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-   -   Two Shot Landscape Pano Using 600mm f/4 Lens (http://www.openphotographyforums.com/forums/showthread.php?t=18929)

Tom Robbins November 11th, 2014 12:48 PM

Two Shot Landscape Pano Using 600mm f/4 Lens
 
I recently went to a Nature Conservancy area where bison were recently introduced. The hope was to get some eyeball to eyeball views of the animals from a respectful distance. But, the old sunlight mojo wasn't working and the subjects stayed put in tall grass.

It seemed a total shame to haul the old Canon 600mm f/4 all that way without using it, so I played around a bit and wound up with an almost 1:2 aspect ratio pano from two horizontally shifted shots. The lens collar and Wimberley gimbal head made leveling things out pretty straightforward. The lens and camera was mounted near its center of gravity, which may have been somewhere near the nodal point.

Anyway, here's the weird result:


I was struck by a couple of things. First, the depth of field is remarkably shallow, even at the set aperture of f11. Second was the compression of the visual elements. The gravel road is fairly straight, but the slight wiggles and bends are greatly magnified here. The same effect is also seen as slight variations of terrain are turned into significant looking hills and dales.

Oh, the bison were hunkered down and out of sight in the grass at the left side of the frame. Crafty devils...

I'll keep the experience in mind, but right now I can't imagine a situation where this approach would be useful.

Asher Kelman November 11th, 2014 02:15 PM

Quote:

Originally Posted by Tom Robbins (Post 157374)
I recently went to a Nature Conservancy area where bison were recently introduced. The hope was to get some eyeball to eyeball views of the animals from a respectful distance. But, the old sunlight mojo wasn't working and the subjects stayed put in tall grass.

It seemed a total shame to haul the old Canon 600mm f/4 all that way without using it, so I played around a bit and wound up with an almost 1:2 aspect ratio pano from two horizontally shifted shots. The lens collar and Wimberley gimbal head made leveling things out pretty straightforward. The lens and camera was mounted near its center of gravity, which may have been somewhere near the nodal point.

Anyway, here's the weird result:


I was struck by a couple of things. First, the depth of field is remarkably shallow, even at the set aperture of f11. Second was the compression of the visual elements. The gravel road is fairly straight, but the slight wiggles and bends are greatly magnified here. The same effect is also seen as slight variations of terrain are turned into significant looking hills and dales.

Oh, the bison were hunkered down and out of sight in the grass at the left side of the frame. Crafty devils...

I'll keep the experience in mind, but right now I can't imagine a situation where this approach would be useful.


Tom,

The image is eye catching with the fields, trees, different textures and sienna colors.

To me the method you have chosen has the advantage of throwing gezillions of pixels over this choice area, that would otherwise be poorly rendered in a crop from a wider view.

I like your organic way for going at composition. The compression is an interesting idea. but does compression differ on in how many pixels are allocated to a certain region. If one took the same picture from the identical position with a 50mm of 14 mm lens, would the compression be any different. My guess it would be the same, with far less pixels but wider DOF.

IOW, isn't "compression" but another way of talking about perspective? Or am I mistaken here?

Tom Robbins November 12th, 2014 11:15 AM

Asher, that's an interesting question about compression of elements at long focal lengths compared with cropping an image made with a shorter focal length lens. I have to confess that I've no idea how this would play out, but suspect you're right. After all, magnification is magnification regardless if it is accomplished with optics or by simply moving physically closer to the subject. Perhaps Doug or someone else here can offer some insight.

Just to establish what the area looks like with a normal perspective, here's the same place seen in a photo taken a couple years ago during winter using a 45mm lens. The recent 600mm version was aimed at the area where the trees sort of curl over the top of the road.


Doug Kerr November 12th, 2014 12:41 PM

Hi, Tom,

Quote:

Originally Posted by Tom Robbins (Post 157388)
Asher, that's an interesting question about compression of elements at long focal lengths compared with cropping an image made with a shorter focal length lens. I have to confess that I've no idea how this would play out, but suspect you're right. After all, magnification is magnification regardless if it is accomplished with optics or by simply moving physically closer to the subject. Perhaps Doug or someone else here can offer some insight.

