Panasonic PZ70 v PZ700-why the difference in contrast Ratio?

Discussion in 'Panasonic TVs Forum' started by SATM, Sep 8, 2007.

  1. SATM

    SATM
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    I appreciate that a Manufacturer's quoted Contrast Ratio is generally a work of fiction,but is anyone able to explain the reason for the difference in CR between these two TVs?
    Is CR a function of the panel,or of the processing?
    If the former,why should Panasonic be using two different full HD panels?
    I look forward to an explanation.
    Thanks.
     
  2. gfreek

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    They are both using the same panel, on the pz70 Pana have tweaked the driver to double the CR (pre-burn was lowered to increase contrast).
     
  3. Bumtious

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    Contrast ratio is the difference between the very darkest parts and brightest parts of a picture.

    Take a scale of 1-100 1 being black, 100 being white.

    Some sets black with say 5 and go to 50 some will go from 10 to 70. The 10 to 70 has the biggest contrast ratio but the 5 to 50 will look more contrasty because the black is blacker.

    This is just one way the figures are fudged.

    You need to look for yourself, but looking at a pz70 and pz700 in a dark showroom in tottenham court road this week I could see no difference in the black pre charge level between these sets, there was also no difference in the brightness either. The px70 had a very very slightly lower level precharge, but went quite a bit brighter. But in the home you would not have contrast set this high so the ratios quoted are irrelevent. There is more than enough on both sets.

    Had another look today at Lakes in Marlow, again I could see no difference between the PZ70 and PZ700.

    Others are now saying the same.

    Why they are quoting this I dont know.

    But look for yourself. One way to check if you can, look at them in the darkest showroom you can find and put them onto an input with no signal, turn the brightness right down, and look at the pixel glow. To my eyes they were the same. This is the precharge level which has a major effect on picture contrast.

    If there was a 5000:1 difference it would be easy too see.
     
  4. Bumtious

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    Anyway just to add to the manufacturing spin (confusion)

    The Panasonic site and e shop both quote the:

    42 PZ700 site with 5000:1 contrast ratio with 4096 steps of gradation

    42 PZ700 Shop

    The Panasonic site quotes the:

    42 PZ70 Site contrast ratio at 10000:1

    The panasonic e shop quotes the:

    42 PZ70 shop contrast at 8000:1 with 2048 steps of gradation indicating processing is not as powerfull as the pz700. That gives an indecation where the corners have been cut to drop the price. Strangely states it has only 1 HDMI.

    Looks like they are not sure what to tell us.
     
  5. CHFels

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    The 2048 gradations spec is certainly an error on the website - all PZ70s come with the little sticker that says 4096 :) But I'm ready to believe that the panel is basically the same as the PZ700 - but not inferior. The electronics are confirmed to accept a 24fps input (I'm not saying what it does with it!), whereas the PZ700 does not - that's the one confirmed difference I know about.

    CHFels
     
  6. Bumtious

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    Chfels, I probably agree, they have cut the corners asthetically, but it just shows what a mess this is, how the hell are people supposed to make a choice when the manufacturer is getting its knic...s in a twist.

    You only have to look properly to see they are the same. Just trying to make people see the lengths manufacturers go to pull the wool over our eyes.

    At the end of the day dont always believe what you read.

    You cant even ring a manufacturer up and get a straight answer, (Pioneer, Panasonic and others, they are as bad as each other)

    But the reality is they have discontunued a product after 8 weeks in the case of the 42PZ700, why is that??? and basically (with better support for 24 fps but not total support) put in in a different skin, fudged the figures, cut back on features and dropped the price.

    Go look for yourself and judge, if you are happy then buy it.
     
  7. choddo2006

    choddo2006
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    Hi ******** - why isn't it "total support" for 24Hz? Am I missing something?
     
  8. CHFels

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    Right - they made 3 mistakes with the PZ700: priced it near the Pio 428/4280, too high if people look at them side by side; didn't make it 24fps compatible; and they announced a 5000:1 contrast ratio, lower than the claims made for the PX70. Marketing version of "Three strikes - you're OUT!". :rotfl:

    I think that since they saw they were only gonna sell 12 of these sets, they decided to bail out early, rush *up* the introduction of the PZ70, and get the PZ750 out as soon as possible. The PZ750 will be almost identical, but will admit 24fps, *claim* higher contrast, and still be slightly cheaper than the PZ700 - to stay clear of Pio territory.

    CHFels
     
  9. JeffD

    JeffD
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    I suspect the PZ70 is displaying 1080p24 at 1080p60 as the electronics are cheaper, ******** has mentioned a visit to Tottenham Court Rd so perhaps he's been able to test this???
     
  10. AliG

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    CHTels,

    Do you have any further details on the PZ750 spec or when it might be on sale - elsewhere on this site I think I read that it wouldn't be available to the UK market. (Another HDMI input wouldn't go amiss)

    AliG
     
  11. choddo2006

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    If they are, that's quite surprisingly rubbish.
     
  12. gfreek

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    Yes the pz70 does not do true 1080p/24fps instead it does a 3:2 pulldown i.e.60fps hence it's not officially mentioned on the spec by Pana. true 24fps support will be implemented in their G11 panel range for next year.
     
  13. JeffD

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    Another error that keeps coming up, the PZ70 was always going to be introduced as a budget version of the PZ700, all they've done is tweak it so it accepts 1080p24 and played with the CR ratio. A simple search of this forum will reveal posts on the PZ70 from as far back as March including one of my own

    http://www.avforums.com/forums/showpost.php?p=4439280&postcount=25

    With the PZ750, if we do get it and it's the same as what's being released in Japan then it does appear they've made a change to the way the electronics drives the panel resulting in deeper blacks.
     
  14. Bumtious

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    I did not want to say that but there is something stopping them claiming 24 frame support.

    When I saw them togther there was the whole panny plasma range along with the Pio's the camerea pans were not smooth with the panny's, any of them, it was not bad but not where it should be if it had proper support. Tt had nothing to do with settings either.

    Dont get me wrong, there was a liitle more detail with the 1080p sets, close up, 3ft or so, but that was lost with movement.

    Again my point, there is no point having this extra resolution if it cant be taken advantage of with the proper processing.

    Which is why I suggest waiting for the correct support.

    It like having a car with 5 gears but you can only use 4.
     
  15. Bumtious

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    That is a different territory, french, the uk 2007 magazine I saw in Lakes yesterday had no mention of this product.

    There are different spec sets all over the world to satify that market.
     
  16. JeffD

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    That proves that this is not some rushed product and has always been on the roadmap for release in the european market, if you look at the pictures the design is as released, and the only change in the spec is the CR ratio.
     
  17. Icm76

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    Is this specifically to do with deinterlacing and/or scaling of the generic 'Viera' processing? You make it sound as though the PZ is no better than an lcd?

    What I'd like to clarify - if you use the PZ as a monitor fed with 1080p from a Blueray, HD-DVD, PC or Lumagen processor why would it lose detail if the image is moving?
     
  18. Jonstone

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    I think this is less to do with what the screen is actually displaying and more to do with what your eye can actually take in.

    If you compare still images of different resolutions you can pick out the improvements with the higher res relatively easily, but as soon as you introduce a reasonable amount of movement into the image your ability to differentiate between the two diminishes
     

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