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Minimum Screen Size For HD?


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In a recent review of 76cm widescreen sets in Choice magazine, the reviewer noted that although some of the sets tested were capable of displaying a HD image, at that screen size the difference in picture quality from SD wasn't really worth the extra expense. Is the reviewer right? If so what would be considered the minimum sceen size to benefit from HD?

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Hi Kev you have raised some interesting points which were discussed on this forum many months ago.I have gone from a 76cm HD CRT of which i could see a slight difference from HD to SD but not enough for my liking to justify the extra expense of the TV and HD STB,to an 86cm Super Fine Pitch Sony of which the difference from HD to SD is quite dramatic and very impressive.Although my 76cm was a Samsung HD ready model capable of displaying HD but not very well.Im sure that all of the guys who own quality 76cm HD CRTs ie Sony,Pana,Tosh etc will be able to tell you the difference they see between SD and HD on there sets.

The bigger the screen generally the bigger the difference.To answer your qestion IMO i would say 86cm as a minimum but thats just me.Also for the $$$ you can get some of theseHD CRTs now ie Pana 200A 86cm $3K its pretty good value.

Cheers Ryan

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It’s all about viewing distance.

If you view from 1.5 meters or less, a 76cm would be viable for HD use, but if you view from 3 meters, even an 86cm is really pushing it and a 106cm of larger set would be more appropriate.

For the eye to be able to resolve 1920x1080 resolution, you would need a 147cm or larger display for a 3 meter viewing distance.

Regards,

Owen

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an 86cm Super Fine Pitch Sony of which the difference from HD to SD is quite dramatic and very impressive.

The bigger the screen generally the bigger the difference.To answer your qestion IMO i would say 86cm as a minimum but thats just me.Also for the $$$ you can get some of theseHD CRTs now ie Pana 200A 86cm $3K its pretty good value.

Cheers Ryan

Thanks for the reply Ryan,

I've seen the Panasonic 86cm but haven't had the chance to have a good look at the PQ yet.

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It’s all about viewing distance.

If you view from 1.5 meters or less, a 76cm would be viable for HD use, but if you view from 3 meters, even an 86cm is really pushing it and a 106cm of larger set would be more appropriate.

For the eye to be able to resolve 1920x1080 resolution, you would need a 147cm or larger display for a 3 meter viewing distance.

Owen makes a great point which is very important re:viewing distance,my viewing distance is about 2m and with the 76cm Sammy the diff between SD and HD was bugger all but now with the Sony as i mentioned before its a big difference but obviously a much higher quality set,but as owen said 1.5m a 76cm will be fine so unless this was the case you would go an 86cm if you had a 2m viewing distance and so on as owen stated.

just to highjack this topic for one second,Owen how do you think i'd go with a 42" plasma with my viewing distance of 2m???Would i go cross eyed :blink: ???

Cheers Ryan

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It’s all about viewing distance.

If you view from 1.5 meters or less, a 76cm would be viable for HD use, but if you view from 3 meters, even an 86cm is really pushing it and a 106cm of larger set would be more appropriate.

For the eye to be able to resolve 1920x1080 resolution, you would need a 147cm or larger display for a 3 meter viewing distance.

Regards,

Owen

Hogwash!! (IMHO - and I'll explain why - read on only if you dare!).

Sorry Owen, but I used to judge photographic competitions and I can easily see differences from at least 6m on a 76cm set (but I do know what to look for, notwithstanding my ageing vision).

Anecdote 1: When recently comparing a 76cm CRT against a 106cm plasma, I deliberately stepped back about 6m from the Toshie and had HN arrange it so that the Viera was about 9m away, behind it, and slightly to the side. Then I could compare clarity, contrast and colour with both screens appearing to be about the same size to my eyes - and using only my central vision to skip from one to the other. (The only fair comparison).

However, what Owen says is entirely correct for a 'home theatre' experience - ie. not only being able to see the resolution difference but also getting into the widescreen cinema experience.