Indeed, the apparent "compression of distance" is wholly a result of the camera being a greater distance from the "nearest" of the objects of interest, as normally comes along with the use of a greater focal length lens. But it is not a property of the focal length.

If we shot from that same distant point with a "normal" focal length lens, the distant scene of interest would of course be smaller on the image, but if we examined it we would find it exhibited exactly the same "compression of distance" effect as we would get shooting from that point with the greater focal length lens.

If you in fact shot, from that greater distance, using a "normal" focal length lens, and then cropped out the same material as filled the frame when shooting from that same place with the greater focal length lens, the scene would look just the same (from the standpoint of "compression of distance").

It is, as Asher said, a matter of perspective - meaning where the camera is.

Best regards,

Doug

Doug Kerr November 12th, 2014 02:14 PM

To give a little more in sight into the geometric optics involved.

Imagine a "scene" consisting of two telephone poles both 40 feet high, 100 feet apart along the road.

If we shoot from a distance of 500 feet from the "nearest" pole, their relative heights on the image will be 600:500 (nearest: farthest) (that is, a ratio of 1.2:1). When we see that ratio (assuming that the too poles are of the same actual height), we instinctively associate that with a certain separation between the two poles.

If we shoot from a distance of 1000 feet from the "nearest" pole, their relative heights on the image will be 1100:1000 (nearest: farthest) (that is, a ratio of only 1.1:1). When we see that lower ratio, we associate that with a lesser separation between the two poles.

Note that I have not mentioned focal length.

Best regards,

Doug

Mike Shimwell November 12th, 2014 05:34 PM

Or pragmatically, where you stand determines perspective and lens choice/cropping determines field of view.

There's an old saying that there are only two variables - where you stan dand when you release the shutter!

Tom dinning November 12th, 2014 06:32 PM

Quote:

Originally Posted by Mike Shimwell (Post 157394)
Or pragmatically, where you stand determines perspective and lens choice/cropping determines field of view.

There's an old saying that there are only two variables - where you stan dand when you release the shutter!

If I was close enough, Mike, I'd kiss you. In a manly way. of course.

I like to add one more to the list. Who you are.
Bloody hell, that makes a difference.

Tom dinning November 12th, 2014 06:36 PM

Tom, it must be in the name. I do so much enjoy your photos, no less these. Compression or not, there is a beautiful mood presented here. You have transported me to Stone Barn Road and I will spend a few moments walking the dusty path.

Cheers
Tom

Bart_van_der_Wolf November 13th, 2014 01:17 AM

Quote:

Originally Posted by Doug Kerr (Post 157392)
To give a little more in sight into the geometric optics involved.

Imagine a "scene" consisting of two telephone poles both 40 feet high, 100 feet apart along the road.

If we shoot from a distance of 500 feet from the "nearest" pole, their relative heights on the image will be 600:500 (nearest: farthest) (that is, a ratio of 1.2:1). When we see that ratio (assuming that the too poles are of the same actual height), we instinctively associate that with a certain separation between the two poles.

If we shoot from a distance of 1000 feet from the "nearest" pole, their relative heights on the image will be 1100:1000 (nearest: farthest) (that is, a ratio of only 1.1:1). When we see that lower ratio, we associate that with a lesser separation between the two poles.

Note that I have not mentioned focal length.

Hi Doug,

Indeed, perspective is not determined by focal length, but by the scene viewpoint position.

However, there is a focal length aspect to the apparent perceptual compression that most discussions ignore/underestimate. It is the viewing distance of the captured output.

Geometric projection dictates that if we were to view the output from the identical distance as the shooting distance, perspective would be/look identical as well. Of course our output would need to be magnified to the same original proportions, otherwise we wouldn't be able to see it at a distance. So, with closer (output) viewing distances of that same scene, the output size should scale down proportionally to preserve the natural geometrical relationships between subject distances and sizes.

