If you view them in any shop display, there is a startling difference between them from about 15 to 20 feet away.

For a 40" Ultra HD it's about 4feet I think.*

Most of the general public sit about 8.5 feet from their TV, regardless of the size of the screen.


EDIT: It might even be closer for a 40" TV, maybe 3feet.

For most of the public there is no point getting a 4k TV

Better to get a good quality 1080 TV, or maybe a medium quality brand (Samsung say) and go for a bigger screen. 1080 on 50" at the typical viewing distance of 8.5ft looks great.

This is simply impossible for most people. I cannot speak for you, maybe you have exceptionally rare visual acuity.

With a 50" Full HD set with good HD broadcasts I can get closer than 5ft before noticing any deterioration in PQ and it just doesn't feel right having the settee anywhere near that close. (Monitors used for desktop computing are another matter IMO, I'm sitting less than 3 feet from a 27" UHD display right now.)

If I ever upgrade the TV it will be to get a much larger screen and hopefully a better picture in other respects in addition to resolution, eg improved black level, wider colour range etc.

Not on a 40 inch if they are both showing demo material, at 10 foot the difference is already fading away. Probably the 4K set was showing demo material and the HD one a poor quality broadcast. Demo material is made by carefully choosing scenes that don't show the sets short comings then mastering it using that TV instead of a broadcast monitor.

4k works as a sales technique because in a shop the customer is standing inches from the screen and seeing incredibly detailed video.

So I expect TVs to move in that direction, just as happened with Full HD. Eventually you won't be able to buy Full HD

This is the way I would tend to go. Having now moved my viewing position, to 15 feet away from my tv ( a 32 inch Sony Bravia) the drop in picture quality is noticeable given it had only`100hz processing rate to start with.

I've found Sony Bravia TV (big enough for the space it has to fit). also this 50 inch LG

The Samsung DVD player I have says it upscales to 1080 via the HDMI connection when a disc is played, and I watch TV via my Sky box.

It would only be if Sky go into 4k broadcasting that I would even think of getting a 4k TV ( watch any F1 race on Sky HD and compare it with the BBC broadcast of the same race in HD and the difference in picture quality is noticeable)

All I can say is that I'm absolutely astounded if nobody else can see a huge difference.

What from, 10-15 feet away? - you can't even see HD detail at that distance, never mind UHD detail.

Don't be fooled with refresh rate numbers - that 200hz number is achieved via processing and both panels are native 50/60hz. The more expensive panels tend to have a native 100/120hz panel.

Given normal visual acuity ... Which is one minute of arc

The answer is 3 H fir HD and 1.5 H for UHD 1

But we don't sit that close. See Katy noland's paper http://www.bbc.co.uk/rd/publications/whitepaper287

I'm totally baffled by what you're on about?.

Broadcast standards are 25 or 30 frames per second, higher 'refresh' rates are 'made up' in the video processing in the TV, creating extra frames in between the broadcast ones.

Panels themselves don't have any 'native rate' as it's not a scanned device.

I note that 17% of Katy's group had surround sound so I doubt they were representative of the general public. Interesting that research has been done on these matters nevertheless.

..... As the BBC has done in the past .....
See nick Tanton's 2004 work http://www.bbc.co.uk/rd/publications/whitepaper090
And the companion by drewery and salmon http://downloads.bbc.co.uk/rd/pubs/w...les/WHP092.pdf

On Katy's work
Because the group was self selecting you would tend to get those who were more technically "with it"

25 and 30 frames per second (fps) represents a progressive signal being broadcast (1080p etc). In the main that's not what a broadcast signal is because it requires too wide a bandwidth pipeline. Those 25 or 30 frames per second are split in to odd and even *scan line fields. This is our broadcast system; interlaced TV - 576i or 1080i. This halves the temporal bandwidth requirement. There are exceptions. 720p is a ratified broadcast standard, but not used much if at all. Also of course the BBC has been playing around with 1080p test transmissions, but these are not a mainstream format.

As for the flat panels, they do have a refresh rate. A display doesn't have to scan sequential lines of a picture to have a refresh rate. All flat panels image one entire video frame at a time.

In the case of broadcast TV those frames are delivered as two interlaced halves and recombined by the set to make a complete frame. Any panel in a TV will have a limit on how fast it can refresh in a second. The minimum refresh rate to avoid flicker for most people is 50Hz, but flicker tends to be noticed mostly on panels using phosphor or decaying light technology (plasma and OLED in the main). LCD has a different nature and sustains the image between refreshes. Still, the panel has to be refreshed and with a 25 fps image that image is refreshed twice per frame. Therefore the minimum refresh rate of a panel is 50Hz. It takes better drive electronics and quicker reacting pixels to support higher refresh rate. That's why there's a step in pricing between the 50/60Hz panels and those that support higher refresh rates.

So it is true to say that the panels have a 'native rate' even if the interpretation is applied differently compared to CRT-based displays.


* Referring to scan lines is of course a throwback to CRT days, but the terminology remains despite technology's shift to panels that image a whole field or frame at a time.

An interesting read, thanks for that.

Having had a look at the specs on some of the 4K TVs Currys have, even the SONY BRAVIA KD85X9505BBAEP Smart 3D 4k Ultra HD 85" LED TV has only a 3840 x 2160 screen resolution.

I was in a very big TV showroom today with at least 100 TVs on display. You can't tell the difference between a standard HD picture on 4K and non-4K TVs, but if anybody can't see a dramatic difference between a standard HD picture and proper 4K material from 15 feet away, then all I can say is save your money and buy a standard HD telly..

Google is your friend, try it sometime.

https://en.wikipedia.org/wiki/Ultra-...ion_television

That's correct, 3840x2160 is the consumer resolution for tv's.

Projectors (consumer) have the full 4k resolution (4096x2160) as used in cinemas.

That is the way I'll be going. The company I work for offer an 8% discount at Currys, on top of voucher deals that could knock another £100 off so I could get this SONY BRAVIA KDL43W809CBU Smart 3D 43" LED TV for around £360. The one in my living room is a 5 year old SonyKLD32EX403, which will replace the one I have in my bedroom.

It will only be when Sky sorts out broadcasting in 4k and launch their box would I even consider buying a UHD TV

Will any of the HDR UHD sets hit shops this year or is it 2016?

I'm almost ready to buy a new TV and saw some great sets at IFA but I am not sure they'll be ready for Christmas?

If you want a HDR UHD TV it's best to wait until the standard has been set as Dolby, Phillips and the UHD Alliance have different ideas as to what the standard should be at the moment.

http://www.techradar.com/news/televi...inment-1280990

With all this discussion about 40" 4K TV's, are we overlooking the fact that the Aldi advert clearly says it's 48"?

This is from September where the TV they had was a 40" 4K TV for £299.99

Last week they introduced the 48" 4K

(In practice it's UHD not 4K)