No, 2k is not dead, and for most viewers, can not be distinguished from 4k. That said, TV networks and internet distributors such as Netflix, increasingly prefer or require a 4k original. It's more marketing than anything else, but it's something to keep in mind if shooting for these markets. Cinemas are happy with 2k.
To think about though: We're shooting movies at 24fps. That's 1/48th second exposure for each frame. If you take any movie and view it frame by frame, from my experience, you're likely to see one really sharp frame every 12-36 frames. Most frames are full of motion blur as cameras and subjects are moving! And even when the motion stops for a moment, the chances of PERFECT focus are small. Close enough, most of the time. But perfect? Not so much. The style for most movies is fairly shallow DOF, and this makes sense. I shoot the bulk of my projects between f2.0 and 3.5. Mostly about f2.5.
It's only on a static camera, with a static subject, that one can even SEE the difference between 2k and 4k. And even then, you must be pretty close to the screen. Certainly closer than 95% of the people in a cinema will choose to sit.
Ironically, 4k display does help always in one respect. When you sit close, you won't notice the pixel grid. Even if the image itself is not more detailed.
There is one exception to my observations. 4K shot at 60fps and displayed at 60fps will look more detailed. (much less motion blur) When you see the "demo" at the TV store, this is what you're seeing. People also complain, "it looks like TV, and not a movie". No winning this one!
To keep-up with this conversation,
there are IMO some practical problems with 4K.
-as for cinema, the other day I saw a private projection and impressed by the organic look and overall quality of the footage, I asked "filmed on what?"..."Digital Bolex".
I search for this camera specs and it was Super16 CCD, cinema DNG, 12bits 444, 2048x1080. As we see, quite outdated compared to the curent mantra. No super35, no 4K, However it looked great.
- Then, in post, it's not really that 4k and beyond complicates, but becomes far more expensive. I can live with the need to keep upgraded the workstations for any pixel race past and future; but the big thing are datas. With 4K already, the amount of datas we have to deal with can not be ignored and require investement to make the all package works smoothly as it should. The step between HD /2k and 4K is not double nor comparable to still photography but exponential. That is a true concern.
When I see what a 2K small sensor Digital Bolex is still capable of, I have little doubt what I'd choose today in terms of usable/balanced system. Now gear vendors are putting the bar up to 8K already...
- Then, as for internet stream. 4K works at the condition that 1) you live in the center of a big city, 2) You have the best company and pay the price for the best internet connection possible. In Madrid I have both. But when you travel, that changes all. Not every european cities are equiped equaly with optic fiber high speed . I'm currently on the atlantic ocean and if you want to youtube videos in 4K, it's a complete pain. It simply does not load fast enough. So all the internet exploration I'm doing here is HD.
- What about stream? Remember "Alonso runs Indy"? I watched the Live stream from Verizon while in Madrid with a super fast connection. However, the guys at Indianapolis where overloaded and not even in HD it would play smooth because 4.000000 people decided to watch the live coverage at the same time. Imagine a similar scenario in 4k.