Many of the reasons for Why do some professional cameras have dual memory card slots? seem to apply to consumer interchangeable lens cameras (whether mirrorless or SLRs) as well:

  • If one SD card becomes corrupt, I want to continue shooting to the other one.

  • I may want to shoot a burst faster than one card can handle.

  • I may have two small SD cards. Rather than buying a bigger one, or carrying both and swapping them, which is inconvenient, it would be good if the camera let me combine the capacity and speed of both cards.

An SD slot takes up a tiny fraction of the room in an interchangeable lens camera. Maybe the manufacturers want to artificially differentiate consumer cameras from pro models, but nobody looking for a $600 camera will buy a $3000 camera because the latter supports two SD cards.

  • When you go out to snap a few I can understand you don't carry an extra SD-card in your pocket, but why not take it with you when there's anything even half-serious photography in your mind? Jan 5, 2014 at 17:11
  • I do that, but I learnt this lesson the hard way, so I wanted to see if there's a better solution, so that everyone doesn't need to learn the hard way to carry another card. Thanks. Jan 5, 2014 at 17:37
  • It's a little bit about price, a little bit about size, a little bit about complexity (less is good for consumer items), and a bit more about artificial market differentiation - nobody looking for a $600 camera will buy a $3000 camera for dual slots, but manufacturers like to fill every market tier, so somebody looking for a $2500 camera might buy a $3000, and that's an easy $500 for the manufacturer.
    – Matt Grum
    Jan 6, 2014 at 9:53

5 Answers 5


It is not only about market demands, but also a market competition matter.

For example, up to until Pentax started making prosumer weather-sealed DSLRs no one bothered to make ones. Now every major maker to my knowledge have a weather-sealed mid-range DSLR. Just wait until someone does a dual card mid-range camera and you'll see what will happen after.

(Why else you would buy a Pro body?..)

  • You may be correct, but I tend to think a dual card compact mirrorless (which is what we are talking about here, not a mid range SLR) in the space occupied by cameras such as the NEX-5 would not be that attractive to buyers of those type cameras. Many are buying them primarily because of their compact size and another card slot works against that advantage.
    – Michael C
    Jan 6, 2014 at 7:27
  • Another SD card slot would occupy a negligible amount of space. Jan 6, 2014 at 10:18

The problem is that those reasons don't apply and if they did more consumers would be willing to pay out for better cameras with those features and the others that come with more expensive kit.

  • If an SD card becomes corrupt, an amateur has plenty of time to change cards and less need to guarantee capturing the action such as at an event. If an amateur misses the shot then all they lose is the shot - not a client who pays for your services.

  • The burst rate in lower end kit is usually limited by factors other than the SD card itself (such as the SD bus or processor output.)

  • Having more cards will not be of any benefit, the cost of extra kit and software to handle them is more than the (zero) cost of just switching cards yourself.

Ultimately you could make that kind of argument for every single feature of a top-end camera. Consumers go out in the rain, why aren't low end cameras better protected from the elements? etc.

  • 3
    You might have had to stop shooting, but your only loss was the shots you were missing while you changed cards. It's reliable vs less reliable, it's that extra features cost and if they were worth it to you, you'd have bought a model with those features. The all-in cost (engineering, parts & software) would probably add something like $50 a unit to the manufacturing, so it's reasonable to gauge around $80-$100 on the ticket price, and for that money people will choose cameras with other features first. Jan 5, 2014 at 15:04
  • 2
    The material cost is probably only in the order of cents, but the changes to the design and software are where the cost is. The iPhone is a good example... the bulk of the costs are not hardware, they're design issues - getting all that stuff into the space and that costs big-time. Jan 5, 2014 at 15:46
  • 1
    If you only have one SD card it doesn't matter how many slots your camera has, if your only SD card craps out you're SOL!
    – Michael C
    Jan 5, 2014 at 15:54
  • 1
    The R&D costs associated with a design change for the next iPhone model can be spread across the vast numbers of iPhones sold. Those numbers dwarf the number of units ANY consumer grade camera sells.
    – Michael C
    Jan 5, 2014 at 16:25
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    It has been done. If you want that level of reliability, then buy a pro grade camera with dual memory slots. The whole point is the only buyers who demand dual slots are the same pros who demand a lot of other features found only in the pro grade cameras.
    – Michael C
    Jan 5, 2014 at 16:50

The primary reason is that the market has not demanded it. For users in the consumer model range, it seems they prefer either the lower price allowed by a single card slot or other features for the same increase in price. It is relatively easy to swap one card for another when the photos you are taking are not 'mission critical'.

