Thin Lens: photos

Writing and photos by Abraham Neben

Cliffs in East Rock Park, New Haven

Fall colors shine on the dreariest days. Indeed nature photographers love cloudy days for the same reason portrait photographers use light diffusers. Clouds produce a warmer, softer light than direct sunlight, making reds, greens, and yellows pop, and lighting up nooks and crannies everywhere in the image. I took this photo last weekend in East Rock Park in New Haven after a half hour walk in the rain along Mill River, wishing I'd worn gloves. I really liked this view of one of the ridges with the new fall colors blooming up from the bottom of the frame.

Below is the google street view image of this scene

St. Michael's Church, Wooster Square Park

A photograph is made of many things. Shapes, colors, patterns, and textures in an image can work in harmony to create a scene that really pops, or they can confuse  the viewer with an uninteresting mishmash. Sometimes a color or texture can detract from an interesting shape or pattern. Exposing the scene to create a silhouette is a helpful trick here, especially when it creates some mystery!

Below is the google street view image of this scene.

How I learned to stop worrying and play with white balance

Setting  the correct white balance in a photograph is one of the more subtle aspects of photography, especially in nature and landscape photographs where the “wrong" white balance may produce a perfectly realistic looking image and its adjustment is often a creative choice. Before delving into such intricacies, let’s consider what white balance means  and why we may need to adjust it.

Among its other innovations that are difficult to incorporate into a camera, the human visual system tends to perceive an object as the same color under many different types of incident light, an psychological effect  called Chromatic Adaptation.  This is at first surprising because we see everyday objects by simply seeing the light they reflect into our eyes, so you might think that an  object seen under different light would look quite different.

However consider a green apple; what does it mean to say it is green? Due to their exact shapes, the molecules in its skin can be excited strongly by green light much as a child on a swing can be pushed sky high when pushed at the right frequency. The other frequencies of the incident  light pass through these molecules, and are eventually absorbed into heating the apple. If the incident light is white (ie, approximately equal amounts of every color), most of the green light is reflected while most of the other frequencies are absorbed. But if the incident light is not  white, (such as the blueish light of a fluorescent bulb or the reddish light of a sunset), it is not necessarily true that there will be more green light reflected than other colors because there is simply so much less green light to begin with. However we will typically still perceive the object to still be green due to Chromatic Adaptation in the brain.

As a sidenote, objects also emit some light, but at room temperature, that emission is a very low energy light called Infrared, which our eyes can’t see. However very hot objects do emit higher energy light we can see: think of a flame or its embers, and of course the Sun.

Our chromatic adaptation typically kicks in when we are surrounded by the light source, so everything is tinted, say by a red sunset, and our brain simply corrects for the tint so it can still recognize familiar objects. However when inspecting a photograph in an office, we are never  in the same lighting conditions as the original scene. It this case, the tilt of the light illuminating the photographed scene often appears unnatural, even though it is a completely faithful representation of the original scene.

If  all of the photographed scene is lighted by the same, common type of  light, such as tungsten or fluorescent bulbs, or the direct or indirect mid-day sun, camera or post-processing settings can correct for the overall tint and to make the scene appear as if lighted by white light.  Even if the light source doesn’t fit one of these presets,  post-processing software can typically back out the correct white balance correction if you identify a neutral color in the image, say a white shirt or a gray stone. A neutral gray card can be helpful too;  take one photograph with the gray card in the frame, and another after removing it, and set the white balance on the gray card.

The above hints at why white balance might be problematic in  landscape photography. Sometimes the correct scene looks wrong, the wrong one looks right, and there is a creative spectrum in the middle!  Indeed consider these images of the San Francisco skyline through the  fog. The first in the sequence has no white balance adjustment, and in the following ones I set the white balance on the buildings, the sailboat, and the water. The  first is my favorite as I find it the most visually compelling and its  mood best matches what I remember of the scene. But others will  disagree, and the dirty truth is that there is no right white balance correction of an image.  If anything, I think there’s a case to be made that the most faithful  correction is none at all. Even if you desire the final image to look  perfectly realistic, there will be many white balances which subtly  change the mood of the scene, and this particular adjustment becomes  just another part of the creative process.

Below is the google street view image of this scene.

HDR: Physics and Aesthetics

“I  don’t use HDR, I photograph what I see,” a photographer explained to me in a high end gallery. So goes the refrain of photographers who don’t understand the purpose, or the power of High Dynamic Range (HDR) techniques. They are wrong. By not using HDR, they photograph what the camera sees, not what their eyes see. Divorced from our creative vision, what the camera sees is meaningless and often far different from what we perceive. Photography is an artistic enterprise. We endow a scene with meaning and try to capture it with a camera. But there are always many technically correct photos of any given scene (not to mention those artsy in their technical incorrectness).

Above is a photograph of a yellow sun on a bright blue sky, at least that’s what I saw with my eyes. Many images of this scene were possible, but I  chose to saturate the sun at the bright end and the sky on the black end  to show that the scene has far more dynamic range (range of  brightness) than the camera sensor can capture. You might argue that  this is a technically incorrect image because all pixels are saturated,  on the other hand an image which captures the blue sky saturates the sun even worse! Even so, that image is closer to what our eyes perceive.

