GRAPHIC TIPS & NEWS

Adapted from Practical HDRI: High Dynamic Range Imaging for Photographers (Rocky Nook)

By Jack Howard

Dateline: October 24, 2008
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The beauty of SLR photography is the ability to swap optics as often as you like for many different photographic feelings and situations. Certain lens types truly lend themselves to High Dynamic Range Imaging. Here are some breed-specific tips for making the most of your glass for High Dynamic Range Imaging.
Rectilinear Wide-Angle Lenses

Rectilinear wide-angle lenses are very popular for landscape and cityscape photography, and the same holds true in High Dynamic Range Imaging. The expansive field of view combined with the virtually unlimited depth of field when stopped down at hyperfocal distance can make sweeping vistas that envelop the viewer. Think about lines such as a country roadway, a meandering river, or the strong architectural details of a skyscraper, which can be employed to really pull the viewer into the details of the image.

The apparent magnification and close focusing can spotlight a particular foreground element in its environmental context, from wide to medium apertures. Whether it’s a desert plant on a rolling hill or a chef in his kitchen, an off-center foreground-intensive composition can have big impact.

Ultra wide-angle lenses can capture expansive views, and can keep a lot in focus from near to far, even at medium apertures. This source image was shot at f/5.6.


Rectilinear wide-angle lenses keep straight lines straight (or near-straight), but the expansive angle of view gives the keystone/vanishing point effect to lines that are not parallel to the sensor plane. This is particularly effected and effective as a compositional element with manmade, right-angled constructions. Make sure that one of the axes is plumb with the sensor plane—for example, when shooting up at a skyscraper, make sure the horizontal lines of the ascending stories are parallel with the top and bottom of the frame. When shooting a long structure, such as a train on a straightaway, make sure that the vertical lines of the train are parallel with the sides of the frame.

Stopping down to f/8 softens the rolling dunes behind this desert plant, but close focusing allows for the plant to be the main focus.

Two Flavors of Fisheyes

Fisheye lenses let the idea of rectilinear correction go out the window, warping straight lines into bowed curves, with the effect becoming most extreme the farther you get from the center of the image. Full-frame fisheyes matched to a particular sensor size will take in up to 180 degrees along the wide axis. Circular fisheyes capture a round image in the center of the frame that usually covers 180 degrees. Some photographers enjoy the warped perspective of these extreme images as-is; but there’s a whole subculture of photographers remapping fisheye images into rectilinear projections and computer video virtual reality (VR) environments. VR remapping, even when combined with HDRI is a little outside the scope of this book, but HDRI plus VR mapping can offer a richness of detail and luminance experience lacking in single-shot VR movies.

When you cannot eradicate keystoning, use it as an element to imply distance and scale. And be sure to keep one of the axes parallel with the edges of the frame! (And there’s a very real chance you may run into Seetharaman Narayanan on the 16th floor when he’s in town!)


Both fisheye flavors can usually close-focus to within a couple of inches (if not closer) and have very deep depth of field even at wider apertures—meaning almost everything from near to far in the immense angle of view can be acceptably sharp when focused properly. Use your camera’s depth of field preview (or simply take a test shot) to determine depth of field range. Be aware of the extreme “dog nose” effect with fisheyes, which can be used creatively to amplify the importance of objects very near the lens, but which can also be very unflattering to human subjects.

This 10 mm full-frame fisheye image shows the bowing effects of a fisheye lens, along with warped keystoning. Notice how prominent the Fish and Chips sign is in the foreground, due to my proximity to the sign during capture.

Swinging, Bending Optics

Big, Expensive, Perspective-Fixing Lenses
There are only a handful of these perspective-controlling optics available for DSLRs, and they are universally expensive. These bulky lenses usually communicate with the camera to set aperture and support in-camera metering, but they are shifted and focused manually. The primary purpose of this breed of specialized lens is to allow for focal plane shifts off parallel from the sensor plane to correct for keystoning and other quirks of optical physics that manifest in captured images when it is not possible to take the picture from a location that would present a more truly utilitarian, representational rendition of the scene.

Keystoning: Keystoning is a type of distortion that results when the film or sensor plane is not parallel to the subject's vertical surface (such as a tall building) when the exposure is made. The parallel vertical lines on this surface will no longer appear parallel but will appear to converge towards the top of the image. The resulting shape (a horizontal trapezoid) resembles the keystone at the top of an arch. This effect may be desired or it may be corrected with specialized cameras or lenses or during post-processing.

