It's not quite as extreme as you say: Fujifilm's X-T3, Sony's A7III and Panaonic's GH5 for example all have two slots and they're definitely not the highest end pro systems, I'd say they're more like mid-range prosumer.

This is speculation but it may have been that back when you bought your $500 camera, a single CF card wasn't been able to hold many photos, so you could insert two cards and start filling the second when the first was full. It could also have been that CF was relatively unreliable.

Today, regular consumers can fit thousands of photos on a single SD card, which from a reputable brand will be pretty reliable (I've never had a Sandisk, Sony or Samsung SD card die on me while shooting). The only people who need extra reliability are professionals who lose a great deal of money in that 1 in 1000 case where an SD card dies.

> It's not quite as extreme as you say: Fujifilm's X-T3, Sony's A7III and Panaonic's GH5 for example all have two slots

And they're all $1200+ cameras (with no lenses). That's a substantial price for a feature that has become cheaper to add over the years. An SD-Card bay is under $2, the plastic bespoke door that covers both bays likely costs more than adding the second bay would.

Strikes of artificial price segregation, the whole "prosumer" tier didn't even exist back in the mid to early 2000s.

> The only people who need extra reliability are professionals who lose a great deal of money in that 1 in 1000 case where an SD card dies.

Almost all photos are once in a lifetime. That wedding, birth, or even vacation likely won't happen again (and if it did it would be different anyway). Arguing that nobody "needs" reliability until profits are on the line isn't a particularly compelling argument in my opinion.

> An SD-Card bay is under $2, the plastic bespoke door that covers both bays likely costs more than adding the second bay would.

I think you're underestimating the cost quite a lot. It's not just a piece of plastic and a few bits of wire, you also need a high performance I/O controller to go with it. Assuming SD card readers aren't massively overpriced, you're looking at closer to $5-$10.

Then there's the space considerations. If you've seen a teardown of a modern camera, especially mirrorless, you've seen that they're quite densely packed. It's not necessarily trivial to find the space for an SD card slot.

I agree that if it were essentially free that more cameras should have them but I'm not so sure that it's as trivial to add them as you make it out to be.

> Arguing that nobody "needs" reliability until profits are on the line isn't a particularly compelling argument in my opinion.

My argument isn't so much that nobody "needs" reliability as due to modern reliability, few people would use it if they had it. It's very rare to hear about a dying SD card so it's not something an average person considers when buying a camera. Even if cameras had dual slots, I doubt your average family going on vacation to Disney would think to buy a second SD card for it.

Since few people want it and there is a cost for it, it makes sense to get rid of it.

All flash media cards should be treated as unreliable (source: 10 years photographing professionally). An errant static discharge, a damaged pin, or a cracked piece of thin plastic are all that stand between an easy offload of photos and possibly losing them completely. I _always_ configured the cameras to mirror to both card slots in order to have an instant backup, placing a larger capacity SD card in its slot and using smaller CF cards as the primary and swapping in and out. In my experience, CF cards are more durable due to being thicker, so I was more comfortable swapping those in and out regularly.

Let's not forget camera running out of juice or switching to the second battery mid-way through the write operation.

[happened to me on day two of a three-day destination wedding... ahh, my stomach still remembers my reaction when I see "Err" on camera... :O]

Yup, my X-T2 has dual slots and I absolutely make sure I write to 2 cards. I've never actually lost photos but it's absolutely something i want to guard against.

I used to do that but I haven’t had a single card failure in more than five years as long as I was using SanDisk cards. But I generally try to copy data off the card daily.

Yeah, when I travel I try to offload to the computer nightly, and sync to The Cloud or my house or whatever, overnight.

As consumer product quality increases, market segmentation needs to find different features to charge professional customers more.

agreed

“prosumer cameras” are weather sealed and fast and have high clean ISO for low light performance

And all around light years ahead of “high end professional” gear from not even 10 years ago

Its just arbitrary gatekeeping

Use what achieves your use case.

What camera was that?

I was very happy when the Canon 5D Mark III (released 2012) added a 2nd memory card slot, even though it was "only" SD (much slower at the time), because I could shoot to two cards once. And that was $3500!