Color & Light
Meeting Photo Challenges
Creative Image Processing
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Creating Better Photographics
Night & Low Light Photography
Light & Exposure
Close-Up & Macro
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Choosing & Using Lenses
Digital Photography Equipment
Macro Photography: Using Depth Of Field & Flash
Macro photography is all about details. That’s why we photograph small subjects. But I have seen hundreds of macro pictures and the lack of sufficient depth of field is the biggest problem. If much of the picture is blurred, that defeats the purpose of the photograph. For example, why would you want to render any part of this orchid (#1) out of focus, even slightly? Backgrounds can be completely blurred to direct all of the attention to the subject. The foliage behind this poison dart frog (#2) is just a haze of color with no definition at all. That’s fine, but notice that the frog and the flower are both tack sharp.
Macro is not as easy as photographing people, architecture or landscapes. Macro is much more technical. You can’t just pick up your camera, take some close-ups and expect them to be excellent. I am specifically referring to the need for depth of field and critical focus, and that means you have to use a tripod.
As you make the lens aperture smaller for increased depth of field, you lose light. That means the shutter speed has to be longer to compensate for the loss. Longer shutter speeds mean you will not be able to hand hold the camera to get sharp pictures. Small apertures like the ones you use for extreme close-ups, like f/22 or f/32, will force your shutter speed to be much slower than you could hold steady—unless you raise the ISO to a higher number, which I don’t recommend for macro work. As long as your subject isn’t moving, it doesn’t matter how long the shutter is as long as you are using a tripod.
Keep It Parallel
The seashells (#3) and the macaw feathers (#4) are both flat subjects and it was very easy to angle the camera so the planes of the subjects were parallel with the back of the camera. Had I not been this careful in my work and the camera was oblique to the subjects, even with f/32 the depth of field might not have been as complete as it is in these 2 photos.
Often it’s impossible to make this happen. Most of the time your macro subjects are not 2-dimensional or on the ground and you may not be able to angle the camera in the way I’m suggesting. Whenever it’s possible to use this parallel advantage your depth of field will be guaranteed.
One way to block the wind is to set up a white tent that completely covers the subject. You can use white parachute material that hangs over 4 stakes in the ground, and that not only prevents a delicate subject from moving in the wind, it also diffuses the light beautifully. Even on a bright day with an overhead sun, you can take stunning macro shots in diffused light. I photographed a captive luna moth (#5) using this tent. In my opinion, this kind of ultra soft lighting is the best-case scenario in macro photography.
When using a ring flash, I suggest shooting very close to the subject. That’s why it’s best to use a 50mm or 100mm macro lens. The working distance with these lenses is close—within 5-20”. If you use the 180mm or 200mm macro lens, the working distance is much further. The problem with doing that is the light from the ring flash almost becomes a point source of light (like from a regular flash) and that means the light itself becomes harsh. The closer the light source is to the subject, the more diffuse its effect will be. You don’t want a harsh light source on your macro subjects.
Focus Bracket Your Way To Deep Depth Of Field
There are 2 software programs that enable you to have complete depth of field at any lens aperture and with any amount of magnification. One of them is called Helicon Focus from Helicon Soft (www.heliconsoft.com) and the other is Zerene Stacker from Zerene Systems (www.zerenesystems.com). Zerene Stacker is better for extreme magnification. You can think of them as the HDR for focus and depth of field.
The way they work is that you take many pictures of a subject—anything not moving—from a tripod. Each time you take a picture, re-focus the lens from the furthest point in the composition to the closest point near the camera in very small increments. It doesn’t matter how many shots you take. My average number of exposures is 10 to 12. The software then assembles all of the pictures and uses only the sharpest plane of focus from each photo so the resulting composite is perfectly focused throughout. Since f/8 is typically the sharpest lens aperture on any lens, you can do this at f/8 and still have complete depth of field from the immediate foreground to the background.
This can be used for macro photography as well as when using a telephoto. What is amazing is that if you use a long lens, you still get the telephoto compression but everything is tack sharp from front to back. Here is a link for a demo of Helicon Focus: www.heliconsoft.com/heliconfocus.html and a link for a free trial of Zerene Stacker: www.zerenesystems.com/cms/stacker/softwaredownloads.
You have a choice with respect to how much of the subject you want to be sharp. In the shot of a rhinoceros beetle (#9) I wanted the entire insect to be sharp but I felt it was important to leave the background completely blurred. For the first exposure I focused on a point on the insect furthest from the camera. For the last exposure, I focused on the bark at the bottom edge of the frame. In this way, I chose the specific areas of the picture that I wanted to be sharp. I used f/8, and took 10 separate pictures that were stacked together in the Helicon Focus software to produce exactly what I wanted.
I used Helicon Focus with the photo a wasp nest with eggs in the various chambers (#10) and again I selected a specific area of the image that should be sharp. I focused the first picture at the outer edge of the nest, and then 12 shots later I ended with focusing on the nearest point on the nest. The background tree remained a blur of color. I felt that if it were sharp, it would be distracting.