Mein kleines Mondlicht,

Can anyone think of this as an acceptable architectural photograph? Pfaugh.

Plate 1. Would anyone actually consider this an acceptable architectural photograph? Pfaugh!

I am certain that You have frequently seen photographs, both in print and on screen, that feature dreadfully distorted buildings. These images have become quite common, even in quality publications, in spite of the inherent ugliness that comes with the skewing of the perspective into unnatural angles. Natheless, such distortions are simply unacceptable in professional work. Whilst there are indeed times when it is simply not possible to obtain a clean photograph of a building, especially if the edifice happens to be a very tall one, there are always a number of things a photographer can do so that, in spite of the challenging conditions facing him, his photographs fulfil one of the chief goals of architectural photography: presenting the architecture in the most flattering way possible; and in order to accomplish this end, perspective must be maintained within a natural-looking context. It is of these ways, thus, that I want to tell You in this epistle.

However, before delving into the matters of perspective here explicated, let us consider perspective itself.

Photography turns a tridimensional subject or space into a two-dimensional depiction of it. The laws of perspective govern this conversion, and thus represent the effect of the subject’s space and depth in a bidimensional plane. Perspective is fundamentally the projection of space onto a flat surface. Photographs follow the rules of central projection (a.k.a. vanishing point projection), thus preserving the natural perception to which our eyes are accustomed[1]Adrian Schulz, Architectural Photography: Composition, Capture, and Digital Image Processing (Santa Barbara: Rocky Nook, 2009) 54 .

Perspective is determined by the position of the camera; as a result, if the camera is moved the spatial relationships within the picture will change. If You remember only a couple of concepts from this epistle, Mondchen, make sure this is one of them.

Of all the photographic genres, it is architectural photography the one in which geometric shapes are most paramount; thus, perspective vanishing points have great significance and need to be carefully considered when framing a photograph. Whenever parallel lines in a tridimensional space extend into the distance, a photograph will render them as intersecting on a defined vanishing point. If the camera is level with the horizon, all truly vertical lines will remain so in the picture. This is a fundamental principle of photography, and a tenet of architectural photography.

Thus, the general rule when approaching architecture is this: Keep the camera axis level with the horizon. The wider the lens used, the most crucial this rule becomes, and the most horrid the results if one deviates from it. When the camera axis is level with the horizon, the plane of the sensor is parallel with a building’s façade and the vertical lines will not converge, but shall remain, well, vertical. Tilting the camera will introduce an extra vanishing point and the verticality will become diagonality, introducing a keystone effect that will be more pronounced the more the camera is tilted. You can clearly see this in Plate 1: the excuse there being that keeping the camera level with the horizon would have cropped out most of the building due to the shooting position being at street level.

This is quite a conundrum, because most of the times the only level a photographer can shoot from is that of the ground. What to do then if the verticals must remain vertical?

 

Pixel pushing

One ‘solution’ is to use software to try to correct the distortions. This is not much of a solution, though, for a number of reasons; but before I list them, please look at the following pictures.

Image 2. A shot taken with the camera level to the horizon.

Plate 2. A shot taken with the camera level to the horizon.

Image 3. Tilting the camera introduces an undesirable keystone effect.

Plate 3. Tilting the camera introduces an undesirable keystone effect.

In Plate 2, Keeping the camera level to the horizon yields proper perspective and no converging verticals, but the steeple of the church has been cropped out and there is way too much negative dead space in the foreground. A solution would be to shoot from a higher vantage point, but in this case there wasn’t any and I was forced to shoot from street level.

Image 4. The software solution for perspective correction: simply not quite there.

Plate 4. The software solution for perspective correction: simply not quite there.

Since I was shooting with a standard zoom lens without perspective control capabilities, the only option was to tilt the camera upwards if I was to include the full building in the frame; this resulted in the unprepossessing keystone effect You can see in Plate 3. It’ll be up to the editing software (Adobe Lightroom in this case) to ‘eliminate’ the distortion and produce a picture without converging verticals. Sounds like a plan, but as You can see in Plate 4, the compromises of such a ‘solution’ far outweight its benefits.

In fact, not only has the steeple been cropped again, but closer examination reveals vertical lines that are not quite so. Nitpicking? Maybe I am. However, the main problem is even less obvious so far, but it will become evident when the picture is sent to the next step of the production workflow: namely, a lot of pixels have been discarded. Thrown out. Gone! The image quality of the file has been axed worse than the steeple in the photo.

