Fisheye lenses in landscape photography

January 29, 2016  •  Leave a Comment

When I first became interested in photography in the late seventies and early eighties I immediately fell under the spell of fisheye lenses, fascinated by their strangely warped perspectives and astonishingly wide field of view. But at that time they were a rather specialist piece of kit – and as a student way beyond my budget. It was not until more than twenty years later that I finally fulfilled my teenage dream and purchased my first fisheye lens, a Nikon 10.5 DX for a D200, followed a couple of years later by the 15 mm Canon for my full-frame 5D Mk ii. But after becoming the proud owner of such an exotic lens, I soon came to realise that using a fisheye effectively is far harder than I had imagined: the novel effect of curved horizons and distorted perspective wears off rapidly and is far from sufficient on its own to make an interesting photo.
So how can fisheyes be used effectively and creatively in landscape photography? What kind of compositions work best? Although everyone will have to experiment for themselves and find what works for them, I can offer a few suggestions based on my own experience.

So what is a fisheye lens?

In terms of geometry, a photographic image is a planar, two-dimensional representation of spherically curved space. The issue is analogous to that of map-making, where the convexly curved surface of the earth is projected onto a flat two-dimensional surface. And just as cartographers use many different kinds of projections (Mercator, azimuthal, equirectangular, Gall-Peters, to mention just a few), so too lens manufacturers can adopt different mapping functions when they construct their lenses. For mid-range and long focal length lenses, the conversion of a spherical object to a flat image is not an issue because the area of object space captured by the lens is so small as to be a very close approximation to planarity. Where it does become problematic is with wide-angle and ultra-wide angle lenses – we are all familiar with the barrel distortion and skewed perspective typical of such lenses.
Broadly speaking, all photographic lenses fall into one of two different categories: rectilinear or fisheye. Although people sometimes think that the only difference between rectilinear wide-angle lenses and fisheyes lies in their focal length, this is not the case. Rectilinear and fisheye lenses have an entirely different construction and use different mapping functions. With rectilinear lenses, straight lines in the object plane remain as straight lines in the image. Angles, however, are not conserved, resulting in converging verticals and distorted perspective at the corners of the image. Most fisheye lenses on the other hand use what is called an equi-solid angle projection, which means that a solid angle on the spherical surface is maintained on the object plane. Angles are conserved, but straight lines are mapped as curves. Consequently, with a fisheye lens the only lines that remain straight are those passing through the centre of the frame. In other words, the horizon will only be straight if it is placed right in the centre of the frame, which in most cases is precisely where you don’t want it to be! If the horizon is in the lower half of the frame it will be curved upwards at the edges, in the upper half downwards. And although having an upwardly curved or concave horizon can create some interesting effects, I personally find downward or convex curvature to be more natural as it is more in keeping with our own sense of the real curvature of the earth.
In turn, fisheye lenses can be divided into two categories, circular and full-frame (not to be confused with full-frame and cropped sensor cameras!). In circular fisheyes the image is inscribed within the frame, creating a circular image with an empty space at the corners, the diameter of the circle corresponding to a 180° angle of view. In full-frame fisheyes, the frame fits inside the circular image and is therefore completely filled – like a normal wide-angle lens, just wider and curvier! The diagonal angle of view across the frame corresponds to the 180° diameter of the circular image.
Whereas circular fisheyes were popular in the past, I would say that full-frame fisheyes are much more useful for landscape photography today.

How can they be used?

The first and most obvious characteristic of fisheye lenses is their astonishingly wide angle of view. The diagonal field of view is up to 180°, compared to rectilinear wide-angle lenses which can reach a maximum view of around 140° (for example, the Canon 17-40 mm has a diagonal field of view of 104° at 17 mm). This gives them a unique ability to capture extremely wide views and convey an impression of space (not to mention a sense of vertigo when looking at your feet through the viewfinder!).
They are also ideal for fitting very tall objects in the frame, such as trees and high buildings (Photo 1), and do a great job at creating exceptionally wide views in restricted spaces (Photo 2). Although this kind of application is generally more useful in other areas of photography such as architecture, there are certain situations in landscape photography where it can be useful, such as canyons.

The second most obvious feature of fisheye lenses is the fact that they produce curved lines, most notably horizons. And although upward curving horizons may be interesting in some situations, it is normally preferable to position the horizon in the upper part of the frame to achieve convex curvature, reminiscent of the Little Prince on his asteroid (Photo 3).
But placing the horizon in the upper section of the frame of course means that there is more space for the foreground, and in the case of a fisheye the amount of foreground can be staggering. This means you have to search carefully for a strong foreground subject and try to get in as close as possible to fill the frame. Personally I find that foregrounds with a strong central subject and/or symmetry work particularly well (Photos 4 and 5). In this kind of shot it is also important to ensure that the camera is perfectly level so that the horizon is cut off at exactly the same point on both the right and left sides of the frame, otherwise the image will tend to look skewed.

