An ISF Opinion on Sky Contrast Setting

Silver Serpent · 06-03-2009, 1:49 PM

Hi,

I've done alot of reading on what is the correct contrast setting for a Sky Receiver and my initial findings were that Medium was correct, which does look best to me.

However, I've since read of ISF calibrations being performed where the Low setting was recommended (on a Thomson box), and another where the calibration was peformed with the setting on Medium (again a Thomson box I believe).

The following article recommends Low for Thomsons:

Sky Plus and Sky HD Contrast Setting - Telly Toad

I'm at the point now where I felt I had to ask the question here to try and get a definite answer as to what's best to use and a reason for it.

Is there an actual correct setting, or do different calibrators prefer to use different contrast settings just as a starting point with the results ending up the same in the end?

Any information would be appreciated.

Thanks.

Piers · 06-03-2009, 10:33 PM

8+ hours since you posted this and nobody has yet replied!

For me it isn't an easy and obvious answer. Thomson boxes were all that were available in the very early days. Low contrast gave far and away the best picture and I continued to use this when Sky+ boxes appeared. I had a Sky+ box at home and was convinced that low was the best option.

Sky HD then appeared - Thomson only. I got one of the first and initially set it to low contrast. It looked good but I then started experimenting. After hours of playing around I convinced myself that medium was better. It wasn't obvious as low and medium settings needed different settings on the display.

I had never heard of TellyToad before today but in essence I don't agree.

Low for vanilla Sky and Sky+. Medium for Sky HD (Thomson). No experience of the other Sky HD boxes.

Flame suit on.... anyone else willing to step up?

Silver Serpent · 06-03-2009, 11:56 PM

Quote:

Originally Posted by Piers

8+ hours since you posted this and nobody has yet replied!

For me it isn't an easy and obvious answer. Thomson boxes were all that were available in the very early days. Low contrast gave far and away the best picture and I continued to use this when Sky+ boxes appeared. I had a Sky+ box at home and was convinced that low was the best option.

Sky HD then appeared - Thomson only. I got one of the first and initially set it to low contrast. It looked good but I then started experimenting. After hours of playing around I convinced myself that medium was better. It wasn't obvious as low and medium settings needed different settings on the display.

I had never heard of TellyToad before today but in essence I don't agree.

Low for vanilla Sky and Sky+. Medium for Sky HD (Thomson). No experience of the other Sky HD boxes.

Flame suit on.... anyone else willing to step up?

Thanks for the response Piers.

I've a Thomson HD box and Medium definitely looks best to me.

I've tried Low and applied settings to suit, but I feel the picture loses a dimension.

Gordon @ Convergent AV · 07-03-2009, 9:46 AM

In my experience settings of anything other than LOW on a Sky plus resulted in, clipping white levels as the toad says.

On HDMI output of SKYHD boxes I look at actual picture content and actual broadcast test patterns when they are available. So far I have not seen any reason to go to low setting on the boxes I have come across. YMMV.

Martin J. · 08-03-2009, 3:29 AM

For those not reading the thread in the HD forum and to cut a long story short, I always said medium was best on the Thomson HD box, but when my system was calibrated, the low setting was used.

I have two displays connected via HDMI, a modest Panasonic TH-37PX80 in my office (not calibrated other than via Video Essentials) but in my main room a DVDO VP50Pro and Pioneer KRP-500M, both calibrated.

As Mr. Serpent has given me a bad case of paranoia, I've experimented today with both displays, with and without calibration enabled. If I make sure the contrast controls are low enough on both displays to avoid clipping, I can actually see some loss of highlight detail on the BBC preview loop with the HD box set to anything other than low, which is contrary to what I originally posted. The best example is some sort of comedy clip with John Thomson (the guy from Cold Feet) where almost the entire image is approaching peek white in some scenes. So I think, with and without calibration, low actually looks best to me.

If it helps at all, I can capture the component outputs of the box. Unfortunately I have no way to capture the HDMI outputs. Here's what I've got on that front - which may confuse things further and if anyone can offer better analysis, it would be appreciated.

