Hi

Need some advice on buying a tv. I want to buy a 32" Sony widescreen tv. I have always been told to go for 100hz as the picture is far better. Now looking into the subject more this does not seem the case. Fast moving images on screen can leave a trail behind as the tv fails to boost the signal to 100hz quick enough.
TV signals are transmitted at 50hz so this should really be enough.

What are your views?
Have you had any experiences?

Cheers

[phelings]

You are right.50 hz gives natural pictures,100hz has faults such as the one you describe.But some people prefer each one-get a side by side demo in a non Comet shop and see if you can put up with,or even notice plastic faces and blurred movement.

[Radiohead]

Alternatively, 50Hz sets flicker like hell.

A well-sorted 100Hz set with a decent source will give stunning pictures - I've been using one for 4 years now and have never noticed "plastic faces".

You pays your money.....

The 50Hz vs. 100Hz debate is pretty much subjective.

For my eyes, I prefer 50Hz from aerial source and 100Hz from dvd source. But that's just me.

Also, depends what your budget is.

I considered what Sony 32 inch to get for about 4 months.

Eventually settled on a KD32DX40 as it has an internal "digibox" and I got JL to pricematch £669 from techtronics.

[bowler]

Are there any TVs that can switch between 100hz and 50hz?

[gbmitie]

yes

there is a good sony that does but I can't recall the model. Do a search.


gb--

[Radiohead]

Isn't it the DRC-MF models (eg KV32FQ80)....DRC100 and DCR50 modes.

[LV426]

This issue/question is entirely down to your own visual acuity (and that of others in your family etc that will also be viewing).

If you are susceptible to refresh rate flicker, then a 50hz TV is tiring on the eyes. The larger the screen, the worse it is.

There isn't a power on this earth that will make someone with 'slow' eyes understand how uncomfortable 50hz flicker can be.

So, if you are 'blessed' with 'fast' eyes, then regardless of any processing artefacts that may be introduced, you will need a 100hz TV to remain comfortable. And, if you have 'slow' eyes, you don't need one.

So, responses to a question like this will contradict.....people with 'slow' eyes will tell you that there is no problem with 50hz TVs and 100hz ones are poor. And others, like me, may tell you that 100hz is essential for comfortable viewing, rrgardless of the other effects.

However, I have to say that it MUST be your choice.

(BTW - there is another thread in here about reducing flicker on Panasonic Plasmas; the length of that thread, and the number of readers, might give you some indication of the extent to which people have 'discovered' flicker.....)

Hi

Thanks everyone for your advice. I guess i'll have to check it out myself. I have a couple of months before i move in to my house so i have the time.

Matt

[TVhomejs]

Hello

I bravely reopens an old discussion!

For about half a year I've looked at hundreds of 100 Hz TV's - and 50 Hz - and I've not yet found one single 100 Hz TV with details in picture which came really close to my 12 year old 50 Hz Finlux TV (or other good 50 Hz TV's I've watched with friends and family). I've watched Philips Pixel-Plus, JVC D.I.S.T., Loewe, B&O, Grundig, Sony (not yet FQ85 or HQ100 of course), Panasonic (not yet with Acuity) and many other brands. At home I've compared the picture from Philips 8807 and Panasonic PS10 with the picture from my Finlux and it was almost frightening how much more details my old TV had. Also watching DVD (via RGB). And I'm not even talking about the artifacts, which were many, especially on the Philips TV. In one big store I played around with all sorts of settings for Philips and Panasonic TV's. Pixel Plus TV's had a flickerfree picture with sharp contours and sharp text, but surprisingly less details and a clearly more artificial picture than the 8807. In the about 20 stores I've visited again and again one or more 50 Hz TV's would stand out with a natural picture and lots of details (in spite of bad terrestrial conditions).

