When retina came out, Jobs said that you needed 300ppi at 12 inches. Soneira said it was 477ppi.
1 inch at 12 inches is 4.76 degrees, so Jobs is 63 pixels per degree. Soneira is 100 pixels per degree.
Assuming a 16:9 display:
If you are at 1.5m/60 inch from a 50 inch display, to meet Jobs's criteria you need 1455 lines -- so 4k (2160 lines). You need 2309 lines for Soneira's criteria. You get 40 degree coverage which is the upper bounds of THX.
If you are at 1.7m/66" from a 50" display, to meet Jobs's criteria you need 1326 lines -- so 4k (2160 lines). You need 2104 lines for Soneira's criteria. You get 36 degree coverage width wise which is the "perfect" bounds of THX.
If you are at 2m/80" from a 50" display, to meet Jobs's criteria you need 1098 lines -- so 1080p is fine. You need 1742 lines for Soneira. You get 30 degree coverage.
If you are at 3m/120" from a 50" display, to meet Jobs's criteria you need 735 lines -- so 1080p is fine. You need 1166 lines for Soneira, so you're only just out of that criteria. You get 20 degree coverage.
If you are 30cm/12" from a 7.4" display, you need 1083 lines (Jobs) and 1719 (Soneira), and get 30 degree coverage.
My own TV is c. 3m and 42", which I don't think is abnormally small from what people really have for living room TVs. That's 17 degrees, and needs 981 lines for Soneira's requirement, which 1080p does just fine.
If you have a large screen or sit very close to it (so 30 degrees), and are looking for a better-than-retina display, then sure, 4k is for you. For a home theatre where you're aiming for 36 degrees then certainly you'll want 4k
For the average person with an average tv though, I don't see the extra pixels of 4k being that important compared with a good viewing position, good lighting, good setup of the screen
Like the megapixel wars in cameras a decade ago, we're at the point where more pixels doesn't necessarily mean better. 4k, sure, it wouldn't be my prime consideration, but as almost all new TVs of living room size are 4k it's a given. I'd rather a 1080 TV with 6 HDMI inputs than a 4k TV with two inputs though.
I had the misfortune of watching the final season of game of thrones on some streaming platform from Sky (UK), at about 4 or 5mbit. It was awful, and that was nothing to do with the resolution.
I don't know who Soneira is and I trust NHK's research more than Jobs' marketing (especially since he seems to use the same flawed arcminute criteria), especially where TVs are concerned.
1 inch at 12 inches is 4.76 degrees, so Jobs is 63 pixels per degree. Soneira is 100 pixels per degree.
Assuming a 16:9 display:
If you are at 1.5m/60 inch from a 50 inch display, to meet Jobs's criteria you need 1455 lines -- so 4k (2160 lines). You need 2309 lines for Soneira's criteria. You get 40 degree coverage which is the upper bounds of THX.
If you are at 1.7m/66" from a 50" display, to meet Jobs's criteria you need 1326 lines -- so 4k (2160 lines). You need 2104 lines for Soneira's criteria. You get 36 degree coverage width wise which is the "perfect" bounds of THX.
If you are at 2m/80" from a 50" display, to meet Jobs's criteria you need 1098 lines -- so 1080p is fine. You need 1742 lines for Soneira. You get 30 degree coverage.
If you are at 3m/120" from a 50" display, to meet Jobs's criteria you need 735 lines -- so 1080p is fine. You need 1166 lines for Soneira, so you're only just out of that criteria. You get 20 degree coverage.
If you are 30cm/12" from a 7.4" display, you need 1083 lines (Jobs) and 1719 (Soneira), and get 30 degree coverage.
My own TV is c. 3m and 42", which I don't think is abnormally small from what people really have for living room TVs. That's 17 degrees, and needs 981 lines for Soneira's requirement, which 1080p does just fine.
If you have a large screen or sit very close to it (so 30 degrees), and are looking for a better-than-retina display, then sure, 4k is for you. For a home theatre where you're aiming for 36 degrees then certainly you'll want 4k
For the average person with an average tv though, I don't see the extra pixels of 4k being that important compared with a good viewing position, good lighting, good setup of the screen
Like the megapixel wars in cameras a decade ago, we're at the point where more pixels doesn't necessarily mean better. 4k, sure, it wouldn't be my prime consideration, but as almost all new TVs of living room size are 4k it's a given. I'd rather a 1080 TV with 6 HDMI inputs than a 4k TV with two inputs though.
I had the misfortune of watching the final season of game of thrones on some streaming platform from Sky (UK), at about 4 or 5mbit. It was awful, and that was nothing to do with the resolution.