This is from the BBC HD blog:

"What have I done and how useful is this version of the test card? First, white level has been reduced so the peak white box is not 100% (level 235 or 0.7v). The super white spot is now 100% and the linearity of the grey scale is now slightly inaccurate. [snip] The top white block has two spots. As I said earlier, usually the white block is peak white with the right spot higher (super white) and the left spot slightly lower. On our test card, the levels are slightly reduced."

Here are my captures:

BBC HD test card - low contrast.

In Photoshop, I measure the white block as 215 and the super white block at 220. That may (or may not) be consistent with the text from the BBC blog, because according to them, the level shouldn't be 235. Either way, it would only take a small contrast adjustment at the display level to reach 235, which is what that site is recommending.

BBC HD test card - medium contrast.

I'm measuring the white block at 254 and the super white block at 255, which means it's most definitely clipped. Remember, according to the BBC the block(s) should be below 235.

BBC HD test card - high contrast.

Just for kicks. Ouch.

I was going to take a stab at grabbing the transport stream from the box, but my 1TB drive is 75% full of stuff we haven't watched and I don't fancy risking the SO's wrath if it goes walkabout. It would be really interesting though if anyone could access the TS via a PC.

StooMonster · 09-03-2009, 9:30 PM

I've got a BlackMagic Design Intensity card, a PCIe card that captures HDMI uncompressed to hard disk on Mac or PC.

When is BBC HD Test Pattern transmitted?

Although my Workstation PC and Sky HD box are in different rooms; I have FreeSat box in my office that I could capture, but that's not the one in question is it?

StooMonster

Iain Gibson · 10-03-2009, 11:04 AM

Info about the BBC HD test card on:
BBC Internet Blog
In particular,

How to record the BBC HD test signals
The HD test card is just over 1 hour into the promo and the AV sync signal is 50 minutes later. To record both signals, check the time the last programme finishes and add 1 hour. So if the last programme ends at 01:30 set your PVR to record from 02:25 to 02:45 for the test card and 03:15 to 03:35 for the AV sync signal.

(The "AV sync" signal is a lip-sync test.)

Silver Serpent · 19-06-2009, 5:21 PM

I found this post from Bumtious so thought I'd add it to the thread:

Pioneer 9G Owners Thread

-----------------------------------------------------------------------

It must be set on medium.

High clips white, and there is nowhere near enough high freqencies on low.

-----------------------------------------------------------------------

I changed my opinion for a short period of time thinking Low was better, but it was only short and I went back to Medium again.

Medium is definitely the correct option for a Thomson HD, so it's case closed for me.

The chances are it will be the same for the Samsung, Pace and Amstrad (when it becomes adjustable) too.

Silver Serpent · 16-07-2009, 8:53 PM

I've checked the Pace HD Box and LOW seems to be the correct setting, just like it's little brother, Sky+.

That's just my initial opinion though. I could be wrong and Medium may be correct.

The contrast setting seems to behave in a different way to the Thomson HD Box.

Meridius · 07-08-2009, 11:57 PM

hi there i have a lx5090 and would like to know what i should set my sky + pace box to should it be low or medium ?

does it matter when you use the user or movie mode for the contrast setting on sky ?

also is there anyone that can do a cal isf near newcaslte for this tv

thanks

Gordon @ Convergent AV · 09-08-2009, 11:20 PM

IAN at illuminant is your nearest guy. Piers and myself are probably nearby often. Id suggest you contact your preferred guy direct...distance is not always a problem.

Silver Serpent · 10-08-2009, 10:50 AM

Quote:

Originally Posted by Meridius

hi there i have a lx5090 and would like to know what i should set my sky + pace box to should it be low or medium ?

I presume you mean a non-HD Pace box?

If so, it should be Low.

Iain Gibson · 10-08-2009, 11:48 AM

Quote:

Originally Posted by Meridius

also is there anyone that can do a cal isf near newcaslte for this tv

thanks

Hi Meridius,

I am based in N. Yorks. and have had a couple of ISF clients in Newcastle. Feel free to PM me for further info, pricing &c.