Anecdote 2: Sitting too close to a display can make you 'seasick' for general FTA viewing with all the crappy PQ they broadcast. Movies, however, benefit from the larger screen and/or a closer viewing distance to more closely resemble what we expect in a cinema (and how the director wanted us to see it!).

Folks who use an HD or SD PJ for movies and an HD CRT behind the fold-away PJ screen for general viewing have the best of both worlds, IMO!

2i cents,

Ian

[edit]

PS. In fact, our eyes are only sensitive to clarity in the very centre of our field of vision. Peripheral vision picks up the rest as a fuzzy blur!

However, our brains use some very clever tricks to interpolate this into an impression of sharp detail all around. Directors know this and try to keep the action/star in the centre of the frame - but TV execs know stuff-all about video/vision and try to fill as much of the screen as possible with detail they want us to see (ie. scrolling tickers, watermarks, panel guests, scores, promos, etc, etc.

You'll just end up with 'tennis neck' if you watch too much FTA garbage on too big a screen!!

[/edit]

Edited by ijd
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It’s all about viewing distance.

If you view from 1.5 meters or less, a 76cm would be viable for HD use, but if you view from 3 meters, even an 86cm is really pushing it and a 106cm of larger set would be more appropriate.

For the eye to be able to resolve 1920x1080 resolution, you would need a 147cm or larger display for a 3 meter viewing distance.

Regards,

Owen

Hogwash!! (IMHO - and I'll explain why - read on only if you dare!).

Sorry Owen, but I used to judge photographic competitions and I can easily see differences from at least 6m on a 76cm set (but I do know what to look for, notwithstanding my ageing vision).

Anecdote 1: When recently comparing a 76cm CRT against a 106cm plasma, I deliberately stepped back about 6m from the Toshie and had HN arrange it so that the Viera was about 9m away, behind it, and slightly to the side. Then I could compare clarity, contrast and colour with both screens appearing to be about the same size to my eyes - and using only my central vision to skip from one to the other. (The only fair comparison).

However, what Owen says is entirely correct for a 'home theatre' experience - ie. not only being able to see the resolution difference but also getting into the widescreen cinema experience.

Anecdote 2: Sitting too close to a display can make you 'seasick' for general FTA viewing with all the crappy PQ they broadcast. Movies, however, benefit from the larger screen and/or a closer viewing distance to more closely resemble what we expect in a cinema (and how the director wanted us to see it!).

Folks who use an HD or SD PJ for movies and an HD CRT behind the fold-away PJ screen for general viewing have the best of both worlds, IMO!

2i cents,

Ian

[edit]

PS. In fact, our eyes are only sensitive to clarity in the very centre of our field of vision. Peripheral vision picks up the rest as a fuzzy blur!

However, our brains use some very clever tricks to interpolate this into an impression of sharp detail all around. Directors know this and try to keep the action/star in the centre of the frame - but TV execs know stuff-all about video/vision and try to fill as much of the screen as possible with detail they want us to see (ie. scrolling tickers, watermarks, panel guests, scores, promos, etc, etc.

You'll just end up with 'tennis neck' if you watch too much FTA garbage on too big a screen!!

[/edit]

When I saw the "hogwash" I thought "Oh no! Here we go...", but, Ian's on the ball, pretty much (for a grumpy old ........) :P

NB: God, I'd hate to be a SalesDrone when you rock up, Ian! Talk about earning your commission! "Hey guys, how about you just knock down that wall so as I can get a real long view of the screen..." :blink:

When it comes to TV, some of the "facts" and "laws" of vision get a little blurry (scuse the pun).

While it is true to say that the eye can pick differences way beyond the capabilities of the current programming sources and display resolutions, given the source limitations, when viewing general tv/films the "size matters" rule does come into play sooner that one may expect.

The key to good HT is to get the viewing angle up to size.

But, to achieve a good (~30 degree) viewing angle, the definition has to be raised to high quality SD at the minimum, and preferably decent HD.

