Why don't consumer interchangeable-lens cameras support two SD cards?

Question

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.

Answer 1

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?..)

Answer 2

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.

Answer 3

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.

Answer 4

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?

Answer 5

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....