When I was working out throw and seating distances and screen sizes for my setup I remember that the THX standard called for 36 degree and the SMPTE standard calls for 30 degrees of viewing angle. My setup gives me THX standard with a 100" 2.37 cinescreen viewed at about 2.8 metres - I watch a little further since I can see SDE at 2.6 metres or so if I look carefully.

It's no secret that I find much pleasure in continuing to enjoy the DVD format with the latest upscaling technologies... and this has proven a little paradoxical at times as I can see the increased detail in bluray without a problem... it's just that it doesn't give me a significant enough boost to prefer it always over the upscaled DVD....

I wondered why this might be... and last night I think I realised what it was.... no it wasn't just that I became absorbed in the movie and forgot about the picture quality...

I think it has to do with peripheral vision and the steep dropoff in sharpness or acuity that the eye has once it is viewing anything off the central macula.... a fact you can see for yourself if you try and read the end of this line or the beginning of it while you look at this WORD alone..... you really can't read the line a few above this one if you look only at this line...

So while you might have a 100" expanse of sharp picture.... unless you look around the picture at individual areas of sharpness then you're really only appreciating that sharpness at where your central vision or macula is directed.... people who do photography know that the focus of a lens is precarious and the difference between a sharp and blurry shot is touch and go sometimes.... anything behind or in front of the camera's focus is blurry....

So in fact.... if an upscaled DVD has good quality detail in the area that your eye is directed towards.... and much of this is large faces etc.... then the extra detail of bluray in the periphery is really missed.... of course it still looks better if one scans around the picture... but this isn't how we view a film....

And the difference is only apparent if you have a large enough screen and sit at the proper distance....

If you have a smallish screen... 50" say and view it from 3 metres then almost all that picture is within your central visual areas so that sharpness of BD might be appreciated even in the edges of the picture... but when you have a 100" cinescreen... and you are sitting 3 metres away... the edge of the picture is truly within your poorer peripheral vision and the sharpness there is "wasted" and if the equivalent upscaled DVD has enough detail in the transfer and the quality where you are looking then it doesn't really look too bad at all....

Anyhow... this is only my observations.... you're free to discuss them... but spare your nasty comments for something else...

The theory is OK, but a few factors come into play.

Human vision is rarely "static". The eye is always adjusting - in realtime - to stimulus, and then your brain interprets what it's seeing/sends messages back to the eye, which, in turn, sends impulses back the brain etc. etc. in an endless stimulus/response loop.

Given that film is in motion, it's a perpetual stream of new info.

The human eye can certainly focus on a specific area, and items in the periphery are less focused, but this is a gradual dropoff as you move further away from the focal point....but it's not this cut and dried, as alterations to the light/image (as is the case with film) cause constant readjustments/stimulus for the eye - thereby changing the focal point. Another factor is that humans don't focus on one point when watching film/in general - our eyes are constantly scanning/in motion.

With regard to the focal point, human vision has quite a wide range (of about 180 degrees). Sure, you can focus on a drop of dew on a leaf in a film....or you can focus on as much of the screen as possible. Typically, this would be around 120 degrees, if close to the image. There's a law of diminishing returns here as you get closer to the screen, and where it's not possible to view it entirely.

The comparison of the eye to a still (or film) camera is "theoretically" sound, but doesn't apply in the real world. Generally, in film, you'll see something that is sharply in focus - dependent on how the lens is pulled. As a simple test, go out to a park - and look at a tree that's close to you. You'll see that trees/grass/houses etc. in the background are not completely (or significantly) out of focus as they are in film/in a photo. They are much clearer/our field of vision is much wider.
The ability to perceive depth (in realtime) is where the eye/brain and camera lenses have little in common.

Remember, our vision is binocular (3D vision). A camera is only viewing the world with one eye (flat, or 2D).
Our perception of depth (on film or in the real world) comes down to how we translate light, shadow, specular highlights, etc.
High def video presents more of these/finer gradients of light/shade/colour etc. - resulting in more info to the eye/brain which "fools" us into perceiving greater depth (a more 3D image).
As such, HD video is more natural to the eye - because it more closely resembles our "real world" vision.

Having said that, you'd need an image of between 330-580 megapixels to perfectly mirror human vision at 90 and 120 degrees, respectively. At our full field of 180 degrees - even more.
The variance in pixel count is due to the actual lighting conditions/what you're looking at...there's lots more to see sitting in the Great Southern Stand at the AFL grand final than when sitting in a room with four white walls.

As such, 1920 x 1080 pixels is a LONG way from this....and DVD resolution is even further away.

