Connect to 4K TV at lower resolution?

[andy9l]

Although I'm referring to a MBP in this thread, I think this is a broader OS X El Capitan question...

We're looking to buy a 4K LG webOS TV in the next few days and would like to connect an old 15" 2009 MacBook Pro to it on the odd occasion. The MacBook currently sits as part of our multimedia suite and we do use it now and then - I've put an SSD in it so it's great for basic stuff.

I recognise the MBP cannot run 4K, nor do I want it to, but will I still be able to push 1080p or another scaled size? Or does OS X simply say "no" to any form of connection. I currently connect to our TV with an Apple Mini-DisplayPort to DVI adapter and a third-party DVI-male to HDMI-male cable.

Thanks for any advice/pointers.

 

[beebarb]

It's not really even an El Capitan question.

No, no operating system will ever block you from connecting a devices lower resolution output to a higher resolution screen.

Back when CRTs were common, and I was using MS-DOS and Windows 3.1, I had a monitor technically capable 0f 800x600.

But, the graphics card couldn't do that.

640x480 in Windows 3.1, and often the MS-DOS standard 8:5(16:10) resolution 320x200 vertically stretched to the equivalent of 320x240 by the 4:3 display when playing DOS games.

If you want a more recent example, when I had my 2006 model iMac, I'd occasionally connect it to my LCD TV.
I intentionally set the iMac to use 800x500 when connecting to the TV, which technically had a native resolution of 1366x768.

 

[andy9l]

Thanks for the response - makes sense.

So I should be able to hook it up...it'll just offer me resolutions of 1080p, etc. in System Preferences?

 

[beebarb]

Thanks for the response - makes sense.

So I should be able to hook it up...it'll just offer me resolutions of 1080p, etc. in System Preferences?

Yes, it will offer any resolution up to the maximum the display configuration allows.
Some resolutions your graphics card isn't capable of outputting effectively may be listed as an option as well.

So 1080p (1920x1080) will be no problem.

 

[andy9l]

Yes, it will offer any resolution up to the maximum the display configuration allows.
Some resolutions your graphics card isn't capable of outputting effectively may be listed as an option as well.

So 1080p (1920x1080) will be no problem.

Great, thanks for the help!

 

[Fishrrman]

I'm wondering if this depends on what options your tv offers?

I don't yet own a 4k tv, just getting interested at this time, but it seems that most (all?) of them have an "upscaling" feature that can take a 1080p input and "process it up" to full 4k, at least for signals coming in at the "broadcast" level.

I'm thinking that it might also work with 1080p input from the computer, as well.

If not, perhaps the tv controls give you the option of running it in 1080p-only mode...

 

[andy9l]

All of them offer upscaling, otherwise regular TV watching would take up only a fraction of the screen!

 

[h9826790]

For TV, you may need to set it to "computer mode / game mode" to use as monitor (reduce input lag), in this case, the TV may not offer you any upscaling. However, it will simply use 4 pixel to represent 1 pixel input, so, still display in full screen, but no upscale (interpolate the missing signal between pixels).

IMO, upscale means convert the single output to a higher resolution picture, but not simply use more pixels to display the picture with lower resolution.

Anyway, I use LG 4K TV as well, you can simply use it as 1080P monitor if no 4K signal avail.

 

[andy9l]

For TV, you may need to set it to "computer mode / game mode" to use as monitor (reduce input lag), in this case, the TV may not offer you any upscaling. However, it will simply use 4 pixel to represent 1 pixel input, so, still display in full screen, but no upscale (interpolate the missing signal between pixels).

IMO, upscale means convert the single output to a higher resolution picture, but not simply use more pixels to display the picture with lower resolution.

Anyway, I use LG 4K TV as well, you can simply use it as 1080P monitor if no 4K signal avail.

Thanks for the response – great to hear from someone with a LG 4K TV.

I think you're right with your understanding of 'upscaling'. I had assumed it was the same as the retina screen scaling as you've described – ie. 1px = 4px.

Going to pick it up tomorrow