In the last 10 years there have been a number of significant innovations made to cameras and other photographic accessories. Some of these come about because the company making them takes a gamble that pays off, but more often than not it just doesn't. There've been plenty of attempts by brands to 'think different' or just on technological bandwagons, and some just don't catch on, even if they function perfectly well.
To be clear, in order for me to qualify something as a failure, a feature or product line needs to have been abandoned by its maker due to a lack of market or critical success. It also has to have had the potential to start a major trend in the industry that for one reason or another never caught on, so one-off goofball cameras are out of the running (sorry, Powershot N).
Pentax's token attempt at a large-sensor mirrorless camera was an interesting one to say the least, and it could easily be said that they took the term 'mirrorless' a bit too literally. The K-01 boiled down to being one of their entry-level bodies with the mirror and viewfinder prism removed. The big 'to-do' made by Pentax about it was its compatibility with their existing K-series lenses (including a new super-pancake 40mm), and its design by Marc Newson. If you just asked yourself 'Who?', you weren't the only one to ask that at the time.
What on paper looked like a best of both worlds ended up being the worst of each - the relative bulk of a DSLR combined with the sluggish performance of mirrorless bodies of the era. Consumers apparently saw it that way as well, since within a few months of its release it was quietly discontinued and had its price slashed in half to $350. At least the K-01 is a perfect was to explain to someone the difference flange distance makes to body size when they complain about not being to use existing lenses with a new mirrorless body.
Lytro Light Field Camera
Introduced as something that could revolutionize digital photography by allowing users to manipulate focus after the shot, the Lytro light field camera had huge potential, and generated a significant amount of buzz after it was first announced.
What could have been a huge success ended up being an interesting but gimmicky tech-demo wrapped up in rectangular prism that was less than ergonomically sound. Add to that a screen resolution lower than some watches, and an image size of only 1.2mp and you have a camera that's little more than a one-trick pony.
While the application of the technology was bungled, the tech itself still holds a possible future, but I doubt Lytro-branded cameras will be part of it. If the technology were to be licensed to allow it for use in a wider range of cameras, or if a larger camera company bought Lytro, things very well may be different down the road.
Edit: just so happens that a new model of this was announced while I was writing this article. Go figure.
XQD Memory Cards
When I first got into photography in 2003, there were no fewer than seven types of camera memory cards on the market: CF, Microdrive, SD, MMC, Smartmedia, xD, Memory Stick. It was like a wild west of memory, with various manufacturers all trying for a big land-grab in a new frontier. But as the dust settled by the start of the new decade, only CF and SD (and its children) remained.
Struggling for differentiation in a now-matured market, manufacturers got into a read/write speed arms race of sorts, releasing new cards that pushed the limits of the technology, even though most cameras couldn't keep up with write speeds. It was essentially muscle flexing by the card makers, as cards of the extreme speeds they released were only of use to an extremely small (but high-margin) segment of the market.
To go after this segment, a new standard was created called XQD, which far surpassed the performance of CF and SD cards...but at a price premium. The result was a fast card that never really caught on, mainly because only Sony and Nikon ever supported the format. Even then, the only DSLR to make use of them was the Nikon D4(s). The total lifespan of the format, from first announcement to word of its discontinuation was less than three years.
Since XQD doesn't officially stand for anything, I'll just assume it's short for Xtra Quick Demise.
This one just barely makes it in the countdown. mainly because its 'sequel' Micro Four Thirds has become extremely successful, but the original Four Thirds system was a disaster from the start. The reasoning behind it was sound - without film, many of the old photographic standards were unnecessary or made obsolete by advances in digital imaging technology.
Unlike the other manufacturers, who all continued to use systems designed for use with their legacy film equipment, 4/3 was meant to be built ground-up for digital. By having a smaller sensor with a 2.0x FOVCF and a 4:3 aspect ration, they could make smaller, lighter cameras and lenses and pictures that would fit the monitors of the time without having to crop or stretch.
The problem is that for a significant loss of sensor size, there was an insignificant loss of body/lens size and weight. Couple that with the fact that 4/3 bodies were priced around the same as APS-C cometitors of the time, and you end up with something that just won't sway consumers.
Luckily most of these drawbacks were corrected in 2009 when the Micro Four Thirds system was introduced. As for why they stayed with the 4:3 aspect ratio at a time when most monitors were 16:10 or 16:9...that one's beyond me.
Sony's SLT line
Released by Sony in 2009 to help differentiate them from the big two in the interchangeable lens market, SLT technology was a departure from anything we'd seen in a digital camera before. They used a fixed translucent mirror instead of a swinging one, and an EVF instead of an optical viewfinder.This meant that many of the drawbacks of a traditional SLR were now moot - Framerates could be faster, exposure/white balance could be previewed in the viewfinder, AF could be maintained between frames and vibration was lower without a moving mirror.
Even in use, the line worked well. On the higher-end bodies it was fairly easy to forget you were looking through an EVF and not an OVF, plus autofocus was snappy in all of them. There were caveats, though. Chief among them being that the translucent mirror sent 30% of all incoming light to the autofocus sensor. For whatever reason, that figure seemed to turn off a lot of photographers despite 30% of the light only being equal to 1/3 stop. It means having to use ISO 250 instead of 200, which isn't a big deal at all.
But the recent merger of the NEX system and Alpha system pretty much signals a quiet end for the SLT cameras, with Sony now focusing on mirrorless cameras. It didn't help that on-sensor phase detection made the line completely obsolete.
Update May 1, 2014: Sony just announced their first new SLT in ages today. I can't seem to catch a break.