Cheers,
Iain

Meridius · 10-08-2009, 6:08 PM

Quote:

Originally Posted by Silver Serpent

I presume you mean a non-HD Pace box?

If so, it should be Low.

yes mine is the normal SD sky pace box, i have mine set at medium

Q1 why do you need to set it low ? is it the sky hd that needs to be set to medium.

Q2 I use user mode with drive mode 1 for sky as movie mode is abit flat and dull this is why i am after a ISF doen as i have herd that you get the pop of user mode and the natrual colour od movie mode all in one with the correct gamma.

yes i know i should use drive mode 2 for sky but i ahve the flashing problem with my tv when using user and drive mode 2 and only stops when using drive mode 1 or using movie mode with drive mode 2.

I am in with talk with pioneer at the moment about this as i have also read that it also flashes in the isf dat/night mode using drive mode 2 which could casue problems for me.

i just hope there is a firmwear update to fix this as i have herd the 2009 models do not do this but pioneer have never herd of this problem which is stange as alot of 5090 owners seem to ahve the same problems as me.

Dave M · 10-08-2009, 8:09 PM

I was always of the opinion that it should be set to medium?

Silver Serpent · 11-08-2009, 9:17 AM

Quote:

Originally Posted by Meridius

yes mine is the normal SD sky pace box, i have mine set at medium

Q1 why do you need to set it low ? is it the sky hd that needs to be set to medium.

It needs to be set to Low because Medium and High 'Clip White', i.e. you lose detail in the bright parts of the image.

An example of this would be someone wearing a white shirt where alot of the detail may be lost, such as the buttons, creases etc...It would be like you erased them in Paintshop.

If the contrast is set too high at the source, there is nothing you can do at the display end to restore the lost detail.

Silver Serpent · 11-08-2009, 9:21 AM

Quote:

Originally Posted by Medz1

I was always of the opinion that it should be set to medium?

What's right can, and does, vary between types of boxes and manufacturers models.

Medium is definitely right for a Thomson HD Box.

I have a Pace HD with a few weeks and my initial thoughts were that Low was correct, but after more experimenting I'm not sure.

I'll post photo's later showing why I thought Low was right.

Dave M · 11-08-2009, 5:39 PM

Come to think about it my calibrator (Iain from illuminant) said medium was right for me.

Meridius · 11-08-2009, 8:19 PM

so sky hd boxes need to be set to medium and sky + boxes need to be set to low (i have a pace sky+)

Silver Serpent · 12-08-2009, 9:27 AM

Quote:

Originally Posted by Meridius

so sky hd boxes need to be set to medium and sky + boxes need to be set to low (i have a pace sky+)

Low for a Pace Sky + Standard Definition Box.

Medium for a Thomson Sky HD Box.

There is nothing concrete on the other makes of HD box yet, but as I said, I initially thought Low was correct for a Pace HD (post new EPG), but I'm not so sure anymore now that I've had a few weeks to experiment.

I'll get photos up ASAP showing why I initially thought Low was correct.

Meridius · 12-08-2009, 5:54 PM

Quote:

Originally Posted by Silver Serpent

Low for a Pace Sky + Standard Definition Box.

Medium for a Thomson Sky HD Box.

There is nothing concrete on the other makes of HD box yet, but as I said, I initially thought Low was correct for a Pace HD (post new EPG), but I'm not so sure anymore now that I've had a few weeks to experiment.

I'll get photos up ASAP showing why I initially thought Low was correct.

sorry for all thw questiosn but how do you know the sky+ box should be set to low as you have doughts on your hd box ?

is tehre a calibrater on here can confirm that these need to be set to low ?

Silver Serpent · 13-08-2009, 9:46 AM

Quote:

Originally Posted by Meridius

sorry for all thw questiosn but how do you know the sky+ box should be set to low as you have doughts on your hd box ?

is tehre a calibrater on here can confirm that these need to be set to low ?