Still it is hard to imagine that pure mimicry of human perception constitutes  anything resembling art. We perceive but a narrow band of the  electromagnetic spectrum, from 400nm (blue) to 700nm (red) for the very good reason that this is exactly the peak range of frequencies that our sun emits. On the other hand the exact way we perceive brightness and color, on the other hand, is the result of the evolutionary vagaries of our visual system; there is no artistic choice being made when we look at a sunset. We perceive the particular set of colors that we do  because we have different types of retinal cells (cones) sensitive to  different sub-ranges of this band of wavelengths, and we see brightness  with a different types of cell (rods) sensitive to total intensity with  much higher dynamic range our cameras.

Our eyes effectively burn and dodge overly dark and bright areas; the darker regions of the image formed on the retina rely more on rod response as these cells are more sensitive, and the pupil will automatically dilate to mitigate any excessively bright regions.  Further, psychological image perception mechanisms further help us make  sense of what our eyes see by filling the scene between our narrow  regions of focus.

Indeed  an art or science beholden to exactly what we can see seems  unnecessarily limiting. Astronomers know this well. The universe is  filled with processes generating radiation from radio waves at long  wavelength (meters) end of the electromagnetic spectrum, to x-rays and  gamma rays at the short wavelength end (angstroms and smaller). All must  be synthesized to develop a complete picture of the cosmos. Sure, an  image of the world at radio frequencies would look bizarre in comparison  to how we perceive it with our eyes, but is it less real? Infrared photography comes to mind as a less extreme example.

Returning to HDR, I do empathize with the critiques, but I think  the only justifiable one is that that HDR has simply become a throwaway  image enhancement devoid of any artistic meaning. It’s not a less real expression of the scene, simply one that often substitutes for anything  deeper.

Boston blizzard

Because  I’m cursed with the photographer’s eye, instead of enjoying Boston’s  mini-blizzard last night through double paned glass sipping a cup of Taza hot chocolate, I trudged along the esplanade on the Charles River,  looking for interesting scenes to photograph. After experimenting with  close ups of snow-covered trees and falling snow, I noticed snow falling in front of some distant trees. The effect was fascinating, as if I  were looking at an impressionist painting. (See "Late Afternoon, New  York, Winter" by Frederick Childe Hassam). Using a slow shutter speed only adds to the sense that this is closer to a painting than to a point and shoot photograph. I captures a few exposures, each having a different pattern of snow over the treese.

Some winter photography tips:

Tripod.  I prefer not to push the ISO up past 600 as it creates sensor noise,  and I won't open up the aperture wider than the desired depth of field  of the scene allows. That leaves a long exposure as the last resort to  increase light on the sensor, and a tripod is the only way to do this  without adding camera shake.

Cable shutter release. Indispensable for any long exposure photography, as pressing the shutter button on the camera can create camera shake.

Gloves. Use glove liners inside thick mittens with chemical hand warmers in between.

Microfiber cloth. Wipe snow off your lens or filter with a microfiber cloth.

Manual focus.  As in any low light situation, autofocus is unreliable. Instead switch  to manual and zoom in on the live view image to check focus.

White balance.  It is unlikely that everything in a low light scene is lit with the  same color temperature, so leave white balance as a creative choice for  postprocessing.

Below is the google street view image of this scene.

Moon at Dusk

Is photography documentary or is it playful and artistic? Like most  media, I think it's what we make of it. Last week I used my new prime  lens to play with the moon. The first photograph is very much my style:  nature scenes with shapes, patterns, and an abstract twist. But I  couldn't resist making the second when it presented itself to me  completely by chance near Harvard on the bank of the Charles. Perhaps  I've finally broken into Modern Photography and should move on to a  different hobby before I start photographing run down buildings as social criticism.

Canopy, Timberlands State Park

Shooting straight upward towards the canopy is something I always try in  forests, indeed it's a classic view of the aspens (See photographer Jim Goldstein's version).  Yet I'm often disappointed by the results. The canopy is a busy  mishmash of trees and branches, near and far, high and low, organized  and disordered, captivating and distracting, and its difficult to find a  nice photograph. Hiking with friends in the Timberlands State Park in  Central Connecticut, I saw a very interesting scene looking up. The  colors were vivid and a bit dim due to the strong cloud-cover, and the  scene was almost completely tessellated with distinct leaves. This is the photo essentially as I took it with only minor adjustments to blacks  and vibrance.

Sunset, Carmel Beach

Telephoto lenses are not just for sports and wildlife photographers. In fact, I will go as far as to claim that that the uglier or blander the  scene, the longer the focal length should be. Of course in the rare circumstance where the entire scene takes my breath away, only a wide angle lens can capture the scene as seen by our eyes. But  this is the exception, not the rule. More often than not, the majority  of the scene is disordered and uninteresting, and all the work of photographing it is in finding and isolating a  small, coherent story within it. This was the case on the beach in  Carmel last year. The occasional few foot wave created some interest,  but on the whole the scene felt like the background layers of an  unfinished painting. I sat down on a rock, looked into the surf,  somewhat depressed at the dearth of photographic opportunities. Moments  later I realized that a telephoto lens could save the day. I set up my  tripod and adjusted the focal length so the next wave would fill the  central third of the frame, bounded by the soft, white surf and the  pale, yellow sky. It's no exaggeration to say many of my favorite photographs were taken moments after I had worried that I would end up with nothing worth keeping.

Below is the google street view image of this scene.