Another interesting feature of fisheye lenses is the fact that they focus extremely close up (in the case of the Canon 15 mm, less than 20 cm from the sensor plane, or just 6 cm from the front of the lens) and offer outstanding depth of field. This makes them ideal for near-far compositions, allowing you to focus on a small foreground subject while maintaining an extremely wide-angle view and a potentially interesting background.

Distortion correction software

Although fisheye lenses have been around for a long time, what is perhaps their most interesting and useful application is in fact a relatively recent development: the use of computer software to partially or completely correct distortion, in other words convert them to rectilinear images. Many different programs are capable of doing this, including Photoshop (from CS2 upwards), DxO Optics Pro and the Photoshop plug-in Fisheye-Hemi. Curved horizons are miraculously straightened while maintaining the enormous field of view. The resultant image may be a panoramic (2:1 or more) or – by maintaining aspect ratio – a standard 3:2 (Photo 6 a, b, c). Although another obvious way of creating panoramas is to stitch together a number of images, the final image has a very different overall feel, the converted fisheye producing a dynamic sensation of wide open space and streaming diagonals that stitched panoramas are unable to convey.
The downside of rectification is the inevitable loss of quality at the edges and especially corners of the image where the pixels are stretched out and there is a high degree of interpolation. With high megapixel cameras this may not be a major problem, although I find that results tend to vary from image to image. Some images work reasonably well whereas others look awful at the corners, in which case you have no choice but to crop the edges and maintain a 3:2 aspect ratio. However, even with cropped edges the field of view is far wider than with a standard wide-angle lens, as should be clear from Photo 6b.
I would even go as far as saying that the majority of fisheye images can benefit from some degree of distortion correction even if you intend to retain the fisheye effect because the curves tend to be aesthetically more pleasing with a slightly smaller angle of curvature. The photos of Badwater and Dog Lake shown here both use a small degree of correction in DxO Optics Pro (around 60% compared to full correction at 82%) to achieve a gentler curve of the horizon.

One last thing to watch out for with fisheye lenses is the potentially enormous variations in lighting conditions within the frame due to the extremely wide angle of view. In particular, bright corners of the sky tend to creep into the frame and catch you unawares, so be sure to check the histogram and have the overexposure warning turned on. The fact that there’s no provision for fitting a front filter rules out the use of graduated filters, so I personally prefer to bracket exposures and merge in Photoshop.

Fisheye lenses are compact and light (my Canon EF 15 mm f/2.8 fisheye weighs in at 330 g) and fit easily in a kitbag or rucksack, going almost unnoticed until the perfect photo opportunity presents itself. And although a rectilinear will in most situations be a landscapers’ wide-angle lens of choice, a fisheye can also be a useful tool, offering scope for striking visual effects, stretching creativity and adding variety to a portfolio, especially when used in conjunction with distortion correction software.


Photos and captions

Photo 1
Fisheyes are ideal for fitting very tall objects in the frame, as in this photo of a dead pine in Yosemite National Park in California.
Nikon D200, 10.5 mm fisheye

Photo 2
The curved horizon created by a fisheye lens can give a powerful sensation of wide open space, as in this dawn photo of Badwater in Death Valley, California. In this case the fisheye effect has been partially corrected using DxO Optics Pro 6.5.5 to give a more gradual curve to the horizon and create a 2:1 panoramic image.
Nikon D200, 10.5 mm fisheye

Photo 3
Fisheyes are ideal for creating super-wide views in restricted spaces such as canyons, in this case the much-photographed Antelope Canyon near Page, Arizona.
Nikon D200, 10.5 mm fisheye, distortion corrected using DxO Optics Pro 6.5.5.

Photo 4
This dead tree in Dog Lake in Yosemite National Park, California is a typical example of a central subject with a strong, symmetric foreground that is particularly suited to a fisheye treatment.
Nikon D200, 10.5 mm fisheye, distortion partially corrected using DxO Optics Pro 6.5.5.

Photo 5
Fisheyes can be used both horizontally and vertically. This is another example of use with a strong central foreground subject.
Monument Valley, Utah.
Nikon D200, 10.5 mm fisheye, no correction


Photos 6 a, b, c
Examples of distortion correction
Photo 6a. Original.
Photo 6.b. After conversion with DxO Optics Pro 6.5.5, maintaining aspect ratio.
Photo 6c. Without maintaining aspect ratio.
Particularly in the case of such a widely photographed subject (the classic view of the Mittens from the parking lot in Monument Valley, Utah must be a strong candidate for the world’s most photographed landscape!), the use of a fisheye has the merit of providing a rather unusual wide-angle perspective.
Nikon D200, 10.5 mm fisheye

Photo 7
Horseshoe Bend, Arizona. Conversion with DxO Optics Pro 6.5.5, left and right edges cropped.
Nikon D200, 10.5 mm fisheye


Photo 8
The rhyolite hills of Landmannalaugar, Iceland, taken with a Canon 15 mm fisheye on a 5D Mk ii, distortion corrected using DxO Optics Pro 6.5.5.

Photo 9
The Viti thermal lake at the Askja volcano, Iceland, taken with a Canon 15 mm fisheye on a 5D Mk ii, distortion corrected using DxO Optics Pro 6.5.5.

 


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