PDA

View Full Version : Field of view



Gary Holliday
06-01-2007, 09:18 PM
I've always wondered if human vision has a natural format? What is our field of view?

And how does this fit into the format of prints that we make. Does a 16:9 widescreen photograph appear natural to the eye. Or perhaps a square image?

Pinholemaster
06-01-2007, 09:51 PM
All depends on how wide apart a person's eyes are, or if they only see with one eye. Each person is different.

Vaughn
06-01-2007, 09:57 PM
I think the problem of approaching this by determing the technical data of our eyes is that our perception differs greatly from what we actually see.

For example, we have a limited depth of field...but because our brains registers sight on a continous basis, we do notice few DoF problems. Our focus constantly shifts and our brains creates a flowing image of the world that is all in focus.

Same for field of view...our eyes constantly scan our surroundings, creating a far larger field of view than we get at any instantaneous moment.

Persistance of our memory of vision maintains a continous mental picture of our surroundings. I am staring at the computer screen, but what is surounding me at the edges of my sight remains as part of my visual perceptions.

I made a 360 degree image using a rotating 120 camera -- printed it out. Very confusing...I could see the image, but I could not wrap my mind around it, so to speak. Thinking in 360 degrees is a whole different story -- I don't think our brains, without a lot of training, can handle it.

Vaughn

Maris
06-01-2007, 10:24 PM
I think it was Fred Picker who said that all landscape photographs should be horizontal rectangles because God made people's eyes side by side not one above the other.

The wide aspect ratios like 16:9 seem in practice to be strongly associated with cinema or its home TV/computer incarnations. A while ago I did an informal census of all formats, all media presented to human eyes and by far the most prevalent was "A" format with A4 vertical the commonest size.

AgX
06-01-2007, 10:47 PM
Also think of the fact that the resolution of our retina is not evenly spread. There is only a small angle of view with highest acuity.

Thus we have two imaging devices lying horizontally next to each other, constantly focussing and swinging and tilting and the yielded images `somehow´ overlapping.

DrPablo
06-01-2007, 10:58 PM
I don't have the numbers in front of me, but visual field testing is a pretty standard neurologic exam. The bedside test is you have the patient stare straight ahead, then have them identify motion in the periphery. This is used diagnostically for visual field defects. There are more formal "perimetry" testing procedures that include brainstem evoked potentials.

The thing is, this is not really analagous to the field of view of a camera lens. One reason was mentioned, that being rapid saccades or eye movements that dart around to take stuff in, also (as mentioned) getting around issues of DOF.

The other reason is that the field of view covered by our fovea, which is the area of high visual acuity, is extremely small compared with the field of view of our entire retina. In other words, we have a very small field of view that is sharp, but a much larger field of view that is much lower acuity.

This is not a DOF issue, not an optical phenomenon -- it's a neurologic issue in that our retinas, our optic nerves, and everything all the way back to our occipital cortex concentrates attention and resolution on a small area.

Birds of prey have tiny tiny fields of view, but extremely dense photoreceptors -- thus they have incredible acuity, and can resolve things a mile or two away, or see a mouse on the ground as they're darting around a hundred feet in the air.

Edit -- Agx beat me to it.

AgX
06-02-2007, 02:08 AM
I don’t intend to beat anyone…

But Maris brought up one interesting aspect.:
Though that Fred Picker quotation seems quite convincing, we are sorrounded by A-verticals.

But why is film horizontal? Why is my computer screen horizontal, and can’t I write decently a letter on it?

I never thought a lot about this, but it could be interesting to look back into history how all these aspect ratios (especially including that vertical/horizontal issue) evolved in man’s cultural development (or movement…) over all kind of outings: painting, printing, photographing, filming etc.

phaedrus
06-02-2007, 02:13 AM
We have a sharp central area of vision of at most 3 degrees and a centrifugally increasingly unsharp field of vision of more than 180 degrees. Eye motion tracking studies have shown that we quickly scan a scene before us with that central sharp portion, with returning emphasis given to points of interest. It is assumed that during that scanning an internal image of our surroundings forms.

