I'm trying to figure this out because I'm thinking of a 40" but that'll block my cameras view and be too big for me so I'm thinking 30" but it might be too small. This might be an interesting topic for you guys to tackle. :)
I'm using a 65" myself lol
There are LOT of concerns today with 4k gaming... There are scaling issues, the fact that you need SIGNIFICANT graphics horsepower with TONS of video memory to run 4k, etc.
For example... I have a Core i7 4770k, 2 SSDs in a Raid0 (1GB read and write), 2x GTX 770 in SLI, 16GBs of DDR3 2400, and I have to turn a lot of the settings down to play at 4k res. In addition to this, I run into some weird anomalies on the desktop. The HUD in games can be incredibly small and hard to read due to the scaling, and other random issues. Instead, I play games at 1080p and turn the graphics settings to the MAX and they play just fine. I did notice an issue with Dragon Age, crashing if I don't change my desktop res to 1080p before starting the game.
So be prepared to run into these kinds of issues if you take the leap into 4k now. Based on reviews, even GTX 980s in SLI can struggle at 4k with some games... we need the next gen of graphics cards to arrive so we can play at that high of a res!
To answer your question... see here:
http://referencehomethea...ommentary/4k-calculator/
and here:
http://www.rtings.com/in...to-distance-relationship