What happens in practice is, that with long focal lengths, we tend to magnify the output more than it should be (larger than the geometric projection would warrant), and/or view it from too close a distance to still respect projection geometry. That will lead to an apparent visual compression of perspective.

The simple geometric projection relationship between original subject size and output size is:
OutputViewingDistance = (OutputWidth / SubjectWidth) x SubjectDistance

That same (OutputWidth / SubjectWidth) magnification ratio applies to the focal length and output viewing distance, if we want to preserve the original perspective:
OutputViewingDistance = FocalLength / (OutputWidth / SubjectWidth)

When we deliberately choose a different (too close) output viewing distance, the apparent perspective will become "compressed". Obviously, the opposite happens with wide-angle lenses, and viewing from to far a distance.

Photographers can use that as a creative tool. In fact it is exactly what I like about longer focal lengths to shoot landscapes, it seemingly compresses the perspective, which allows to use a composition that benefits from that subjective abstraction. Since the longer focal length also has a narrower field-of-view, stitching offers a practical solution to expand that FOV.

Cheers,
Bart

Bart_van_der_Wolf November 13th, 2014 02:08 AM

Quote:

Originally Posted by Tom Robbins (Post 157374)
I recently went to a Nature Conservancy area where bison were recently introduced. The hope was to get some eyeball to eyeball views of the animals from a respectful distance. But, the old sunlight mojo wasn't working and the subjects stayed put in tall grass.

It seemed a total shame to haul the old Canon 600mm f/4 all that way without using it, so I played around a bit and wound up with an almost 1:2 aspect ratio pano from two horizontally shifted shots. The lens collar and Wimberley gimbal head made leveling things out pretty straightforward. The lens and camera was mounted near its center of gravity, which may have been somewhere near the nodal point.

Hi Tom,

Well done. Keeping an open mind and using some experimentation to defeat the physical limits of Field-of-View, can still produce interesting results, as you've shown here. It's the large distance that makes the displacement of the entrance pupil less critical, so it will even work with a Wimberley/gimbal setup (which aims to balance the center of gravity rather than align the entrance pupil with the center of rotation).

Quote:

I was struck by a couple of things. First, the depth of field is remarkably shallow, even at the set aperture of f11. Second was the compression of the visual elements. The gravel road is fairly straight, but the slight wiggles and bends are greatly magnified here. The same effect is also seen as slight variations of terrain are turned into significant looking hills and dales.
Yes, as discussed, there is an apparent compression of perspective due to disobeying the geometrical relationships. That can work very well creatively, once exploited deliberately.
The shallow DOF is just another law of physics (exacerbated visually because we lose the sense of relative distance due to the above), which can only be defeated by focus stacking.

Quote:

Oh, the bison were hunkered down and out of sight in the grass at the left side of the frame. Crafty devils...
And the more satisfaction when you do pull it off the next time. If it were that easy/predictable, it would be less satisfying as well.

Quote:

I'll keep the experience in mind, but right now I can't imagine a situation where this approach would be useful.
Besides the DOF, I find the apparent compression effect useful with nature that presents patches of contrasting color or sharp transitions in distance. The compression will turn that into more of a flattened patchwork of shapes/colors than into something with depth. It adds a level of abstraction that could work, but not for all subject matter. It's still the photographer who makes the composition.

Cheers,
Bart

Doug Kerr November 13th, 2014 08:37 AM

Hi, Bart,

Quote:

Originally Posted by Bart_van_der_Wolf (Post 157405)
Hi Doug,

Indeed, perspective is not determined by focal length, but by the scene viewpoint position.

However, there is a focal length aspect to the apparent perceptual compression that most discussions ignore/underestimate. It is the viewing distance of the captured output.
<snip>

An important point. Thanks for illuminating it.

Best regards,

Doug


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