Fleeting Glimpse Images : Visions in words ~ Sagas in light: Technique

Inside the Limit

Fri, 20 Jun 2008 03:46:07 GMT

Using Lens Limitations to Your Advantage

Blog readers, I am still traveling out west. I haven't had much time to write or even do much shooting. For those of you waiting for news of my recovery from my last disastrous post, suffice it to say, I am ok and the gear is recovered. On with the show.

The occasion of our visit out west put me at my nephew and God son's baseball game. Ever eager to try out new shooting opportunities, I looked upon cheering my nephew as a shooting opportunity. Baseball is played in the late afternoon and evenings. Light is constantly changing. In this game, we had bright sunlight, a thunderstorm blocking the setting sun, twilight, artificial lights and everything in between.

Shutter speeds on my Canon 70-200 MM F2.8L IS Lens ranged from ISO 200 at 1/2000th of a second to ISO 500 at 1/320th of a second (all at F2.8). The failing light and the razor-thin depth of field kept me on my toes.

The construct of the ballpark also tried my skills. It seems that ball parks are constructed of chain link fence. In my youth, chain link was limited to a tall behind-the-plate backstop and a waist high boundary down each foul line. Now, fences are much higher and surround the entire field. The fence mesh openings are smaller than the primary of most telephoto lenses making for difficult photos-not to mention finicky auto-focus mechanisms.

There are few options for the budding sports photographer. The openings are typically limited to the dugout entrances and the outfield corners. These views are limited in revealing most of the field and are often clogged with inbound and outbound players. The outfield openings are simply too far away to make effective photos.

The view from the scorer's booth is safely above the fence but offers a less exciting view of the action and looks more like the shots taken from the stands than action at the player's eye-level. It is also uncomfortable shooting over the scorer's table and the people who need to be there.

The winning solution to the dilemma is to take the tack of submarine captains everywhere and get inside the range of the torpedo before it can arm itself. With a camera lens this means you must get inside the focus ability of your lens. The telephoto lens I was using focuses to roughly 1.5m on the close side. I was already limiting my aperture to the widest setting (yielding the least depth of field) for the purpose of faster shutter speeds.

By closing the distance from my lens to the fence I was able to shoot through the fence. I placed the center of my lens on the 'hole' in the links and moved it until my lens hood rested on the fence itself. At this close range, the fence becomes all but invisible. Long focal length, combined with wide-open aperture and close proximity to the fence render the steel barrier practically invisible. The shot above of Mat sliding into first base was shot through the fence at relatively close range.

Ball games aren't the only place where getting inside the resolving limit of your lens can be a benefit. Zoos, construction sites, highway bridges and many others are locations where mesh of one kind or another can be negated by judicious placement of your lens in proximity to your barrier. It is also much easier than trying to clone out fuzzy diamond-shaped patterns.

del.icio.us Tags: sports,fence,mesh,telephoto,action,focus

The Low Down

Thu, 01 May 2008 15:07:08 GMT

del.icio.us Tags: nature,wildflowers,flash,macro

One of the big mistakes most people make when taking pictures is they way they stand-or rather that they stand. Kodak taught us long ago to hold the camera to our eye and steady ourselves before snapping the picture. What resulted from this was a generation of photographers who learned to take pictures at 4.5 feet off the ground.

Just thumb through your picture albums and you will see that most pictures of children have the ground or the floor as the background because the parent is shooting down on them. How much more engaging is a picture when we put ourselves in the perspective of the subject?

A child will always look better when photographed at eye level. The same is true of many other objects. I was out shooting wildflowers at Big Woods State Park yesterday and this was on my mind. Actually a lot of things were on my mind. Last week's article was about a different trip to Big Woods where I concentrated on using flash in bright daylight. This trip was the same except that I was concentrating on using flash that wasn't affixed to the camera.

This photograph is only possible when you have the flower at eye level. Unless your flower grows five feet tall or you have a convenient ditch in which to stand, you are going to have difficulty getting this perspective on a subject.

I laid on my stomach for this shot but was propped up on my elbows so the camera saw about 12 inches from the ground. It matched the height of the blossom nicely.