Loss of image quality may not be so detrimental for images destined for the Web, where small sizes and low resolutions are still widely used, but for printing purposes and —gasp!— enlargements, a file so heavily manipulated digitally  is nigh unusable.

Furthermore, too much digital straightening can introduce intolerable optical strain in the picture when the apparent viewpoint conflicts with other perspective clues. Pushing on one end inevitably causes a pull on the opposite one, and You can see how the steeple now looks larger and more looming than it is in reality. It almost looks inflated, like a hot-air balloon of unconventional shape: one almost expects the church to be lifted off the ground and take to the Heavens any moment.

What to do then?

 

Using the foot zoom

Well, another partial solution is to step back and make a photograph in portrait orientation so as to include the whole building with a minimum or a complete lack of converging verticals. Such a photo, however, will have a lot (and I mean a lot, as in practically half the image) of dead space in the lower part of the frame that will have to be cropped out in post-processing.

Mackenzie Art Gallery

Plate 5. The only way to fit the lamps in the frame was to use a portrait orientation. Doing so yields a vast amount of negative space in the image.

Plate 6. In this case, cropping out half of the picture works, and the high resolution of the camera helps the photographer end up with an image with enough pixel density for proper (but not too large) printing.

Whilst this is a useful work-around that can yield excellent pictures, this is yet far from the most satisfactory solution: we are still throwing away roughly half the pixels, and whilst we may retain enough quality for the photograph to be printed sans pixelation in a magazine, large sizes such as wall prints can be impossible to render with good detail; plus, what if we’re already back against a wall, or a busy freeway, or a cliff, or a rabid cat ready to pounce? Furthermore, this approach would also change the proportions of the frame, mind You. Oh, and let us never forget that perspective in a picture is determined by the camera position; thus, stepping back can throw everything out of whack. Heh, I rhymed.

Plate 7. Using a perspective control lens includes the whole building in the frame and all verticals remain so. (24mm, 1/60 sec @ f/16, ISO 200)

 

A-righting

The best approach is, thus, to use a lens with perspective control capabilities, such as the Canon TS-E 24mm f/3.5 L II, which is what was done for Plate 7. Now all things and lines are in their proper places, as God would have it.

So, a bloke has only to shell out the dough for the tilt-shift lens and alles gute?

No, not quite.

Plate 8. Inverse keystone effect, resulting from the camera not being level with the horizon, even though the lines of the focusing screen were matched with the lines of the church.

You see, Liebchen, even with such a lens, if the camera’s axis is not level with the horizon the photographer will still get the dreaded keystone effect, as I did in Plate 8, in which the steeple seems to lean forward and be thicker at the top than it is at the bottom.

This is one of those things that are extremely difficult to eyeball, and even with a grid-type precision focusing screen that allows one to align the camera precisely with the lines of buildings, a man can still end up with converging verticals as the horizontal lines of the buildings are not always level with the horizon due to the topography of the locale. Moreover, a building’s vertical lines are not always perpendicular to the horizon or even parallel to other verticals in the same edifice!

Enter the humble spirit level.

No, I am not referring to the bubble level on the tripod or the one on the tripod head or the camera plate. These are not really reliable, with the latter being just partially useful and the former essentially useless as, again, being level with the ground does not necessarily imply being level with the horizon. I was essentially level with the ground when taking Plate 8, yet I still ended up with a distorted building. No, I am talking about a hot-shoe-type, 2- or 3-way spirit level.

Plate 9. A Kaiser 2-way hot shoe spirit level: a must when perspective matters.

Placed on the camera’s hot shoe, a spirit level makes it possible to align the camera with the horizon easily . Combined with a ’tilt-shift’ lens they run circles around the dynamic duo when it comes to righting wrongs… wrong verticals, I mean, and even other lines for good measure. I am even tempted to term the PC lens/2-way spirit level combination the dynamic duo of perspective, but perspective actually requires a dynamic trio, because work so precise unavoidably necessitates a sturdy and stable tripod. In fact, expanding on this rather silly super-heroes allusion, a fantastic quartet is required, for when it comes to getting the best results with a minimum of hassle, a geared tripod head is unmatched.

