Welcome to the Essential Light Photography Blog By Jim Sabiston

Tuesday, September 28, 2010

The Time Traveler

One of the aspects of photography that few consider is the dimension of time. I'm not speaking to the fairly straightforward matter of shutter speed vs aperture here. As specialized technologies can extend human sight to the extremes of the electromagnetic spectrum – think x-ray and infrared imaging as common examples - photography has the ability to extend our vision to include the dimension of time.

Most photographic images are, in one form or another, created by recording a specific and finite moment, typically measured within some very small fraction of a second. This is desirable, as this gives a very clear, detailed image for whatever purpose the photographer has in mind, be it posterity or art. We are 'freezing a moment in time', as it is frequently described. Most photographers never depart from this standard approach. Time, as an element in the image, is usually no more involved than a quick calculation in concert with the aperture opening to compose the subject in a particular way.

There is a whole other world out there, however, existing in the intersection of light and motion. It is possible to step back a bit and actually reconsider time as an integral part of the moving world. It is also possible, with a bit of thought and creativity, to include time as an integral part of the photograph. The results can be quite stunning and bring an entirely new perspective to the viewer.

Most of the time, movement is the enemy of the photographer. Movement blurs details and can ruin an otherwise good photograph. Thus we have faster lenses, more sensitive sensors and film combined with the requisite blazing fast shutter speeds. My Canon 5D MkII is capable of shutter speeds as fast as 1/8000 of a second. It is difficult to even comprehend how short a span of time that is. In some circumstances, such as sports and action shots, or trying to freeze the motion of a hummingbird wing, these capabilities are not only desirable, but necessary. To introduce the element of time into an image, we need to go in the other direction, however. A sports photographer may want a bit of blurring in order to convey movement and action, so will use a slightly slower shutter speed to do so. A nature photographer commonly uses a slightly slower shutter speed to the same end. This is most commonly seen in water shots, where the movement of a stream or waterfall is intentionally allowed to blur slightly. This has the effect of both softening the look of the water and brings an element of life to the scene by highlighting the movement of the water in the stream or waterfall. The results can be quite beautiful. Still, in these shots we are typically using small fractions of a second. Most of my images of this sort use a shutter speed in the area of ¼ second or much less. Time is used sparingly and discreetly.

(click image to enlarge)
It is possible to use much larger chunks of time. When this is done, the resulting images change utterly and with them our view of our world. We suddenly begin to see things as part of a continuum rather than a single, unique instant. One of my more popular photographs is of an abandoned and deteriorating dock on the Wicomico River in Maryland. It took over a year and several attempts to get this shot. The dock had fascinated me and I longed to capture the subtle character of it that intrigued me. Dozens of shots were taken and discarded. They just lacked that certain something I saw there, but couldn't quite translate to the image. Finally, one morning I was out before dawn (again!) to try and shoot a bald eagle known to spend the night in a local tree and I found what I was looking for. The morning was windy with intermittent rain, what most people would describe as 'miserable', and accurately so I suppose! The eagle shot did not work out, but walking back along the river I passed the old dock again and was struck by the conditions. For how many years had this old dock weathered such storms, and yet here it still remained? It was showing the years and mileage for sure, but still standing.

I quickly rearranged my entire concept of of what I had been trying to do with this subject. I set the camera up on its tripod, being extra careful to ensure it was planted solidly on the grassy shoreline of the river. I then installed a polarizer and four stops worth of neutral density filters, cutting down the light coming into the camera lens by a total of six stops. It was still overcast and dark. If the sun had risen it was impossible to tell, but I needed the low light in combination with the neutral density filters for my intended shot. Once set up, I attached the remote shutter release – it was imperative that the camera remain absolutely motionless. The shutter speed was set to 25 seconds.

I clicked the shutter and waited what seemed an hour while the seconds ticked away. I then took some bracketing shots at slightly different settings as insurance, but the 25 second exposure was the best in these conditions. I stayed out and took a few more shots, but none really panned out after the dock shoot, as the rain became heavy and the lens was getting too wet. I packed up and walked back to the bed & breakfast where a hot cup of coffee and my ever patient wife were waiting. I eagerly loaded the files into the computer and, finally, there it was, the image I had wanted all along.

(click on image to enlarge)
The long exposure blurs the choppy, windblown waves into a smooth gradient. The rain disappears into a smooth gray mist. The far shoreline a hint of another place. But the dock stands fixed and sharp, as the elements pass around and over it, the dock seemingly permanent and immutable by comparison. But we know the opposite to be true. The dock is already clearly past its prime and the slow, steady wear of the elements will continue to take its toll. If we could extend the exposure long enough, over many decades, we would see that it is the old dock that is the ephemeral element here. The river and wind will remain as elements long after the dock has gradually faded away.

Everything is in motion relative to everything around it. If there exists any constant in the universe, this seems to be it. With a little thought, creativity and patience, the camera can allow a small glimpse into this rarely seen or considered world.