Those questions have already been answered.

Read the thread through again.

If you weren't a regular, I'd think you were winding me up

FatherJack · 05-09-2009, 3:44 PM

Interesting thread!

Anyone have any experience with the new Samsung SkyHD box yet? Thought I'd ask since there have been no new posts here for a couple of weeks.

I've recently taken delivery of a new TV (Panasonic TX-L37V10B) and had SkyHD (Samsung box) installed at the same time, so I'm still at the fiddling around stage ...

Nik555 · 05-09-2009, 4:04 PM

Quote:

Originally Posted by FatherJack

Interesting thread!

Anyone have any experience with the new Samsung SkyHD box yet? Thought I'd ask since there have been no new posts here for a couple of weeks.

I've recently taken delivery of a new TV (Panasonic TX-L37V10B) and had SkyHD (Samsung box) installed at the same time, so I'm still at the fiddling around stage ...

When Gordon came round he calibrated my Samsung HD box on medium.

Nik

Ivor_Biggern · 04-10-2009, 6:57 PM

In my opinion their is no right or wrong settings, its all down to personal preference and what looks best to you. Some people like a brighter picture and some prefer it slightly less bright, some people prefer more colour and some people prefer less colour, i think the only opinion that matters should be your own as its your viewing expoerience.

I appreciate what the more knowledgeable people say about the various settings where whites maybe clipped etc but at the end of the day its all down to personal preference.

StooMonster · 27-11-2009, 10:34 PM

Yes, you either want the settings calibrated to match an internationally agreed standard of colour reproduction or you don't.

Anyone captured the BBC HD test cards digitally yet? I also wonder how FreeSat comes into the equation, as it has no HIGH-MEDIUM-LOW contrast settings and I think it's picture quality is better than Sky HD.

StooMonster

Gordon @ Convergent AV · 28-11-2009, 9:06 AM

Stoo: If you go to the BBC technical blog web space you can probably find the post from their head guy explaining how the BBC test card uses incorrect signal levels, intentionally. They were scared someone might nick their test pattern and resell it so they made it wrong but BBC engineers are aware of the offsets required for some measurements.....idiots.

Silver Serpent · 06-12-2009, 1:26 PM

Quote:

Originally Posted by StooMonster

I also wonder how FreeSat comes into the equation, as it has no HIGH-MEDIUM-LOW contrast settings and I think it's picture quality is better than Sky HD.

StooMonster

With FreeSat it would just pass straight through untouched leaving calibration solely at the display end.

That's how the Sky HD box should operate too in my opinion, although the Medium setting for most HD boxes (if not all), does seem to be a pass through, or the closest to it.

mksuperhoop · 23-01-2010, 10:14 PM

Quote:

Originally Posted by Silver Serpent

Low for a Pace Sky + Standard Definition Box.

Medium for a Thomson Sky HD Box.

There is nothing concrete on the other makes of HD box yet, but as I said, I initially thought Low was correct for a Pace HD (post new EPG), but I'm not so sure anymore now that I've had a few weeks to experiment.

I'll get photos up ASAP showing why I initially thought Low was correct.

hi,
i've just come across this thread and wondered what your final thoughts are for the pace HD box - low or medium?
thanks

Silver Serpent · 25-01-2010, 1:12 PM

Quote:

Originally Posted by mksuperhoop

hi,
i've just come across this thread and wondered what your final thoughts are for the pace HD box - low or medium?
thanks

I'm not certain, but the Pace Box is currently being used on my Samsung LCD with Contrast set to Medium.

90% of my viewing is done on my Plasma, and I went back to using the Thomson with that, which gave a superior image I thought. The Pace looks much better with the Samsung though.

From the experimenting I did, I do think the contrast behaves differently on the Pace compared to the Thomson though.

By the way, I never posted those photo's I said I would when I initially thought Low was correct on the Pace, as I ended up deleting the example content I had stored when swapping the boxes around.