 

Taking the right approach

The realm of theory is mainly a realm of ideals; ideal subjects, ideal conditions, ideal approaches. The province of the praxis is often quite different, less a photographic paradise and more a rugged land where contingency is the best aide-de-camp.

Ideally, I would have my dynamic quartet readily available at all times. Alas, there are occasions that surprise me with only the camera with the PC lens on and nothing else. Plate 10 was taken in one of those occasions. Yet, I managed to record an image that required little straightening in post-processing thanks to practice, a steady hand (failing that, a fast shutter speed 😉 ), and a precision focusing screen. It was all a matter of composing, metering, shifting the lens and shooting.

An intermezzo: particularities of PC lenses

Speaking of metering, if one is using a PC lens and not using a hand-held meter (i.e. relying on the camera’s through-the-lens reflective meter), one must meter before doing any shifting (or tilting for that matter). The exposure settings that the camera reports when the lens is in any position but its default, centred, zeroed one will be incorrect. This is why a hand-held meter with a 1° spot meter or attachment is invaluable; but again, it’s the land of the praxis and sometimes the photographer is forced to use the less than ideal through-the-lens metering.

One other thing: as the lens is shifted, light falloff begins to creep in. This, unilateral vignette can be as much as 1 stop darker than the metered exposure values, so one has to make sure to compensate for it. (Although, such ‘vignette’ can end up being useful, providing an impromptu ND grad to tame the bright sky into much needed underexposure.)

Plate 10. An acceptable rendition of the building, thanks to correct perspective.

Plate 10. An acceptable rendition of the building, thanks to correct perspective.

Likewise, there have been other times when I’ve had little choice but to resort to using a longer lens and shooting from farther away, or cropping off a large portion of the frame, or relying on pixel pushing. As usual, the determinant (or limitant) of my approaches is the eternal question What do I want? from a given photograph. In professional work, said question is often answered beforehand by the client and/or the assignment’s brief, which outlines not only the required looks and suggested angles, but also the final output (as said above, a photograph that will be printed has less latitude in terms of pixels that can be thrown out than an image that will be used on the Web).

 

Skewed up

And, yes, there are times and situations when a skewed perspective is the best way to get our message across. After all, there exists this excellent thing called Creative Freedom. But freedom is not a licence for chaos, and the bending of a given set of rules is in itself ruled by another set of rules. In simple terms, there are (at least) two rules regulating our straying away from a right and proper perspective that demands the verticality of verticals:

  1. The photographer has to have good reason for allowing the lines to converge, and,
  2. his intentionality must be made perfectly obvious.

Plate 11. Verticals converging and pointing heavenwards were essential in order for this image to successfully evoke an uplifting feeling.

When these rules are bent or broken, the resulting photograph will be seen as a mistake and the message one tries to convey, or the impact one wants to make, will be muddled or lost. Plate 11 shews the same building portrayed in Plate 1, but the effect made by the different angle used, by purposely leaving out the bottom part of the building, by shooting right next to the edifice is quite dissimilar even though the perspective remains skewed. Likewise, the photograph of the effigy of Frederick W Hill, follows the two rules stated above, and if there remained any doubts as to the intentionality of framing and composition, these are presently dispelled by my tilting the camera so that the head of the statue and the reflected twin tower opposite pointed towards the upper left corner of the frame. A viewer might not consider Plate 12 an excellent photograph, but he will certainly not see it as a mistake.

So, yea, at the end of the day the very thing we set out to combat, turns out to be the last tool in the box. Irony being another denizen of the rugged province of the praxis, this is hardly surprising; and it is hardly worth it to get oneself worked up about it.

Plate 12. Without the converging verticals and the tilted angle, this would have been at best a ‘meh’ photograph.

All I can tell You is that, like any other tool, it must be used with care, finesse, style, and when it is really suited for the task at hand.

At the end of the(our) day(s), creative freedom will not be valid as a justification for the sloppiness of our techniques, the slovenliness of our work, or the miserliness that will not let us procure the tools that our professional work demands.

And it is that thought, Mondchen, that I want to leave You as I close the toolbox and this epistle, but not without remaining,

Ever Yours.

 


To know more:

^^1. Adrian Schulz, Architectural Photography: Composition, Capture, and Digital Image Processing (Santa Barbara: Rocky Nook, 2009) 54.
2. Norman McGrath, Architectural Photography: Professional Techniques for Shooting Interior and Exterior Spaces (New York: Amphoto Books, 2009)