Impression of Depth and how to get it?

[jcuknz]

Lines stretching into the distance are very attractive to photographers but in good photographs they lead to something interesting rather simply in themselves leading to nothing.

[geoz]

There is also the concept of showing "space". Shallow DOF can look flat if the background doesn't doesn't contrast either in color or tone. Compare your 1st and 2nd shots which have about the same DOF. Similarly you can have a sharp shot but using foreground or perspective introduces space.

For example,



George

[AB26]

I believe there is clear differentiation between depth and DOF. It is two different things all together. DOF is used by photographers to isolate a subject from surrounding objects, though it can also be used very effectively to create a feeling of depth.

Depth is created by many contributing factors, like Bill said, like leading lines, perspective, DOF, haze, etc. Colin’s images demonstrate how depth is created by using leading lines.
An image with lots of depth should have a very distinct foreground, middle ground and distant background. It should not be the object of the photographer to “isolate” one specific subject in an image depicting depth perspective. The object should be to lead the viewers eye trough the image from foreground to distant background. In landscape photography we see lots of depth without using DOF control to create the feeling of depth.

Does any of the birdhouse shots depict depth? I do not think so, there is a subject and a background. The viewers eye is not led trough any of the images. DOF is not used to create depth, in this instance, but rather to isolate the main subject from the rest of the image.

Although the attached image was shot at the worse time of day I think it is not completely flat. Though the eye may be drawn to the big tree it is led trough the image by the narrowing road into the distance. Your eye should not be fixed on one main subject in the image but rather scan the image for other interesting objects.

[Didace]

Lines stretching into the distance are very attractive to photographers but in good photographs they lead to something interesting rather simply in themselves leading to nothing.

Sometimes, it's the nothing that is interesting.

[RobertsMx]

I think the original post is about a "3D pop" than leading lines, where the DoF is just enough (and the backdrop blurred just enough) to provide a clear separation. Here's another example that I feel fits the bill...

(Sony NEX-3,Contax-Zeiss 50mm Planar, at f/2)

[DanK]

While I agree that there is much more to the impression of depth than just DOF, I think one point about DOF not mentioned yet is important: DOF is not the same as background blur. Background blur is a function of focal length as well as DOF, given the same framing of the subject (i.e., the subject filling the same fraction of the frame). If you frame the same scene identically with two lenses set at the same aperture, the longer FL will provide more background blur because of its smaller FOV. (In essence, the longer lens spreads the background more to fit the frame because the narrower FOV captures less of the background.) The best discussion of this--complete with pairs of photos to make it concrete--is here: http://toothwalker.org/optics/dof.html.

[xpatUSA]

I think the original post is about a "3D pop" [rather] than leading lines, where the DoF is just enough (and the backdrop blurred just enough) to provide a clear separation. Here's another example that I feel fits the bill...

(Sony NEX-3,Contax-Zeiss 50mm Planar, at f/2)

Thanks, Manu, for an excellent example of what I was trying to say in the OP.

[rpcrowe]

The problems with your first birdhouse image (and to a degree with the second image) is that the birdhouse doesn't seem to be in focus and the bokeh is somewhat ragged and distracting.

In order for selective focus to give the impression of depth, the main subject needs to be in crisp focus to differentiate the subject from the background. The background can either be totally out of focus...



Or it can be just a bit out of focus like this image...



The bokeh produced by the lens you used for these images (I suspect that it might have been the Canon 50mm f/1.8 Mk-II or similar lens) was not smooth but, rather a collection of circular highlights. A creamy smooth bokeh attracts less attention than the ragged bokeh...



There are other ways to give the impression of depth, framing the image with an arch or foliage, using leading lines, and the diffusion of distant areas due to mist, fog or other impurities in the atmosphere...

Here is an example of framing an image...

[xpatUSA]

The problems with your first birdhouse image (and to a degree with the second image) is that the birdhouse doesn't seem to be in focus and the bokeh is somewhat ragged and distracting.