Carefully watching a small HD display from a distance, you can pick out that its HD versus SD, but you'd never watch tv/films like that.

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NB: God, I'd hate to be a SalesDrone when you rock up, Ian! Talk about earning your commission! "Hey guys, how about you just knock down that wall so as I can get a real long view of the screen..."

I don't recommend doing it from so far away! It was just the logistics of getting the two sets to appear the same size - when they wouldn't move a few other things (for some unexplained reason, they thought their counter needed to stay where it was), and search for some longer Monster cables to hook 'em both up.

For PQ comparisons, I would suggest about 3m for the 76cm and 4.2m for the 106cm. Might be easier if you pre-arrange an audition.

If they want 7 gorillas from me, they can put at least 30 minutes work into it!

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NB: God, I'd hate to be a SalesDrone when you rock up, Ian! Talk about earning your commission! "Hey guys, how about you just knock down that wall so as I can get a real long view of the screen..."

I don't recommend doing it from so far away! It was just the logistics of getting the two sets to appear the same size - when they wouldn't move a few other things (for some unexplained reason, they thought their counter needed to stay where it was), and search for some longer Monster cables to hook 'em both up.

For PQ comparisons, I would suggest about 3m for the 76cm and 4.2m for the 106cm. Might be easier if you pre-arrange an audition.

If they want 7 gorillas from me, they can put at least 30 minutes work into it!

Yep, 30 minutes a day/week/(however often types like us rock up) is not bad! :blink:

NB: You give them gorillas? Is that to replace the monkeys? :P

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Yep, 30 minutes a day/week/(however often types like us rock up) is not bad!  :blink:

I only do this when I'm serious about buying - and they already know this!

BTW, they will also order in a single set for me to compare against my favourite if I'm ready to jump. And to keep my cred, I only request it when I'm ready to jump.

Any store that won't do it, won't get my dollars! Simple!

Just ask Encel's! I wanted to buy a Loewe and some Polk speakers a couple of years ago but they were too lazy to even hook up the Polk sub! To quote Joel: "Trust me, it'll be GREAT!!" Yeah ....

There is another old post of mine about the exact same 'specialist' store (the only one I could find in Brisbane at the time that had both Toshiba sw9ua's for me to audition. They wouldn't even switch cables between two sets! Sheeeesh!

<end rant>

Hint: A gorilla is a large monkey.

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Yep, 30 minutes a day/week/(however often types like us rock up) is not bad!  :blink:

I only do this when I'm serious about buying - and they already know this!

BTW, they will also order in a single set for me to compare against my favourite if I'm ready to jump. And to keep my cred, I only request it when I'm ready to jump.

Any store that won't do it, won't get my dollars! Simple!

Just ask Encel's! I wanted to buy a Loewe and some Polk speakers a couple of years ago but they were too lazy to even hook up the Polk sub! To quote Joel: "Trust me, it'll be GREAT!!" Yeah ....

There is another old post of mine about the exact same 'specialist' store (the only one I could find in Brisbane at the time that had both Toshiba sw9ua's for me to audition. They wouldn't even switch cables between two sets! Sheeeesh!

<end rant>

Hint: A gorilla is a large monkey.

I am familliar with gorillas! Maybe I should have just made some reference to "paying peanuts" :P

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This discussion has been done to death in previous threads and the guns are still smoking.

1. OK on my 37" plasma (with 1024x1024 display resolution)I can tell the difference between HD and SD sitting 2.5-3m away from the screen.

2. When looking to buy a crt TV earlier in the year I honestly could not tell the difference between the 76cm HR & HX versions of Sony's TVs(one's got a high pitch tube, one doesn't) while watching the side by side on the ch loop for 20min using identical HD receivers and setup at Sony central.

3. I'd feel like sitting in the front row of a movie theatre(with a crook neck) if I was sitting in front of 50" display at the 2m Recommended THX viewing distance (36 degree viewing angle) or even worse 1.8m (maximum viewing distance for HDTV - fully resolved)*

Make your own conclusions - I have.

