When is comes to big televisions, can you have too much of a good thing?
Television makers love to show off their inches and play "mine is bigger than yours". They enjoy rolling out 100+ inch televisions at trade shows - massive screens which your average person could never afford or even squeeze into their house.
Big is certainly beautiful, but don't succumb to screen envy. Even if you've got cash to splash, you need to be realistic when choosing a television for your lounge room.
Optimal viewing distance
Videophiles will tell you the optimal viewing distance for Full HD 1080p content is around 1.5 times the size of the screen, remembering screen sizes are measured diagonally. Any closer and you can see the individual pixels in the image.
Any further away and you start to lose the fine details. For a standard-def picture, such as a 576p PAL DVD, you can move back to around 4x the screen size without losing much detail.
This sounds like a great rule of thumb until you do the maths - the optimal viewing distance for 50 inch 1080p television is around 2 metres. For your average punter that's just crazy. You might see every fine detail in the image, but for most people it's just not comfortable or practical.
Field of vision
I've got a 46 inch high-def Bravia and I admit that I occasionally push the couch that close to watch a Blu-ray action movie, with headphones on after everyone else has gone to bed. I certainly wouldn't want to sit that close all the time, especially when there are a few people trying to watch the same movie.
Remember you're not trying to fill your field of vision - otherwise you'd constantly be turning your head to see everything. By my rough calculations, at 2 metres the television takes up just over a quarter of my field of vision and it's already verging on uncomfortable.
A rule of thumb to follow
For your average viewer, 2x the screen size is about as close as you'd ever want to sit to the screen even if you're watching a Blu-ray movie. This means about 2.5 metres for a 50 inch television if you want to really immerse yourself in a high-def movie. For standard-def viewing you want to push your couch back to the 4 metre mark.
If you can't sit at least 2.5 metres away from your television, I'd have serious reservations about buying a 50 inch HDTV.
Buying a flat screen TV? Have a question you'd like us to answer? Add your comments or questions about flat screen TV issues to the discussion below.
Also in this series, How to Pick a Great Flat Screen TV, And Not Get Sucked In By Marketing Hype:
Part 14: Should I care about refresh rates?
Part 13: How do I compare HDTVs in the store?
Part 12: Hiding your television
Part 11: calibrating your television
Part 10: those pesky upscaling issues explained
Part 9: video inputs and future proofing
Part 8: Logitech Harmony vs AV Link remote controls
Part 7: Should you upgrade your TV for DLNA?
Part 6: TV tuners and "Digital Capable"
Part 5: HDMI and component ports
Part 4: LED and backlighting
Part 3: Screen size
Part 2: Refresh rates
Part 1: Brightness and contrast ratios
Also see our 5 tips for buying a digital TV set top box
And also see the lowdown on Freeview, and whether you should care
If you're new to Digital TV, or have yet to make the leap, start by reading Prepare yourself for Digital TV