4k, technically 2160p, is a new resolution standard designed to digital cinema and computer graphics. It's advantage in the fact that it provides for a higher image definition quality, more detailed picture and offer better fast-action and larger projection surface visibility.
4k is named due to a 4,000 pixels accross horizontal resolution as compared to 1080p and 720p resolutions that have pixels counted along their veritcal resolutions. The new standard renders more than four times higher image definition than that of 1080p.
What's in a name? Why is 4K called 4K and not 2160p? Simple answer - marketing! Consumers love big numbers. Display resolutions have been named after their vertical pixel or 'line' count since time immemorial. For eg, SD TV was 640x480i - so 480 for older NTSC or 576i for PAL regions.
A 4K Tv is really a 2160p TV, much like an HDTV is a 1080p or 720p TV. However, the marketers won out over the TV engineers (as they typically do), and the term stuck. 8K therefore, is 4320p.
This format provides for no change in horizontal resolution, and change in aspect is made through the vertical resolution. For example 4096×2304 is a frame size with aspect 16:9 and 4096×3072 — 4:3. The digital video resolutions examples:
|Full Aperture 4k
||4096 x 3112
||3656 x 2664
|Digital Cinema 4k
||4096 x 1714
|Digital Cinema Aperture 4k
||3996 x 2160
YouTube has since enabled 4k, and more recently, 8K. Curiously, youtube refers to the resolutions in their real terms, with 8K being listed as 4320p. As touched on below, 8K TVs are evolving in Japan, however it is still in its infancy, but it has a great potential. It is quite possible that this format will be increasingly in demand by the new YouTube digital video data delivery services in near future.
What's in it for me, will I see any benefit?
Like a lot of other things in technology, the answer is 'it depends'. Viewing distance is critical to determining if you will have any appreciable gain out of buying a 4K set. Simply put, you are going to have to sit closer, a lot closer to your TV than currently. If you cannot do that, the only other way is to buy a bigger screen. Much bigger. A 65" 4K TV will need to have a viewing distance of 4.2' for your eyes to resolve *all* the detail. In other words, put a 65" 1080p HD and a 65" 4K screen from the same brand next to each other, both professionally calibrated with the same image, just different resolutions, and to the vast majority of 20/20 vision people sitting ten feet away, it will look nigh on identical. See the chart below:
Now, seeing as most North American households still sit at an average of 10ft from their screens, and in Europe it's typically 15-20ft, a 4K screen may not be for you. If you DO sit around ten feet from your screen, and/or your screen will be less than 65", our reccomendation is that spend the extra on a BIGGER screen, instead of going the 4K option. As you can see, looking at a TV mounted in the living area, accross from the kitchen a large open plan home, it can be easily 40-50 ft away. At that distance even a whopping 150" 4k screen wouldn't do it!
If your head is spinning with all these numbers, here's an analogy. Imagine yourself sitting on a nice white sandy beach on a sunny day. If you look down beside, you can probably count the grains of sand, see individual grains. Now, look at your feet. Some of you may still be able to see individual grains. Now look 10 feet away. If you can count grains of sand at this point, I will give you a medal. This, is basically how resolving pixel detail works. If you cant be close enough to make out the difference in grains of sand, or pixels, then the benefits are dubious.
This is not to say that 4K is a waste of time, not at all. If you have a dedicated theatre/cinema room, where light can be controlled to theatre like levels, and you can sit close enough, with actual 4k content on a professionally calibrated set, they do indeed look incredible.
Ultimately, 4K is what I like to call an 'electric windows' factor. One waits long enough, and it simply becomes standard, and virtually every car has electric windows now, even economy cars - one can't buy a car without electric windows! For me, that is the time to jump in and buy.
Here's what two industry names say on viewing distance:
"How close to the TV must I sit to appreciate 4K?
The short answer is that between 5 and 6 ft. is the ideal viewing distance for a 55” or 65” Sony 4K Ultra HD TV. However, on a 55“, you can now sit as close as 3.6 ft and enjoy a visibly smoother and more detailed picture (e.g you won’t see the individual pixels). On a 65“ TV, you can sit as close as 4.2 ft. to appreciate 4K."
"On a 50-inch 1080p HD display, most consumers can begin to distinguish individual pixels only when standing within six feet of the screen. Therefore if your viewing distance is 10 feet or greater, an Ultra HD 50-inch display will likely have little perceived benefit in terms of image clarity and sharpness."
What about 8k/4320p and beyond?
The ink is barely dry on 4K Tv brochures and talk of 8k development is well under way. LG, Samsung, Sony and Panasonic are already on the bandwagon. However, some have said that 4320p is at the limit of human vision perception. Not to be outdone, Samsung is looking to release 11k screens in the future.
The benefits of 4k and 8k are marginal at best. You have to sit unrealistically close to see the full detail and you need 4k source material. If you use a 4k display as a computer monitor to view high resolution source material, you could benefit. Other than that, save your cash and purchase 1080p instead - and get more screen size for less money.
My recommendation for achieving the best picture quality for the lowest price is to focus on contrast ratio (meter tested) and look for these features:
- Look for OLED instead of LED/LCD: the near infinite contrast ratio of OLED will offer a vastly superior quality image. A 1080p OLED TV will have an overall better picture than a 4k LED/LCD. OLED is more expensive, but the prices are starting to come down.
- Look for the HDR (High Dynamic Range) feature: HDR adds a much more perceivable picture quality improvement than does higher resolution. HDR increases the contrast ratio between the brightest and darkest regions of the screen, which is the most beneficial thing you can do for image quality. Keep in mind that HDR source material is required for this to work, but I expect this to be much more broadly available because it can be “backwards applied” to existing 1080p content. HDR in 'real life' is situations where you have to squint your eyes looking at the sea glinting on a clear bright summers day.
HDR more realistically reproduces those types of high brightness detail.
The rub is however, that HDR sets often if not always come 'bundled' with 4K resoloution anyway.
The Imaging Science Foundation and THX state that the most important aspects of picture quality are (in order): 1) contrast ratio, 2) color saturation, 3) color accuracy, 4) resolution. Resolution is 4th on the list, so look at other factors first.
(Some content courtesy of carltonbale.com)