*using the viewing distance calculator:

http://www.myhometheater.homestead.com/vie...ancemetric.html

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So guys in the real world when you go to the cinema where do you sit.....

1.In the front

2.In the middle

3.At the back [all 3 Q includes side seating]

most in my experience head towards the rear!

cheers laurie

ps I wonder if that calculator works for Imax.... :blink:

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Approx 2x the screen width is a nice distance if ones source is decent (and it does not have to be HD)

2x really does mean that many of small displays one seem very close indeed..... really i guess single viewer displays?

I sit at 3.8m with a 16:9 diagnal size of 220cm (86inch)

Too big? Nope :blink: PJ is only an X1 with pixel matix on 16:9 screen of 800 x 450. ZERO visable screendoor at said distance. Picture for HTPC with FFDShow is as good as any direct view i have seen with comparable decent source. Somehow PJ's (well DLP anyways... new LCD are better) are more forgiving that direct views but not at expense of PQ.

For comparisons sake tonight i watched SD captured version of Cold Case with FFDShow. PQ is better thany anthing i've seen at the cinema.

(i usually sit 2/3 back)

PQ on the PJ for said show is compariable on 17inch flat CRT monitor running 1280 x 1024 of say 40-50cm.

I did borrow a 42inch plasma for a little while (SD) and viewing at about 3.5m the picture was WORSE than the projector yet the its less than 1/4 the size of the PJ (in area that is).

oh just check that calcualtor thingy..... seems im pretty much "spot on" the recommendation :P what a guess................ really i just went till i stoped seen screen door and the allow 1/2 m or so tolarance

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Ian,

With the greatest respect, your evaluation of a 76cm CRT and a 106cm Plasma proved nothing other then that the two displays look very different.

Differences in clarity, contrast and colour have nothing at all to do with resolution.

The human eye is only just able to resolve 720x576 resolution on a 76cm at 3 meters, so any higher resolution is out of the question.

How you managed to evaluate resolution on a 76cm TV at 6 meters is a complete mystery to me.

I very much doubt that there is a human alive that can resolve even close to 720x576 resolution on a 76cm TV at 6 meters.

One of the problems of comparing SD to HD is that it is close to imposable to obtain a FULL quality and full resolution PAL 768x576 source. DVD and free to air TV both analogue and digital are never full PAL quality. The correct number of pixels (720x576) are in the data stream, but the full resolution is not, due to pre filtering and compression.

If you ever got to see FULL quality PAL 720x576 video displayed, you would be amazed at how good it really is.

One of the few ways to get full PAL quality is to downscale HD video with a high quality scaler.

Now, if we display this down scaled video on a good HD TV that can also natively display a standard PAL resolution without scaling internally as well as HD resolution, we can do a fare comparison of SD resolution compared to HD resolution.

When you do a comparison this way, you will find that the difference between SD and HD at a normal viewing distance is a LOT smaller then you would think.

Even this type of comparison can be difficult, and prone to error, as many HD TV’s do a very poor job of displaying SD.

You will often find that people with HD 76cm TV’s say that HD looks much better then SD on there TV at 3 meter viewing distance.

Well this is because there TV is doing a poor job of displaying SD and that the SD video source is not full PAL quality.

Its also not fare to compare a cheap 76cm SD TV with an expensive HD 76cm TV displaying HD and say that the difference in picture quality is due the superior resolution of HD over SD.

If the SD TV where of the same relative quality and cost as the HD model and both video sources where FULL SD and HD quality respectively, the difference at 3 meters would be minimal at best.

In the end, resolution is an overrated specification.

It’s not the resolution of the picture that maters, it’s how good it looks to you.

There are many HD displays that have poor picture quality and cannot justify there price.

Regards,

Owen

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Ryan,

Regarding the 42” Plasma being too big at 2 meters.

I owned a 43” 4:3 TV (same screen height as a 55” 16:9) for 4 years and viewed it from 2.5 meters.

I never considered it too big, in fact I found that it was way to small.

