DVI/HDMI vs VGA

[mobiusnz]

I have just brought a Viewsonic 37" LCD Tv - gotta say I'm pretty happy with it. I've been running it with a standard 2m VGA Cable. I've had a problem since I changed from an Nvidia to a Radeon card that the signal wasn't auto adjusting properly and was taking a bit of fiddling to get the picture right (horizontal position etc). Today while at a cabling wholesaler I purchased a DVI to HDMI cable and came home and hooked it to my Radeon X300SE's DVI port and low and behold the pc auto detected the new display and enabled it at the right resolution. My problem is that the picture is blooming, that is the white text under the icons at the desktop etc are very bright and blooming out a lot. I've played with the contrast, brightness etc and its a little better now but I would have expected instantly as good as the VGA, the position etc looks perfect instantly so the digital signal is working better on that front.

Has anyone had any similar experiences with this, are there tools out there for tweaking the Digital output from the cards?? Is this due to it being a cheap cable (I thought with digital over 2M even a cheap cable should be perfect?). Is it a bad pairing?

Any thoughts anyone?

[Koenie]

Is this also one of those odd 1366x768 resolution LCD's. Mine too and I found out that on HDMI it will not accept the native resolution. The TV will only accept the standard HDTV resolutions and rescale producing ugly artefacts. I drive my set trough the standard VGA cable now after manually setting the correct resolution (was also not autodetected). This produces much better images.

[mobiusnz]

Is this also one of those odd 1366x768 resolution LCD's. Mine too and I found out that on HDMI it will not accept the native resolution. The TV will only accept the standard HDTV resolutions and rescale producing ugly artefacts. I drive my set trough the standard VGA cable now after manually setting the correct resolution (was also not autodetected). This produces much better images.

Mine is running at the right res, I can force 720/1080 modes in the menu but it also detects and runs at the native panel resolution - Its just that the picture looks "odd" in pc mode. Interestingly it looks great watching GBPVR recordings like this, they look sharp have great contrast. I guess its the TV optimising the contrast etc for watching movie content not looking at a desktop.

[Pob]

I have just brought a Viewsonic 37" LCD Tv - gotta say I'm pretty happy with it. I've been running it with a standard 2m VGA Cable. I've had a problem since I changed from an Nvidia to a Radeon card that the signal wasn't auto adjusting properly and was taking a bit of fiddling to get the picture right (horizontal position etc). Today while at a cabling wholesaler I purchased a DVI to HDMI cable and came home and hooked it to my Radeon X300SE's DVI port and low and behold the pc auto detected the new display and enabled it at the right resolution. My problem is that the picture is blooming, that is the white text under the icons at the desktop etc are very bright and blooming out a lot. I've played with the contrast, brightness etc and its a little better now but I would have expected instantly as good as the VGA, the position etc looks perfect instantly so the digital signal is working better on that front.

Has anyone had any similar experiences with this, are there tools out there for tweaking the Digital output from the cards?? Is this due to it being a cheap cable (I thought with digital over 2M even a cheap cable should be perfect?). Is it a bad pairing?

Any thoughts anyone?

The best picture you can get on an LCD -via VGA or HDMI -is when you use 1:1 pixel mapping - I think on the viewsonic that means setting the res to 1360*768 yourself. This resolution is not automatically given as an option in the display drivers as it is not a standard HDTV res.
And it is not "odd" to have an LCD with this native res, nearly all the LCD TV's (not monitors) before the new 1080P LCD's are 1366*768 panels.
Using 1:1 LCDs do not usually enable you to adjust the colour, contrast etc - they are driven entirely by the PC, so you need to adjust the settings in your video card software.
However I have found on my LCD that when in 1:1 mode I have to turn down the backlight, or else it is just too bright and sharp - feels like it will disolve my eyes! So if you can adjust your backlight I would try that first.
Using 1:1 should give you a crystal-clear picture for general computer use and should be your starting point.
Pob
EDIT: After posting this I saw your new post in which you mention you are already using the native res. In that case the backlight is the only thing I can think of trying...

[mobiusnz]

The best picture you can get on an LCD -via VGA or HDMI -is when you use 1:1 pixel mapping - I think on the viewsonic that means setting the res to 1360*768 yourself. This resolution is not automatically given as an option in the display drivers as it is not a standard HDTV res.
And it is not "odd" to have an LCD with this native res, nearly all the LCD TV's (not monitors) before the new 1080P LCD's are 1366*768 panels.
Using 1:1 LCDs do not usually enable you to adjust the colour, contrast etc - they are driven entirely by the PC, so you need to adjust the settings in your video card software.
However I have found on my LCD that when in 1:1 mode I have to turn down the backlight, or else it is just too bright and sharp - feels like it will disolve my eyes! So if you can adjust your backlight I would try that first.
Using 1:1 should give you a crystal-clear picture for general computer use and should be your starting point.
Pob
EDIT: After posting this I saw your new post in which you mention you are already using the native res. In that case the backlight is the only thing I can think of trying...

I haven't looked yet but I don't recall seeing a backlight setting, I don't know if the brightness drives the backlight or not.... But backlight sounds like it as its like the Hot spots you get in whites with a projector.

Matt

[csy]

I have just brought a Viewsonic 37" LCD Tv - My problem is that the picture is blooming

Yep, same problem on my Viewsonic 32" LCD TV (N3240W).

It is specific to the HDMI input, and is caused by excessive sharpness correction. Lowering the sharpness to minimum should remove the blooming, however in my case I see the remains of the blooming as a double-ghost to the left and right of characters on the screen. (I would be interested if you see the same?) The supplier has seen the problem with their testing and represented the fault back to Viewsonic, however there has been no response from Viewsonic (3 months to date).

The other problem I have is that the EDID (for HDMI) does not provide 50Hz refresh rate at the native resolution, so I'm stuck with 60Hz and resulting micro-stutter - very annoying!!!

[mobiusnz]

Yep, same problem on my Viewsonic 32" LCD TV (N3240W).

It is specific to the HDMI input, and is caused by excessive sharpness correction. Lowering the sharpness to minimum should remove the blooming, however in my case I see the remains of the blooming as a double-ghost to the left and right of characters on the screen. (I would be interested if you see the same?) The supplier has seen the problem with their testing and represented the fault back to Viewsonic, however there has been no response from Viewsonic (3 months to date).

The other problem I have is that the EDID (for HDMI) does not provide 50Hz refresh rate at the native resolution, so I'm stuck with 60Hz and resulting micro-stutter - very annoying!!!

I see you are in CHCH too - probably came from Dove as well.... are you a dealer or an end user?

[csy]

Yes, Dove Electronics - Christchurch, end-user.

[csy]

I would really appreciate if you could also raise a fault with Dove, so we can together leverage support to get this fixed.