Employing a 24 mm tilt/shift lens, I was able to correct for keystoning in the steeple of the same church as seen in the fisheye image. Notice how much less prominent the Fish and Chips sign is, because I had to move my shooting position back several yards to take in the whole church with the longer, non-fisheye lens.


In plain English: tilt/shift lenses not only keep straight lines straight, but can be employed to keep right angles at or near right angles when photographing architecture under many conditions where keystoning will occur with a lens that cannot shift the focal plane.

Architectural shots are usually captured at small apertures, so that there is sufficient depth of field to keep the entire structure in focus; however, opening a tilt/shift wide while skewing the focal plane gives a zone of sharp focus that can wander across the image, from near to far. This can give an interesting perspective to rooftop photography, for example. And in the studio, this non-parallel focal plane can be exploited to pull the viewer’s eye right to the most important details of a product.

In this aerial view of Paris, a tilt/shift lens was used to both level the horizon and add a meandering focal plane across the middle ground.

A More Economical and Super-Fun Way to Mess Around with Focal Plane Shift and Curved Field Lenses

Lensbabies are fun little lenses that can be pushed, pulled, bent, swung, and shifted around a curved-field “sweet spot”. The introduction of the locking Lensbaby 3G opened up a whole new world of Lensbaby imaging including HDRI. Lensbabies feature magnetic aperture disks that sit in front of the lens element, and in addition to the normal circles, Lensbabies offers pre-cut shapes such as stars and hearts (as well as blanks for your own custom shapes) that will turn specular highlights off the focal plane into those cool creative aperture shapes. These “toy” lenses are starting to have a major impact in the world of photography and cinematography, and can make some interesting HDR compositions. Add the fact that a Lensbaby 3G will only cost a couple of hundred bucks, instead of thousands for a brand-name tilt/shift lens, and it’s a way to bend your focus without breaking the bank.

The Lensbaby 3G has a curved “sweet spot” and a locking mechanism, allowing for creative blur effects.

Macros: Make the Little World as Big as All Get-Out!

If budget allows, invest in a prime macro with 1:1 magnification and a fast maximum aperture. If not, many zoom lenses offer a “macro” setting which will close focus and give decent magnification, maybe up to 1:2; but if the macro bug really bites you, you’ll want to upgrade to a prime 1:1 as soon as possible!

Magnification of 1:1 means that an object that is 1 cm wide will be recorded as 1 centimeter wide on the camera sensor—when the camera is focused at its 1:1 focal distance. Changing the focal distance of a macro lens also changes the magnification of the lens. So, to keep your magnification constant at 1:1 (or any magnification), either the camera or the subject is moved until focus is achieved.

Bracketing several exposures of this tabletop composition of jewelry shows deep sparkle in the gems and very few hotspots on the shiny surfaces.


Magnification of 1:2 means that a 1 cm wide object will be recorded as 1/2 cm on the sensor. Magnification of 1:3 will record a 1 cm object as 333 mm. And, magnification of 5:1 will record that 1-cm object across 5 cms of the sensor. Even stopped down, depth of field is extremely shallow in macro photography, and the slightest camera movements will be amplified. If you’re thinking of combining HDRI and macro, a steady tripod is a must!

High Dynamic Range Imaging techniques can be very useful for macro photography when specialized macro ringlights or dual-head strobes aren’t feasible, practical, or within the budget. But when it comes to small, shiny objects, you’re actually sometimes better off using a longer telephoto lens zoomed in as close as you can. Yes, you sacrifice some absolute magnification, but the reflections of the tripod and camera aren’t nearly as prominent when the object is farther from the camera.
Normal and Telephoto Lenses—Both Zooms and Primes

Midrange lenses and long lenses, both primes and zooms, can be used in the field for portraits, wildlife, details of flowers, or to gain more reach to capture distant buildings or landscape elements. At wide apertures, medium zooms and telephoto zooms offer shallow depth of field and wonderful background separation, which can really make a subject pop from the background. Conversely, longer telephoto lenses appear to compress distances when stopped down to smaller apertures. Longer lenses amplify camera movements, so a sturdy tripod is very much advised for any HDRI attempts with telephoto glass.