Dynamic Contrast vs. Regular Contrast Ratio??

[JJ]

Is it something like actual and nominal values in construction measurements?
Which number should I go by, and what really is the difference?

[HDJK]

Dynamic contrast adjusts the brightness according to the image present. This boosts the difference between the darkest dark and the brightest bright, but it can cause pumping of black levels in particular. The Sony XBRs cannot turn it off (according to this review). Not much of a problem once it's calibrated properly, but most other TVs can turn it off.

Numbers can lie, go with what your eyes tell you.

[gvortex7]

Both Dynamic and Static contrast rations have their faults because they both omit certain elements that influence luminence whether it's due to the display or the reflectiveness of the room. Plus all tests are done in an ideal viewing environment (total darkness) which is often impossible to achieve.

[JJ]

Vortex - ironic, we live in the same city,

[JJ]

So basically, I should go with the highest available ratio? That would be the uhh, main bullet point of this presentation?

[gvortex7]

Originally Posted by JJxiv1215

Vortex - ironic, we live in the same city,

Cool, great to see another local Blu-ray supporter.

Basically having a high value for either contrast ration types is pretty good, but make sure that light can be somewhat controlled in the room you're planning to view your television in. One thing to note though, the higher the maximum lumen output of your display the better chance you have of being able to view it in any light conditions. That's why in this area LCDs would be superior to most other type of displays.

[JJ]

Thanks. I was looking to upgrade my television to 1080p, but with a $1500 budget, I had to look into every option - the Sony models and Samsungs that most recommend are out of reach. Philips and Sharp seem to be at the top of my list, and since black levels were my primary concern with my Vizio - I felt I should learn fully about contrasts. Thanks again.

[gvortex7]

Originally Posted by JJxiv1215

Thanks. I was looking to upgrade my television to 1080p, but with a $1500 budget, I had to look into every option - the Sony models and Samsungs that most recommend are out of reach. Philips and Sharp seem to be at the top of my list, and since black levels were my primary concern with my Vizio - I felt I should learn fully about contrasts. Thanks again.

Get the 42" 1080p Philips LCD TV, m/n 42PFL7432D. That's what I got my parents and it's a terrific TV. Even standard def televison programming looks good on it. Blu-rays are phenomenal looking. I highly recommend it.

You can get it for less than $1500, just research it.

[JJ]

Thats exactly the one I was looking at, haha - the Ambilight.

[gvortex7]

Originally Posted by JJxiv1215

Thats exactly the one I was looking at, haha - the Ambilight.

It's telepathy my friend.

[JJ]

Must be that 954 connection.

[gvortex7]

Originally Posted by JJxiv1215

Must be that 954 connection.

LOL

[JJ]

Although Im going to assume you've lived here longer than I - 11 years here now, half my life.

[gvortex7]

It's been 15 for me which is one year shy of half my life.

[doctorsteve]

OK, so a tv without dynamic contrast would always use the same "level" of contrast (like when you adjust a 'slider' in the GUI of the menu screen), but in using dynamic contrast, the contrast is always readjusting the contrast, depending on whether it's a light-rich scene versus a black-rich scene???

Long story short - what's the big deal?

WHY is it bad if an image CR is lower than the dynamic?
WHAT is the type of problems I'd see?
Please tell me WHY I should care about the dynamic and image CR, and what is considered an acceptable static and dynamic for an LCD? I'm itching to buy a Bravia XBR4, but some people say things that make me think it's not up to snuff because of it's CR's. (18,000:1 dynamic, 1000:1 image)

Help, you wizards of video!!! Thanks a ton...

The Doc

[Brandon B]

You are actually talking about three types of contrast. There is the standard measured on/off contrast ratio. Usually measured as the peak white level for an all white screen, vs. black level for an all black screen. For this to be a meaningful measurement, this should be measured after calibrating the display, as it is easy to pump this number up by max'ing out the display, but you would never watch material with it set like that. However, a lot of mfrs in fact boost their numbers by doing so.

Dynamic contrast is gnerally accomplished by varying the light source intensity, which allows you to give the appearance of better on/off, by varying the peak white and black levels. So in a dark scene, the light source has its level reduced to lower black level, but in a bright scene, raised to give higher peak white.

Instantaneous contrast, also called intra-scene or ANSI contrast, refers to the peak white level vs. black level in a given single image. ANSI is actually in reference to a specific test pattern (4X4 checkerboard of black and white rectangles), but it gives a good idea of the simultaneous contrast of a display.

On/off and dynamic generally give a good idea of how the display will perform on dark material, and simultaneous contrast more affects the image in bright scenes.

BB