So why not buy one? At first because I could not take in the reality! I had read all these fine reviews and did not trust my eyes. Surely the picture and the tubes must have gone better in 12 years! If I had handed on my Finlux to my brother at once, which was originally the plan, I've perhaps been stuck with a 100 Hz TV today, still struggling with the unpleasant truth, but having the Finlux as a reference, I could not lye to myself. The 100 Hz technology in the end results in a trade-off: Flickerfreeness for loss of details. And the struggle for solving the problems with natural motion seems to worsen that end-result. This is not about taste, habit or delusion. Then watching and discussing details in for example landscapes and photos with other people in my daily life, what I see is what other people tell me they see in 99 out of 100 observations. Of course I exclude people with poor eyesight with or without glasses!

The reason I still haven't bought a 50 Hz is: Very few features. Few zoom-options, few text-pages in memory, no PIP or PAT and so on. The manufacturers regrettably won't recognize that 100 Hz CRT TV's (digital-TV excluded?) is a failure. Every new top-model promises the final solution and the prizes go sky-high. Will it never end?

Who can explain to me what in the 100 Hz technology causes the loss of details? And why so many so easily accept artificial "enhancements" in picture-processing that violate the intensions that film-makers had when shooting scenes for cinema? Why should details in "dark areas" be revealed by "dynamic contrast" if it was never intended?
Why should "focus areas" benefit from additional detailing if not intended so by film-maker? And so on.

[cosaw]

TVhomejs, I hear where you're coming from, especilly your last paragraph.

Who can explain to me what in the 100 Hz technology causes the loss of details?

Remember, you still only start with 50 interlaced fields, this has to be interpolated up to 100. I think it's all about interlacing.

It's because of the interpolating of interlaced frames, it's difficult to do correctly. If the frames were progressive then interpolating from 50Hz to 100Hz would be easier but unnecesary as progressive frames can just be repeated.

I had the same lack of understanding of how this all worked and what created the problem but was recently enlightened by the 13th post (also see the previous 3) on the second page of this thread:
http://www.avforums.com/frame.html?h...threadid=91037

Have a look see, it was certainly a breakthrough for me. What we need is progressive sources and progressive scan then we can run them at whatever refresh rate we want (theoretically).

cosaw

[Demon]

Its not as simple as mentioned in that thread... There are so many other factors that it is hard to give one generic reason that 100Hz is different to 50Hz...

As an example.

1. 50Hz sets are more purely analogue, i.e. they generally have no processing done at all on the signal, obviously in a 12 year old set, there will be bugger all done to the signal, in the digital domain.. and this does filter the 'signal' which can reduce noise, etc. A good analogy is the 'valve' audio amps, these are highyl regarded by many audiophiles, as they give a 'warmer' sound, yet this is due to the non-linear characteristic of the valve, which technically is not as accurate as a full-on 'digital' amp.

2. 50Hz tubes phospors generally decay slower then 100Hz sets, this is since the 100Hz processing needs to render twice as many frames per second, and in order to 'reveal' this interframe information, the phosphors must be faster, or all this information would be lost. That is why, 100Hz sets that have a 50Hz mode generally look very very flcikery, and why most 50Hz sets look quite stable.. Of course, the norm these days is to have even faster phosphors decay rates, as the more processing they use, the more the interframe render is important to the overall output... and you are reliant on the interpolation.

WHat is clear is that 100Hz will not suit everyone, and one manufacturers 100Hz is not another manufacturers 100Hz, if you see what I mean...

I don't fully agree with the Progresive scan enables you to then run whatever refresh rate you require... its partly true, but you are still faced with the fact that incoming picture is still only contains 25fps (PAL)... and will need to still be interpolated to run at any other frequency.. in fact progressive scan ends up being only another software interpolation algorithm... the problem is there is only 25frames worth of real information in the signal and the only way to make this look like there is more information is to use some algorithm to generate the missing information, this could be progressive scan, or some other software algorithm, but the problem is that the algorithm will work positively in some scenarios, and worse in others....