Gary Holliday
06-02-2007, 06:31 AM
I think my brain did a defragmentation of the hard drive overnight. I woke up remembering something about how the Greeks had come up with a mathematical view on this subject. I believe the 35mm format was a "natural" format. Can anyone shed some light on this?

I would like to print photographs in a format that fits in with our field of view. Believing that someone at an exhibition looking at the image would feel comfortable with it on a subconscious level.

bdial
06-02-2007, 07:08 AM
It's called the golden rectangle which has a ratio of 1:1.618 according to wikipedia http://en.wikipedia.org/wiki/Golden_rectangle. 35 mm is close at 1:1.5
I don't know that it has much to do with our natural field of view though, but we do find it pleasing for some reason. It's also present in a lot of natural proportions, which may be the reason we like it.

Nick Zentena
06-02-2007, 07:17 AM
But why is film horizontal? Why is my computer screen horizontal, and can’t I write decently a letter on it?
.

Because you bought a screen like that :p They used to make screens that were setup like a written page. Plus bigger ones more like a two pages side by side. Because of the cost [both the monitor and the desk space for the bigger models] most people didn't buy them.

Moopheus
06-04-2007, 08:43 AM
They used to make screens that were setup like a written page.

I had one of those a long time ago, specifically for doing typesetting work. It was great being able to see a whole page at a glance. Of course, with today's computers, many LCD monitors can be easily rotated to be used vertically if you desire, even though most people don't do it.

For books and magazines, the vertical format is just easier from a production and handling point of view; horizontal books are harder to hold. Books have been made that way since the invention of the codex. For art that's hung on a wall, I suppose that's not so much of an issue.

Helen B
06-04-2007, 11:48 AM
John Logie Baird adopted a portrait format for the first video recordings (late 20's) and broadcast television (early 30's).

Best,
Helen

Roger Hicks
06-04-2007, 02:41 PM
What's a 'natural' field of view?

Do you make postcard-sized prints and look at them from (a) 6 in/15cm or (b) 12 in/30cm; or 12x16 inch/30x40cm prints and view them from (a) 12 in/30cm (b) 24 in/60cm or (c) 36 in/90cm?

Consider the angle subtended by the subject, at the eye, at the time of taking, and the angle subtended at the time of viewing the print. When the two match reasonably closely there is a particularly three-dimensional effect.

Cheers,

R.

David A. Goldfarb
06-04-2007, 03:11 PM
Why is my computer screen horizontal, and can’t I write decently a letter on it?

Clearly the people who do spreadsheets have more power than the people who write letters.

Our department secretary has a screen that rotates, and she seems to leave it in vertical mode.

There are a few cameras that are natively vertical, like the Bronica 645 RF and the Linhof 220 (there was a horizontal version, but it's much rarer than the vertical one), and I'd suspect some of the long roll portrait cameras.

copake_ham
06-04-2007, 06:52 PM
Clearly the people who do spreadsheets have more power than the people who write letters.
.....

Interesting observation, David. And probably more correct than not!

I work in finance but a few years ago moved from the analytical side to the legal documentation. I now find it more frustrating working from a monitor since, as you note, it favors spreadsheets over text!

Alas, being a lowly attorney, I do not have the clout of an Admin Asst. to insist on a rotatable screen. Heck, in our shop, I'm happy if the damned system doesn't crash!

BTW: I do find, in 35mm format, I prefer the vertical with, of course, the exception of the standard landscape shot.

jd callow
06-04-2007, 07:06 PM
A relatively cheap video card will allow you to choose the orientation of the screen, the screen itself needn't have a rotation feature. Simply get one of the cards (I think most any nVidia card from a 7600GS up will do it) and mount the montor sideways.

copake_ham
06-04-2007, 08:17 PM
A relatively cheap video card will allow you to choose the orientation of the screen, the screen itself needn't have a rotation feature. Simply get one of the cards (I think most any nVidia card from a 7600GS up will do it) and mount the montor sideways.

Ah, JD, I see you do not work in the corporate world domintated by IT security!

To introduce anything into your computer at work - even putting a CD into the slot or attaching a data stick - is grounds for employment termination!

Great idea for freelancers and consultants, however. ;)

jd callow
06-05-2007, 12:15 AM
I am all too aware of the strictures of corporate weaseldom having been a weasel of the boogle once and possibly always.