin's picture

So where does that enter into the discussion? Or is it just a random thing that you decided to throw in for humor?

michael buehrle's picture

because if he had not screwed up there would be 106 pics instead of 8. everyone is all crazy because a couple new cameras only have one slot, when it was common up until about 10 years ago to only have one slot. i doubt capa thought it was funny.

Michael Jin's picture

True. To be fair, the darkroom technician was under pressure from the paper to dry the negatives quickly for press.

David Pavlich's picture

Once again, it's all Capa had to shoot with. We have a choice today unlike they did back in the 'old days'.

Michael Holst's picture

Never shoot without a second photographer.....who also has two card slots!

Tony Northrup's picture

This is very standard practice for wedding photographers.

Michael Holst's picture

What about fashion, automotive, travel, architectural, medial, journalism, product, instagram, soccer mom?

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