Macbook Air - Mini DP to HDMI on 4k TV Terrible Quality

[tommacbook]

Hi,

I have a Macbook Air 2013 on Mac OS Sierra, I have an oldish acer Monitor I have connected up as an external monitor using a Mini DP to VGA adaptor, the quality is pretty bad, but I expected it as its a crappy monitor and its using a VGA adaptor, I guessed those days have kind of gone?

So I changed to a Mini DP to HDMI adaptor and tried linking it to my new LG 55" 4k TV, and i thought it would be crisp despite the size of the TV I thought it would have found a resolution and fit the display.
But the text is blurry etc, pictures crap.

Any resolution for this?

Thanks for any help.

 

[Audit13]

The MBA cannot output native 4k signal.

It is my understanding that when a 4k tv receives a non-4k signal, it has to take the input signal and "unconverted" it to 4k. Upconversion quality will depend on two factors: quality of the input signal and the quality of the HDTV's upconverter.