Sunday, September 19, 2010

Hey! Meter THIS, buddy!

Last post we took a look at exposure compensation on the family point-n-shoot camera. Today we will look at a different way to control the camera's automatic exposure mechanism that doesn't require fussing with all the controls.

Whenever you point your automatic camera at a subject, the camera's light meter adjusts the aperture and shutter speed to what it 'thinks' is the best combination of settings to give the best photograph. Modern cameras have gotten very good at this. As long as there is sufficient light and the level does not exceed the dynamic range of the sensor, it is quite easy to end up with very respectable images from a technical point of view - sharp focus with a decently balanced exposure. As we covered last time, adjusting the exposure compensation moves the 'center point' that the camera uses for averaging the exposure either up or down as desired. This works quite well, but once set you have to live with those settings unless you go back to the menu and change the setting yourself. No big deal really, but it is just one more thing to forget when you are supposed to be having fun.

There is another easier, faster way to achieve the same result, and it does not require accessing any menus that you have to remember to go back and reset. All you have to do is point the camera at a spot that is lighter or darker than your subject, push the shutter button half way down to set the exposure and focus, swing the camera back to the actual subject you are interested in and push the shutter all the way down to complete the shot. It's that easy and fast.

One of the great advantages of the modern family camera is that the image on the sensor is shown on the rear lcd screen. It is this feature that makes our little trick workable. Lets try a little exercise:

Take your camera somewhere where there is a significant variation in light range. This can be inside near a lamp or outside in an area with mixed sun and shade. Turn on the camera and slowly sweep it across the scene such that you cross both dark and light areas during the sweep. Watch the lcd to see what happens to the different light and dark areas as you sweep across the scene. What you are seeing is the camera constantly adjusting to the light conditions as you move it. These changes are reflected right on the lcd! You can actually see the averaging being done in real-time.

Now, do the same sweep again, but this time at some point pick a fixed target, say the brightest spot in view, and push the shutter button down half way. You will see (and probably hear) the camera set the exposure and focus for that particular scene. This happens very quickly, usually in about one second. Once locked, continue the sweep while continueing to hold the shutter button in place at the half depressed point. Notice that the camera is no longer adjusting for the changing light conditions! Once the shutter button is partially depressed, the camera locks its settings until either the button is released or you push it down all the way and activate the shutter, taking a photograph. You can use this characteristic to your advantage.

The idea here is to simply use the natural automatic meter function of the camera to do the hard work for you, but to still have the camera take a picture that is quite different from what the automatic settings would give. I have included two images below for examples. Both images are of the same stairway outside the Morgan Library in Manhattan. I selected this spot as it had some interesting detail and textures and, most of all, some great reflected dawn sunlight shining right on it. The photographs are taken within seconds of each other, so the conditions are identical in both frames. Notice the dramatic change in the images, however!

The first shot is taken 'straight'. I placed the camera between two upright columns, framed the details I wanted and then activated the shutter. The camera did all the work. The reflected lighting is fairly soft, so the entire scene is within range and we end up with a good detailed image. While the camera did a great job of recording the actual scene, the image is otherwise rather uninspiring  and the brightest areas are actually a bit 'hot'.

(click on image to enlarge)

Next, I took the camera and pointed it at the bright blue sky and pressed the shutter down halfway. Once the camera audibly registered the exposure, I turned back to the stairs and tried to repeat the composition from the first shot - all the while holding the shutter button in the halfway position. Remember, this prevents the camera from readjusting the exposure to the darker stair scene. Once in position, I activated the shutter. Notice the dramatic difference between the two images.

(click on image to enlarge)

This image is probably a little too dark, depending on exactly what I was going for, but notice how much more dramatic the light is!  This shot illustrates one of the two main drawbacks of this method of adjusting the camera metering: the inherent lack of precision. The good news is, assuming you have the time to try different settings, is that you can see the effect right on the lcd and quickly meter to a different lighter or darker target as needed. With practice, you can get fast, consistent results. The second drawback is the potential impact on sharp focus. The camera sets the focus on your target at the same time it sets the exposure. If the difference is extreme enough, your shot can be noticeably out of focus. The trick is to try to find a metering target that is roughly the same distance as your final target. This is potentially more of an issue with closeup shots. The small lenses in these cameras are actually pretty forgiving on this point, but it pays to be aware of the issue so you are less likely to be surprised by it.

So there you go! Quick and easy 'manual' exposure control of your automatic camera.

Monday, September 6, 2010

If I had a camera like that...

A slight change in direction for this week. I was going to post about more extensive processing techniques, but it occurred to me that there was a topic that might have more immediate benefits for some of you. I will take up the processing discussion on a later date. Instead, I will discuss how to use the more common point-n-shoot camera to obtain better photographs.

A frequent comment I hear at the shows is “if I had your camera, I could take those good photographs, too.'