Sometimes it is necessary to get even lower if your subject is particularly low or you are adjusting the placement of the background in your image.

This shot of an emerging bloom was taken from about 6 inches off the ground. In order to move the orange glow closer to the blossom and give the top of the frame a little more interest. From a little higher placement at capture, I would have moved the lower part of the background higher in the picture and lost some of that delicious orange color that makes the image for me.

A little off camera flash to the right lights the flower and leaves the background dark. Leaving me with a flower that pops and a background that compliments but does not compete.

Other times you dig down deep to get some foreground in shot. This can be particularly helpful in creating an artistic context to the shot.

In this shot, the camera is two inches off the ground and I am using the foreground grass as a diffusion element to give an impressionistic feel to the image. This flower was in total shade so I didn't use a flash , being satisfied with the soft light as it was.

The shallow depth of field of the macro lens enhances the dream-like quality of the image and makes it softer and more painterly without having to resort to software.

Bottom line is get to the bottom. Go low to match your subject's perspective and you will be rewarded with pictures that look nothing like a snapshot.

Considering Fill-Flash

Wed, 23 Apr 2008 19:57:17 GMT

Spring is in the air-finally. Those of us in Minnesota saw our last snow melt a week ago. Those of us in Minnesota who are photographers are itching to get shooting. Today, in spite of the poor light (blue skies and mid-day sun), poor conditions (windy) and poor time of year (brown vegetation with sparse emerging plants), I went out to practice some manual flash techniques in preparation for the wildflower season.

Round-Lobed Hepatica

Having spent some time over at the Strobist's Blog, I have been eager to try out some less-than-automated flash photography.

Though armed with reflectors and sunlight my wildflower photos have been lacking something-some extra punch. I decided that maybe a little manual shooting like I did in the old days before Aperture Priority and Flash before ETTL, was in order. This is a departure from my usual technique to use natural light and then do the remaining corrections in image editing software.

This close up shot of a solitary blossom shows potential. It has some nice backlighting by the 11:00 AM sun and though I was able to keep from blowing the highlights and plugging the shadows too much, the flower ended up being much darker than the background. I was using a silver reflector on this shot.

"What a difference a little
well-placed flash can make!"

In the second shot, the same blossom was photographed with the Canon 580EX flash set to 1/16 +.3 EV power at 90° with the bounce card deployed. As you can see, the flower is much more evenly illuminated. The background, while lighter, no longer dominates the flower. The nice backlighting provided by the sun is still present as are the shadows cast by the petals in the upper left. Overall this image is going to be much easier to work with in software.

The real difference in the images to those who like to use software like Photoshop, Photo-Paint, Paint Shop Pro and Elements, to enhance their images, can be seen by reviewing the histograms.

Comparing the histogram without flash on the left with the histogram from the flash photo on the right we can see that the images are going to be different animals when it comes to editing. Most of the pixels in the normal exposure are in the second darkest stop of the image where Fill Light adjustments are normally applied. In the flash exposure, more of the pixels are in the Exposure Range of the histogram. Notice too, that the blacks are much heavier without the flash and actually plug on the blue channel. In the fill flash shot, the blacks are fewer and don't plug. This seems intuitive: more light = less blacks and darks.

Here's the rub: The highlights are actually better in the flash shot! The non-flash shot has plugged shadows in the blue channel and almost touches the wall on the left meaning highlights are approaching white. A little highlight recovery might be in order for the non-flash image.

What does it mean? The flash image has more to work with in areas that are going to lend themselves to editing. The non-flash image needs highlight recovery and black and fill light areas boosted. Those types of adjustments introduce noise and posterization if done too severely. What a difference a little well-placed flash can make!

It all goes back to the adage: Get it right in the field and you will spend less time in the software at the desk. The choice of using a little fill flash on an image that I could likely have easily recovered means I don't have to do that bit of extra work. I can easily apply this technique to situations where I might have trouble doing it in software later.

In this flash shot, the flower above is backlit by the sun, the flower in the middle is in shadow of the blossom above and the blossom below is reflecting direct sunlight at the lens. A flash allows me to expose them all properly and control the brightness of my background at the same time!