With all due respect for your excellent images, you may have missed the purpose of the admittedly poorly taken birdhouse shots. The point was to demonstrate that a subject shot with either too much or too little DOF will have a lesser impression of depth than one shot "just right". For each shot, I focused best I could on the roof corner nearest to the camera so as to emphasize the gradual (or not) change of acutance in the subject going away from the camera. The background was really not intended as part of the discussion which has indeed veered off into realms of bokeh separation, space, and such.

In order for selective focus to give the impression of depth, the main subject needs to be in crisp focus to differentiate the subject from the background.

This statement is contradictory to my original assertion. My third image shows that subjects that are entirely in "crisp focus" do not give an impression of depth of the subject. As opposed to Manu's chair shot which is sharp at the front edge of the seat.

[geoz]

With all due respect for your excellent images, you may have missed the purpose of the admittedly poorly taken birdhouse shots....

After rereading your initial post I finally think I got what you are after. So my first post missed the mark. Your first birdhouse shot illustrates best what you were trying to accomplish since the point of the roof is in focus. Then gradually out of focus into the background. However, IMHO, while it is an interesting effect I don't think it adds to a feeling of depth. In both the birdhouse and the chair it's lines that do. I think if you took a relative flat image and applied rings of decreasing clarity you would get a vignetting effect but not one of depth. Blurred background pictures are a bit like nearsightedness which if anything lessens depth perception. It was an interesting exercise and I learned a bit playing with Lightroom.

Best regards,
George

[xpatUSA]

After rereading your initial post I finally think I got what you are after. So my first post missed the mark.

Yes, George, my original description was pretty poor - almost as bad as the pics :-(

Your first birdhouse shot illustrates best what you were trying to accomplish since the point of the roof is in focus. Then gradually out of focus into the background.

The first shot was actually intended to show too much changing of focus over the depth of the subject - which IMHO detracts from the impression of depth - being not really how the eye and mind sees it. The gradual change you mention above was supposed to be in the second image.

The third image was, to an extent, misleading - I should have kept the background blurry (like the other two) while keeping the entire subject sharp all over, attempting to show in the third image that the subject itself has little impression of depth.

However, IMHO, while it is an interesting effect I don't think it adds to a feeling of depth.

Oh.

In both the birdhouse and the chair it's lines that do.

Hmmm . . . Manu (the Poster of the chair image) thought otherwise and so do I. Still, if I understand you correctly, the claim is that two identically framed subjects with identically blurred backgrounds - one subject sharp as a tack all over and one with the proposed very gradual de-focusing from front to back - would look identical in terms of impression of depth. That is to say, absolutely no impression of depth would be added by such a gradual de-focusing?

[geoz]

...the claim is that two identically framed subjects with identically blurred backgrounds - one subject sharp as a tack all over and one with the proposed very gradual de-focusing from front to back - would look identical in terms of impression of depth. That is to say, absolutely no impression of depth would be added by such a gradual de-focusing?

Hmm - sounds like a challenge

I don't have the lenses to try this with a camera but tried to duplicate the effect in Lightroom.

The picture was shot raw, no PP except for inserting gradual filters then reducing clarity and sharpness in each to the max. Three filters were inserted one on top of another to make the effect cumulative. The wall in the background is the same for both.

In the first they are staggered: at the top of the first desk, at the bottom of the third desk, and at the bottom of the wall.

In the second all the filters were moved to the bottom of the wall.





Thoughts?

[MrB]

The original question was, "...which one has the most realistic impression of depth, in your opinion?". I have not yet seen or read anything here to change my views:
1. Realistic depth perception has little or nothing to do with depth of field - in reality, as our eyes move through a scene, it is natural to see in sharp focus any part that we look at.
2. The clues indicating perspective in the scene (such as the apparent angles between parallel lines, and the apparent smaller sizes of distant objects, e.g. posts #22 and 23) contribute more or most to the realistic impression of depth.
These two points are clear to me in the images of the bird house (and very obvious to me in the image of the chair) - the depth is there in each image mainly because of point 2, but it is less realistic in images #1 and #2 (and the chair image) because of point 1.