Well, maybe yes, and then again maybe no. The fact that they are making that statement tells me that they don't really understand photography, so its probably 'no'. Does pro grade equipment take better images? Of course it does, why else would we spend $1,500 on a prime lens or far more on a pro grade dslr body if it didn't improve the quality of the photographs we take? But, in truth, it is only part of the answer. That good glass and pro dslr combine to give some amazing potential for the photographer. But there is the key word: potential. Higher resolution, better quality pixels in larger sensors and world class glass are going to contribute something to the final product, but it is the photographer that determines the results. The main advantage of the higher grade equipment is this: control. The photographer simply has much more control over what the camera is doing. The typical consumer camera is largely an automatic device, removing all the decision making from the photographic process. For the average user, this is actually a good thing, allowing them to take far better photos than would otherwise be likely. The problem for the more capable photographer is that the averaging software that makes these cameras work tend to produce 'average' photographs. Good photography requires that the photographer put something of themselves into the image. In short, this means the photographer must control what the camera is doing. This, in turn, means the photographer has to understand how the camera works. This means much more than pointing the camera at your subject and pushing the big button. A real measure of a good photographer is one who can take great photographs with less than ideal equipment.

I will touch on some of the options available and cover a few of the simple tricks to help you along with those all-to-common automatic point-n-shoots to get better images. The first thing to do is familiarize yourself with the equipment you happen to have. We will assume for this exercise that the camera is a typical, completely automatic consumer camera. I will be using a Canon sd550, a pretty typical example of the type: decent build quality and feature set, 3X zoom, auto everything with some optional style and environment adjustments. This camera is a few years old now and has provided good service as the basic go to camera for family photo album type shots.

The good news is that new cameras are offering more and more manual control options. Even this 'older' camera has some things we can adjust. A quick look at the rear of the camera and I see a dial that lets me switch to one of several modes, fully auto, Manual , Scenes and video. The Manual setting is the one we are most interested in. This opens up several control options which are very useful, if a bit limited. The first and most important is Exposure Compensation, right at the top of the menu on the little Canon. Exposure compensation is a tremendously useful feature that allows you to adjust the scale on which the camera averages the image exposure. The adjusting range is usually plus or minus two stops of exposure (this is a significant amount). Adjusting increments are in 1/3 stop increments, giving thirteen setpoints.

In a full sun shot with some shadows, the camera will average the exposure such that it gets what it considers the best overall balance. The result is that the brightest spots will be 'blown out', that is, that part of the image will be pure white. This is because the amount of light will actually exceed the range of the sensor's ability to record it. At the other end of the range, the deep shadows will probably lack detail and may even be completely black.

I took the sd550 out in the yard and took three shots of one of our young cats. The shots were taken in the exact same conditions: Full, bright mid-afternoon sun. I took a shot at the two extreme ends of the adjustment range and the center (normal) setting. We will start with the first shot, with the exposure compensation set to -2 stops:

(click on image to enlarge)            Photo #1: Exposure Compensation= -2

Note the overall shot seems a bit dark. The mid range of the photo has been dropped down significantly, but most of the image retains good detail. Look at the shadows and you will see that the shadows are completely black, showing no detail at all. On the other hand, the whites of the fur retain full detail and color. This is the tradeoff at the low setting. Now, watch what happens when we restore the exposure compensation to '0' , the normal default setting (bearing in mind the furball model refused to sit still for the shoot!):

(click on image to enlarge)             Photo #2: Exposure Compensation= 0

This is the normal image you would get under the full automatic setting. Note the light and dark extremes have been averaged. The result is that the shadows now show good detail. The small bit of white fur is actually blown out to pure white, but the area is so small that I does not detract from the image. If the white patch was larger, the camera might have sacrificed some of the shadow detail to pull down the whites a bit.

(click on image to enlarge)             Photo #2: Exposure Compensation= +2

Last is the +2 setting. The change here is very dramatic, with almost the entire frame overexposed. Even the wood surfaces facing the sun have blown out to full white, retaining no detail at all. But look into the shadow areas, especially beyond the bench, which were pure black in the first image and only retained moderate detail in the second image.

This exercise illustrates one of the fundamental controls available to the photographer. I typically use exposure compensation in brightly lit situations to lower the exposure by about 2/3 to a full stop. I shoot in full manual, so I make this adjustment on the fly. An automatic camera will make the adjustment for you if you use the option. The main advantage of this ability, as I most frequently use it, is that I can offset the exposure of highly reflective surfaces to retain detail in those areas of an image. I can refine the exposure in the body of the image later on the computer if desired. With high-end post processing software, I can adjust the light and dark areas individually to retain full detail across the entire image, compensating for the limitations of the camera sensor. Ideally, the user of a point-n-shoot camera can use this to further refine the images a bit better than the camera will, left to its automatic settings.

For the next entry, we will study a technique for 'fooling' the camera sensor to change the exposure setting to were YOU want it to be. See you then!