THe debate will always rage, manufacturers are improving, we can see the impact the DCDi chipset has had, and even the new Toshiba range have a 'de-interlacing' (progressive scan like) algorithm, that is along the same lines..

You will still have people preferring their 50Hz set, or their 100Hz set.. its inevitable, look at the diversity in Hi-Fi..

Just my thoughts on the subject...

Who can explain to me what in the 100 Hz technology causes the loss of details? And why so many so easily accept artificial "enhancements" in picture-processing that violate the intensions that film-makers had when shooting scenes for cinema? Why should details in "dark areas" be revealed by "dynamic contrast" if it was never intended?

50Hz is not perfect I'm afraid, its a compromise between getting the phosphors to decay slow enough to reduce 'flicker' yet not too slow as to filter fast movement too much... the problem is too many people have the visual acuity to see the flicker.. so the choice is loose information due to excessive filtering (slow phosphor), or move to the digital domain and attempt to get a "better" compromise.. i.e. 100Hz...

I believe that only now, with the advent of the de-interlacing software algorithms, that we are getting a good compromise... given a good source, some 100Hz sets now give stunning pictures with little or no artefacts....

[cosaw]

Demon

As regards point 1, I know what you're talking about - I play guitar and have a "valvestate" marshall amp. It doesn't have valves but trys to emulate a valve sound, its a cheaper alternative! However I'm not sure if or how you are drawing a distinction between 50Hz analogue sets and 50Hz digital sets (which would receive video compressed with some sort of mpeg algorithm). It's then a case of snow vs mpeg artifacts, both of which if you interpolate up to 100 Hz will lead to even more of the respective type of noise in the picture.

I don't fully agree with the Progresive scan enables you to then run whatever refresh rate you require

etc.

Perhaps I should have made myself a little clearer. I don't wish to apply a progressive algorithm to an interlaced source, as you point out that still creates problems. I was being more ambitious: I want a progresive source: 24/25 progressive frames. It is then a more simple case of factoring up the refresh rate. eg I watch region 2 dvds on my pc at 25fps x 3 = 75Hz. However there is much debate over whether dvd is encoded progressive or interlaced, but thats another story.

I live in hope for fully progressive broadcasts etc. When hell freezes over!

cosaw

[Demon]

Cosaw, I like your thinking.. I'll be at the front of the queue when we get anything like that!!!

[TVhomejs]

Hi again

My next answer won't be that long!

Cosaw, Demon and others, please make allowances for my shortcomings in expressing myself in english! I'm real good at reading and understanding it though.

50Hz sets are more purely analogue, i.e. they generally have no processing done at all on the signal, obviously in a 12 year old set, there will be bugger all done to the signal, in the digital domain.. and this does filter the 'signal' which can reduce noise, etc. A good analogy is the 'valve' audio amps, these are highyl regarded by many audiophiles, as they give a 'warmer' sound, yet this is due to the non-linear characteristic of the valve, which technically is not as accurate as a full-on 'digital' amp.

Demon, I have to admit that the combination of interlacing and what you call "slow phosphors" (perhaps not originally intended) surely "filters" information available in the incoming signal and creates a relatively stable, pleasant picture with smooth movements. However I don't buy your analogy with "valve" audio amps as a whole. My observations are not about preferring "filtered", "warm" analogue signals, hiding the noise and rudeness of old 50Hz TV sets, but quite the opposite! These 50Hz sets appear to reveal a "lifelike" image, picture information like details in sceneries, grass, wood and faces plus the sort of depth, I can watch right now through my window, from different sources - analogue broadcasting, VCR or DVD - much better than high-priced 100Hz TV sets. Obviously much crucial picture information is "filtered out" on these! Crucial because this information is essential for the quality of experiencing movies, series, documentary, sitcoms, you name it, and I try to understand why this has happened and to find some hope that something can and will be done about it. Surely its about the digital processing that 100Hz tecnology makes necessary.