These are, as requested, my opinions on the realistic impression of depth.

Philip

[pnodrog]

I agree with Andre (post #23 above). An impression of depth is mainly achieved by composition and perspective with lighting and atmospheric recession also contributing. The use of DOF is probably the least significant factor. DOF is used primarily (assuming there is a choice) to isolate and enhance the main subject matter.

e.g. In the classroom? photographs above the differing DOF has minimal effect on the feeling of depth in the scene.

[AB26]

Hi Ted,

Must thank you for this thread. It made me think a lot.

Depth is a perception created by the human mind. We see depth because the human eyes see things in 3D. A human with only one eye does not see 3D. I guess the one eyed ones see images as a two eyed human see a photograph. A friend of mine, with one eye, once said to me he cannot judge distance. You can only judge distance if you can see in 3D.

We do not see backgrounds as blurred when we look at objects in a distance. The background objects are only blurred when we concentrate on objects near us. When looking at objects far from us objects within a limited distance from us will be blurred, but only objects close to the eye.

To create the perception of depth in photography we might use DOF control to blur objects closer to the camera. When the background is blurred we do not perceive the scene as having any depth but rather to be “concentrating” on an object nearer to the eye. When objects nearer the camera are blurred and objects further away and into infinity are in focus the human brain will perceive that as having depth.

The best way to create a perception of depth in photography is by using wide angle lenses. The best of depth perception in photography is achieved with fish eye lenses. Something in the foreground has to be big and the further objects are from the foreground it should “narrow” down and get smaller into the distance. A blurred background does not create a perception of depth but rather isolation.

If you reshoot that birdhouse, using a wide angle lens, and get it out of focus but have the background in focus it will create more of a perception of depth. To have more of a depth perception you will need to add middle ground to the image.
In the chair shot “depth” perception would have been achieved if the chair was blurred and the eye was led to an in focus distant object. As the green chair is at the moment DOF control isolates it from the perception of depth.

The last image posted by Richard would have been a perfect example if the people in the foreground were a tad blurred and the arch gradually “lost” the blur with everything beyond the arch in focus.

The classroom is the exact opposite of creating a perception of depth.

[xpatUSA]

Some posts insist on discussing an entire scene while all my posts are trying to discuss the depth of a single object within a scene. I suppose a classic example is that of a single flower shot sideways close up with the traditional bokeh'd-out background. Some appear to be claiming that the said flower sharply in focus all over would have a greater impression of depth that one shot with a slight (very slight) decrease in focus toward the parts of the flower farthest from the camera.

I remain unconvinced. Sorry.

I'll get my coat . . .

[chauncey]

I'll get my coat . . .

Aah...it is so difficult trying to communicate with plebeians.

[AB26]

depth of a single object
I remain unconvinced. Sorry.

I'll get my coat . . .

OHO! Depth in a single object is attained by light, not DOF control.
Have you ever had a good look at a painting of a single object? Have you ever seen how an artist uses lines and shadows to get a perception of depth?

Only naughty boys throwing a tantrum when not getting their own way, get their coat!

EDIT:
PS. Photography is not AN art it is a craft. You need to see the light before you can turn the craft of Photography into art.

[pnodrog]

Aah...it is so difficult trying to communicate with plebeians.

It should be easy for a photographer to communicate with plebeians - after all cell phone photography is a plebeians main form of art (even exceeds tagging)

[geoz]

I remain unconvinced. Sorry.

I'll get my coat . . .

Definitely a fun exercise. In general I thing blurring the background in close ups brings what is sharp closer, so with other factors like tone and color it does add depth for this situation. The gradual fade in the chair picture works better than a narrow DOF but I don't think it adds depth. Similarly, I can't think of blurring the distance in a landscape to create depth.

Thanks,
George