If one SD card becomes corrupt, I want to continue shooting to the other one.

Fine. Swap the card out and keep shooting. The vast majority of photographers using consumer equipment find this perfectly acceptable.

I may want to shoot a burst faster than one card can handle.

For most cameras in the consumer range, the bottleneck is the processor speed or the SD bus speed. Putting two slots in such a camera probably wouldn't increase the burst rate at all.

I may have two small SD cards. Rather than buying a bigger one, or carrying both and swapping them, which is inconvenient, it would be good if the camera let me combine the capacity and speed of both cards.

Most consumers would rather leave the price of the camera cheaper and then choose the size and speed SD card they need.

  • You're assuming that everyone carries an extra SD card with them all the time. Most people don't, but some of them, if they have a second SD card, may install it in the camera and leave it there, which is more convenient than carrying it outside the camera. I don't think two SD cards will increase the price much. The processor in an iPhone is estimated to cost $20. An SD card slot should be of the order of cents. Inconsequential in cameras costing hundreds of dollars. I do take your point about the processor speed or the bus speed being the bottleneck. Jan 5, 2014 at 16:39
  • 1
    If you only own one SD card, it matters not how many slots the camera has, does it?
    – Michael C
    Jan 5, 2014 at 16:41
  • You caught me in the middle of an edit. I wasn't clear originally. Please take a look now. Jan 5, 2014 at 16:42
  • 1
    The hardware cost of the iPhone processor is estimated to cost $20. The R&D, software, bug testing, etc. cost is higher. In the case of the iPhone, that design and engineering cost is spread over millions upon millions of sales units. No consumer grade camera model on the market sells remotely that many units, so the design and engineering cost per unit is a much larger part of the equation.
    – Michael C
    Jan 5, 2014 at 16:45
  • I agree with that. Jan 5, 2014 at 17:36

There's no doubt about the benefits of having dual memory cards, but I suspect that the added size and complexity of dual slots is understated. The Nikon D7x00 series has a card door that's the same size as those for CF cards, while the old dual-slot Sony SLRs had a space many times the thickness of the cards between them.

But what I want to answer is this: "Maybe the manufacturers want to artificially differentiate consumer cameras from pro models, but nobody looking for a $600 camera will buy a $3000 camera because the latter supports two SD cards."

Well… of course. Cameras are products designed to meet a certain price point, as are lenses, as are shoes, as are cars, as are computers, as are phones, as are chairs, as are watches. Nobody who buys a $300 Seiko Kenetic wristwatch will buy a $6000 Grand Seiko Spring Drive just for its continuously sweeping seconds hand, even though that's a definitive difference.

The good news is that the price difference between single and dual-card cameras needn't be all that great. In the current Nikon line the difference is about $400, and in exchange for that the camera gains a great number of far more significant photographic features. And when I show those cameras to shoppers in the store where I work it's typically those other features, not the dual SD card slots, that they ask about.

Perhaps as 4K video becomes more established dual card slots will be a feature that gains in popularity and migrates downwards in the price points. But SD card capacities continue to grow even as their prices shrink, and dual cards slots does directly conflict with the move to smaller cameras. Perhaps the future will be dual Micro SD cards – who knows?

  • Dual micro SD cards are an interesting idea. They'd address the argument some people are making about lack of space in cameras for two SD cards (not that I'm convinced that an SD card occupies a significant fraction of space in a camera, but that's a different discussion). Feb 28, 2014 at 17:07
  • Dual microSD to MS Pro Duo adapters exist ... now if one made them in standard SD form factor and added a RAID-1 facility.... Feb 20, 2019 at 19:41

The cost isn't as zero as it seems.

Good quality connectors (including card slots) are actually among the more expensive parts to put into an electronic product.

Compare eg https://uk.farnell.com/c/connectors/memory-sockets?connector-type=sd-card - a decent quality SD card socket will cost you a literal buck or two even when bought in bulk. And integrating a 2 buck part tends to require you to raise your sale price by much more than 2 bucks :)

Then, you need extra support electronics, and depending on the device construction, extra PCB/flexprint real estate (which is also relatively expensive).

Then, there is power budget to consider: The power consumption of an SD card being written to is far from zero - UHS-II, by specification, is allowed to draw almost 2 watts per card, which is enough to require consideration when designing the power supply circuitry for a camera....

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