I now have a 57” HD screen, and view it from 2.8 meters. I don’t consider it to big as it provides the minimum 26deg viewing angle.

Foxtel digital and free to air TV looks ordinary but quite watch able.

Upscaled DVD’s are very impressive and good 1920x1080i HD is an absolute joy to behold.

The problem with Plasma’s is that they tend to look ordinary up close. You tend to notice the pixilation, solarization and motion artifacts inherent in many digital displays.

But with the use of a good scaler for SD and a top quality 42” HD Plasma, it should be possible to get a good result at 2 meters

Regards,

Owen

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So guys in the real world when you go to the cinema where do you sit.....

1.In the front

2.In the middle

3.At the back [all 3 Q includes side seating]

most in my experience head towards the rear!

cheers laurie

ps I wonder if that calculator works for Imax.... :blink:

I, like most people like to sit about two thirds of the way back from the screen at the cinema.

Viewing my 57" screen from 2.8 meters is like sitting in the back row at the cinema (26deg viewing angle), except that the quality of picture I get at home is better then any cinema I have been in.

You really need a much larger screen then most people think, although for close viewing distances, source and display quality are VERY important.

I have never suffered from tennis neck. :P

Regards,

Owen

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Hi Owen,

I did not intend to accidentally* re-open the "recommended home viewing distance" argument again, or the "HD v. SD program quality" debate again, or the "mine's better than yours" debates again - or indeed any other subjective purchasing criteria debates again - with my comments on "one of the objective auditioning criteria I personally use - and the reasons** why it is valid" to evaluate sets of different sizes in a retail store viewing only the 1920x1080 NineHD Loop! Nothing more ... nothing less!

While I certainly wished to challenge your under-estimation of human visual acuity, I was hoping not to offend you with the style of my challenge! I respect your knowledge and experience of analogue video immensely, and learned much of what I currently think I know about DTV from you.

Best regards,

Ian

* In any event, I should know better by now than to expect that certain members wouldn't only read between my lines rather than concentrate on my actual words!

** FWIW, photographic competitions [in years gone by] usually stipulated the exact size and style of print to be submitted so that a fair comparison of other criteria could be made. The same approach should be used when auditioning - make sure that extraneous factors (size, STB, interconnects, store lighting, etc, etc) do not affect what is actually being assessed - clarity, colour and contrast of the display device.

Other factors (mpeg processing flaws, flicker, jitter, geometry, etc) need to be tested with a variety of material, varied sources, much closer viewing distances than will be used at home, and extended viewing. Nuff said.

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Thats a bit of a turnaround from the "Hogwash" reply! :blink::P

As I said before, and I think we can all generally agree (somewhat!) that eye IS capable of detecting "very small" differences in controlled situations, and can also help us make "overall subjective" opinions.

In the "real world" (aka "the completely unreal world") of HT, the best display performance will be one that combines a broad viewing angle with sufficient resolution to give the impression of fluidity and reality (whilst not going overboard and giving you tennis neck, etc).

Personally, I'm (and have always been) a complete "nutter" when it comes to PQ/realism/perfectionism/etc, and thats why I generally use a selection from three high quality displays, depending on the content and situation. (And dont need, or want, the compromise of a plasma*).

PS: From the "I judged competitions" file, I suppose its only fair to point out that I have always had an interest in photography and human vision, and have studied optics at university level (as well as such subjects as computer vision at honours level). {BTW: To complete the "relevant line-up list", I've also studied electronics at Uni, as well as other topical stuff like honours-level digital image processing, etc} ... so I'm not always "speakin outa mah ****!"

_______________________________________________

*Lights blue touchpaper, and runs like hell!

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To clarify Ians comments yesterday

1 Gorilla = $1,000.00 7 Gorillas = $7,000.00

Furthermore

1 Monkey = $500.00

Grey Ghost $100.00 (now green no new nickname)

Banana $ 50.00

Lobster $ 20.00

Blue Swimmer $10.00

All got to do with currency.

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