Quantcast

50" Plasma - not 16:9

Reiner

Active Member
Did see a 42" and 50" side-by-side and the 50" looked likes it squashes objects or rather enlarges them vertically, i.e. people look taller/thinner and balls aren't round but oval shaped.
On the 42" the proportions looked perfectly ok.

So are 50" plasmas only taller but not wide enough to maintain a true 16:9 aspect ratio?
 

johndon

Active Member
I've noticed this as well on the 50" Pioneer I'm thinking of getting. I've only seen it in one shop so far and didn't get a chance to have a good look. I'm hoping to have a side by side demo of the 43 and 50in Pioneers this weekend so hopefully I'll be able to find out why the picture on the 50in looks so different.

John
 
M

mikeq

Guest
Hi,

I think it is just due to the size of the image that it is more noticeable on the 50".

The ratio of 16:9 is 1.778

The 50" set dimensions are 47.8" x 28.7", ratio 1.665 and the 42" set dimensions are 40.2" x 24" ratio 1.675. Not much between the 42" and 50" ratios. Neither are truly 16:9 so both will make circle look oval.

For the sets to be truly 16:9 the 50" screen would need a width of 51" to the 28.7" height. The 42" would need a width of 42.6" to the 24" height.

This is based on the Panasonics and their set dimension not the screen dimensions, but I would imagine the frame is the same size all the way around so the ratios wouldn't change.

The 43" pioneer works out at 1.698 closer to 16:9 but still not exactly.

Am I thinking along the right lines here? or is this complete b****cks?

Mike

This is when viewing things at full screen, if there are black bars top and bottom then circles should look circular.
 

johndon

Active Member
You're probably right Mike, the one I saw was playing a movie full screen so it is possible it wasn't being show at the correct aspect ratio.

John
 

delta

Banned
I used the THX video setup to check my Panasonic 50" and the circle is perfectly round in each mode. I have never seen perfectly round circles before on any kind of tv, they tend to be slightly squashed.
 
M

mikeq

Guest
It really depends on what ratio the image was intended to be displayed.

a 16:9 created circle image which is being stretched to the top and bottom of the screen (i.e. no black bars) will not appear round unless the screen ratio is exactly 16:9 (which most aren't). I haven't seen a THX setup thingy but if there is a 4:3 circle image what happens when you play it at 16:9?
 

phil_evans

Standard Member
Mikeq,

Forgive the mathematician in me, but your comment about equal size borders is incorrect. I.e.

16 / 9 does not equal (16+b)/(9+b) if b>0

So you do need to consider the visible screen dimensions rather than the frame.

The (W/H in mm) calculations for the Pioneers (to 3dp) are:

503MXE: 1098.2/ 620.5 = 1.770
433MXE: 952.3/ 536.1 = 1.776

So the 433 is "truer", but remember the pixels are more rectangular on the 433 (not that the 503 pixels are perfectly square either).

The figures for the old Pannys are:

TH50PH3D: 1106 / 622 = 1.778
TH42PWD4: 920/ 518 = 1.776

So the 50" Panny is the truest. It also has the "squarest" pixels of the bunch.

Do I win the award for saddest post of the day? :blush:

Phil
 

ajb

Active Member
Hi

I wanted to say that I thought it was an excellent and informative post, even if it was a little sad. It also reminded me of the dark days when I did a degree in mathematics...

I am normal now!

Regards
Andrew
 
M

mikeq

Guest
Originally posted by phil_evans
Mikeq,

Do I win the award for saddest post of the day? :blush:

Phil
No Phil you don't, I do for starting the maths bit and getting it wrong:blush: I knew I should have searched harder for the screen dimensions:eek:
 

phil_evans

Standard Member
ajb,

I did maths at Uni too but rarely use any of it these days. I would hope I could still cope with Joe's homework (assuming it belongs to his kids anyway):D

mikeq,

The screen/ pixel dimension stuff does get confusing, especially when you consider a computer graphics card driving a Pio 433 or 42"HD Panny. If you want to drive these rectangular pixelled screens at native 1024x768 rate (e.g. through DVI), you'd need some pretty weird Windows drivers to render a "square" image. Does my head in anyway. I think its easier to use a WideXGA-type driver (e.g. 1366x768) and just cope with losing a few pixels horizontally.

Phil
 

Similar threads

Top Bottom