50Hz tubes phospors generally decay slower then 100Hz sets, this is since the 100Hz processing needs to render twice as many frames per second, and in order to 'reveal' this interframe information, the phosphors must be faster, or all this information would be lost. That is why, 100Hz sets that have a 50Hz mode generally look very very flcikery, and why most 50Hz sets look quite stable.. Of course, the norm these days is to have even faster phosphors decay rates, as the more processing they use, the more the interframe render is important to the overall output... and you are reliant on the interpolation.

Most of what you write here makes sense to me. But what it also tells me is that if we had stayed with the 50Hz (and perhaps smaller screens like my 25") there would be no need for all this digital processing and complex interpolation algorithms! Having seen many "generations" of 100Hz sets, what seems a common problem from the earlier ones to the latest (repeat: I've still not seen Panasonic "Acuity" with Quintrix SR, Sony FQ85 and HQ100 with "Super Fine Pitch", but I'm not a believer!) is the inability to cope both with interpolation and preserving fine details and lifelike depth inherent in the incoming 25fps interlaced signal. They are probably overmatched because it's hell of a job in itself for a tube to be "capable of a wide gray scale" and "to show images with very low luminance levels (shadow detail) as well as a very high luminance levels (highlights) in the same scene", as Peter H. Putman puts it in his fine article "Shades of Gray" (http://svconline.com/ar/avinstall_shades_gray/index.htm) in Sound & Video Contractor, Mar 1, 2003. He also states this: "The truth is gray scale is the single most important attribute of any electronic display. Without shades of gray, there isn't any contrast. Without shades of gray, you can't create wide color palettes. Gray scales are where it all begins where it all begins when a projector or monitor first comes to life on the drawing board." And on top of all this comes color without purity or registration problems, image focusing and geometry. I have observed a general inability for 100Hz TVs to show details in darker areas, but perhaps this is only an example of a broader inability to show many shades of gray?

50Hz is not perfect I'm afraid, its a compromise between getting the phosphors to decay slow enough to reduce 'flicker' yet not too slow as to filter fast movement too much... the problem is too many people have the visual acuity to see the flicker.. so the choice is loose information due to excessive filtering (slow phosphor), or move to the digital domain and attempt to get a "better" compromise.. i.e. 100Hz...

Not surprisingly, I don't agree with that statement.100Hz is not a "better" compromise. Given the widespread analogue 50Hz broadcast signal more picture information, vital for high quality experiences like the ones in cinema, is lost than gained. And though most people see the flicker (me too), they seem happy enough with the picture, when softened with some light in the living room. I agree, it isn't cinema, but it's a good compromise! When having to buy a new TV, most people I know (not upper middle class) go for a 50Hz 4:3 or 16:9 TV sets, 28" or 32", because thats what they come across when shopping in supermarkets.
But they (we) are shamefully let down, because it appears that the manufacturers have stopped the developement of these TV sets several years ago.You really don't get much more in this area than I got 12 years ago! Instead they put most of their money in 100Hz sets with poor results. Dealers desperately try to sell them by making glorious surround set ups (why are Philips Pixel Plus TVs so often showing cartoons?) and always, always placing 100Hz TVs on the floor, but 50Hz sets, dominating in numbers, above in 2 or more rows, further from the eye.

the problem is there is only 25frames worth of real information in the signal and the only way to make this look like there is more information is to use some algorithm to generate the missing information