So everyone, visit the Strobist Blog and then let's all go out and flash something.

Leaking Megapixels Down the Drain

Sat, 05 Jan 2008 21:31:30 GMT

del.icio.us Tags: Digital Photography,Level,Image Quality

You might be pretty proud of that new camera you just bought and how it has a daunting megapixel count. Bigger enlargements are yours for the simple exchange of a few extra dollars right? Not necessarily.

Many people ignore... Let me back up. Techniques seems to have suffered as a result of the digital camera revolution. With so many things repairable in software, photographers have become haphazard in their photographic technique. Image stabilization, color correction, and full auto settings, focus, etc on the in-camera side and powerful software tools on the editing side have let us slide into blissful laziness when it comes to taking a photograph.

I bet everyone out there has a photo like this one. You are perched on a hillside watching the dramatic sunrise looking at all those stunning colors, you snap the picture, review the LCD display and hoot (See Chimping) like a dominate ape. But when you get back to the home photo lab, aka your personal computer, you find that the image is slanted a few degrees to port or starboard. Continuing the naval metaphor, you decide to get your picture back on an even keel. Software can fix anything. Right?

Every image editor out there has either a dedicated horizon straightening tool or at least the ability to rotate an image, either interactively or by degrees. Here is a quick tutorial I made for Corel PhotoPaint X3 users. So, you straighten that leaning image of Pisa, or that level water that appears to be running downhill to the right or to the left and all is well with the world. Right? Wrong!

Some of your precious pixels leaked out. You didn't even notice-did you? If you read Part 1 of my article on the three Cs of image editing will remember that straightening an image is the same as cropping an image.

As illustrated then, straightening a picture and yet maintaining that 'parallel to the floor' rectangular shape requires that little triangles of image be trimmed off of each side of your image. How much area is lost depends upon how far off from level your image is, and, to a certain extent, depends upon the format of your image. A camera sensor with a 3:2 aspect loses pixels at a different rate than a 4:3 sensor or a medium format with a square sensor. Since most DSLRs are 3:2, I did my calculations on that proportion. Though the rate varies, it is safe to say that you loose 3-4% of your total pixels in an image for every degree you are required to rotate to bring your image to the desired orientation. If you get to 5% rotation, the figure is a daunting 21.7%. (Pixel loss was measured using Corel Paint Shop Pro Photo Horizon straightening command and comparing image size before and after rotation of degrees on a 3:2 image.)

Now, if you paid the extra bucks to buy that Rebel XTi instead of the Rebel XT and you were negligent enough to let your camera get off by five degrees, your adjustment to straighten your image just cost you the difference in megapixels you paid to go up to the next model camera!

Beyond the pixel loss due to these cropped triangles, every pixel in your image suffers. Pixels are square. You can rotate them 90, 180, or 270 degrees without having to re-interpolate the image. If you rotate to a degree measurement other than the cardinal degrees, you are forcing your software to recalculate the values of every pixel in your image. You will lose detail. You will be farther from the reality you captured.

The Letter A in the example above is an illustration of non-cardinal degree rotations. The A on the left is as typed in the image editor: Corel PhotoPaint. The Center A was rotated 27°. The Right A has been rotated back 27°. Notice how much more sharp Left is than Right. This is a result of software interpolation of square pixels on rotation of less than 90°. Even a degree of rotation will introduce softness and loss of detail in your images.

The simple solution is to to take special care to orient your camera to the level items, be they vertical or horizontal, prior to snapping the shutter.

	A simple way to ensure you are level is to actually level your camera. This starts with leveling the tripod. If your tripod has a bubble level, use it to keep your rig level so that even if you rotate the center axis you remain level. The second item is an on camera level. A $30 investment here can ensure that you have adequate level of the camera as you set up.
	If you don't have time to set up, use the edges of the view finder to align you with the horizon or a known vertical or horizontal. You can use focusing points inside the camera to accomplish this as well. This helps people who can't get a tripod set or are following fast action.

The bottom line is keep that bottom line straight. A really fine capture isn't ruined by a slant but the ability to print it at maximum quality and size is diminished.