Bottom line - if you like the quality of the image in your HT rig - don't think, just enjoy!

Harry Traquair (d. 1954) an Edinburgh ophthalmologist described the human visual field as "an island of vision or hill of vision surrounded by a sea of blindness".

While the sensitivity of the eye to light stimulus conforms to this 'hill of vision' (remembering it is a logarithmic slope) the drop in acuity is actually not gradual but rather precipitous so that reading of words immediately adjacent to the one you are reading becomes difficult rather quickly. If your central vision has acuity of 6/6 then you only need to go out 5 degrees before you're down to 6/12 and then outside of 10 degrees you're already down to 6/60 and outside that its lower than 6/60 or what is termed legally blind.

You can see this for yourself..... try looking at the frame of your monitor with one eye closed and try to read this paragraph.... In fact try reading a much larger text like the DTV FORUM title at the top of the page by looking at the bottom of your monitor with one eye shut....




http://www.opt.indiana.edu/riley/HomePage/...hics/image9.GIF

Again, this is talking about close-up vision of something that is static.
I have no doubt that human vision works this way when reading text on a page or screen - with one eye shut or otherwise.

I personallly prefer to view my films with both eyes open, further than a foot from the screen

Please note that I'm not discounting what you're saying/proposing....I'm just attempting to add to the discussion/present another POV/extra info.

So how do cross-eyed people get on ? It must be hell watching a movie.

C.M

This is a slight tangent but whenever I see a person with one eye one of my first thoughts is that they can't appreciate 3D movies.

Feel free to carry on with the topic of the thread now fellas.

I think oscwilde has probably said it more accurately, but the issue is that reading text across a page and watching a movie are different. The focus moves around the screen as we watch a movie and so the benefit of the whole picture being a higher quality is not lost.

+1 SDL ; the brains cognitive abilities shouldnt be discounted

http://knowledgerush.com/kr/encyclopedia/Phi_phenomenon/

Well it just goes to show that everything we see is just an illusion anyway.

C.M

Life is merely an illusion caused by a lack of drugs

I can't quite get my head around that one....


C.M

Well I give you credit phreek for trying to work out scientifically why you keep talking crazy

But seriously, could it be your viewing habits?

I mean blu-ray and dvd quality is variable. A poor blu-ray can look no better than a good dvd. Granted the blu-ray version should always look much better than the dvd version of the same film (ever compared the blu-ray to the dvd?), the sad fact is some films will always look, well, crapish. Now if you are watching an "average" to "poor" blu-ray and then you watch a "good" dvd, you may well feel there is little between the two. Likewise if you have had a little break from viewing discs and stick in a "good" dvd (after watching some digital tv) you again may feel there isn't much in it. But, if you watch a "good" blu-ray immediately followed by any quality of dvd, the difference is pretty bloody obvious.

Maybe it's all down to the way you watch things?

or maybe you're a troll

Phreek - given you are watching the same display for both bluray and scaled-dvd, and the amount/size of screen you can see clearly is the same for both formats. Watching the bluray version of any particular title (given a reasonable transfer) will be superiour to that of DVD, scaled or otherwise; ruling out the periphery you simply have more detail with bluray.

Again, i really dont see the point of your post other than to lay the foundations of a new bridge for people to argue over - the only debatable part of your post isnt related to bluray at all.

Bitey.

Quite an interesting and logical suggestion. On the other hand, if the screen is giving a viewing angle of less than 30° it is likely that even the macular part of human vision will not be getting the full benefit of the available resolution of Blu-ray. This effect of itself would tend to reduce the visible advantage of Blu-ray over upscaled DVD.

Another factor I find is that looking at a small screen (say 42") at a distance giving a 30° field of view is not the same viewing experience as looking at a larger screen (say 60") at 30° field of view.

I find a bigger screen is somehow easier to "take in" and "scan". This may have something to do with the difference in images between the two eyes being less the greater the viewing distance from the screen. The eyes/brain would not have to do as much work to merge the slightly different images from each eye into a single apparent image.

Well then, last week I had a trabeculectomy performed on my left eye. I used to have 6/4 acute vision in both eyes.

Whilst my vision may take up to 6 weeks to return to 6/6, I can tell you all that Blu ray still looks better than DVD full. Peripheral vision has nothing to do with detail.

Here is a piece from Wiki,

" Being fully aware of your peripheral vision allows you to focus on your entire field of vision instead of focusing on just one spot. This should enable you to notice small movements at the edge of your sight and so be more aware of your surroundings and ready to react to things other than those directly infront of you. "

Even with one eye

Cheers
Struggo