Well, Demon, so it really comes down to having TV sets getting the most or best out of whatever incoming source signal, right? To me it means having access to visual (and audio) experiences that make my life richer. Mostly this again means having other peoples visual creations like movies, documentaries and football transmissions reproduced or simply produced on the screen as true to the makers' intensions as possible. If showing peoples faces with wrinkles, freckles and subtle expressions was intended and can be (re)produced from the incoming analogue or digital signal, using analogue or digital technology, or both, well, then you have to see it on the screen. Thats important, basic information, which must not be missing or lost in an effort to generate "look like more" spectacular, fancy images. From what I've seen, many 50Hz TV sets seem to manage this far better than most 100Hz sets.
I know, I know: High Definition TV! But is 100Hz really important then? USA and Japan seem to have bypassed that phase! Isn't it wiser "simply" to wish for, wait for and buy TV sets that can handle signals from widespread digital sources without being restrained to
a 100Hz frequency? In the meantime manufacturers could make profit by developing 50 Hz Tv sets without loss of information caused by excessive digital filtering! There might be smarter ways to get rid of flicker.

Cosaw, I can't really say much about the possible advantages of progressive scan or progressive sources. I need to study the subject and hopefully experience the technology in use. Perhaps you know some good links?

[Demon]

wow... long e-mail, I've scanned through it and think I get the point you are trying to make..

I think that if you look at the Tosh 36ZP38 and Panasonic 36PD30 (I know you haven't seen these yet), and had a chance to try them in your home, not with a poor source at a shop, you would see some of the best pictures available.

Ignore the fact they are 100Hz, the 'processing' is so good, especially on the Tosh, that pictures do indeed look amazingly natural, with expceptional detail. Just read the reviews as well!!

I have just finished setting up a 51WH36P ( a 100Hz CRT based rear projection from Toshiba that has the same platform as the 26ZP38) and can safely say that this is simply stunning. I have never seen detail like it.. and the naturalness of the picture is breathtaking, when setup correctly.. I would dare you not to be impressed. And all of this with a 'flicker free' stable image....

We all have our own criteria for what makes a 'good' picture , so please understand that to me, these new sets, especially the 51wh36, as I have set this up in situ, with a good source, is the best I have ever seen.. from any TV, 50 or 100 Hz...

[Stone Free]

There is a very good article which explains progressive scan, and contains details on why 100hz technology creates artifacts at http://www.hometheaterhifi.com/volum...e-10-2000.html

[bonzobanana]

I can see both sides but I have to say on a 28" widescreen I think 50hz is miles better. Certainly fine detail is one of the big casualties of 100hz sets as they digitise frames to create two images in the place of one and that process can lead to much lose of information and fine detail.

The analogy of valve amps would have the 100hz sets obviously as the valve amps as they have the most distorted images even if people prefer them compared to the original source. They are being distorted to reduce flicker but the distortion also creates new problems.

Getting 100hz right is one of the hardest things to do for a manufacturer and sets by Thomson and LG are basically to be avoided. Most JVC and Panasonic 100hz sets aren't great either. Theres obviously more to go wrong too and poorly setup sets are far more common with regard 100hz and progressive scan type sets.

[owenw]

This is an interesting discussion - I moved from an 12 year old Sony 25" TV to a Sony 100Hz 36" widescreen 2 years ago and while it's not perfect it can provide an excellent picture.

In my opinion:

Todays' TV's are substantially bigger than 10 years ago so you can see problems with the picture much more easily than you used to.

The image on TV's in shops look plastic because they put the contrast and brightness settings up way too much. I have my settings far lower than the defaults so the image is much more life-like and not straining on the eyes.

100Hz has it's limitations in fast moving sequences because the processor can't keep up and sometimes it is noticeable. Also things like fast rolling credits the football in soccer matches will leave a trail across the screen. Also the image quality drops like a stone and can get very noisy.
This is more apparent on the Sky Digital channels than DVD's, in my experience, possibly to do with the higher level of compression used on Sky channels.

These, IMO, are small niggles which the rock-solid flicker-free image makes up for.
Also the technology will improve as processing power increases.

However, I think we are reaching a point where standard definition TV is no longer good enough and HDTV is the way forward for a real improvement in picture quality. No amount of clever technology can make Standard definition look like High Def.

my 2 cents
Owen