This is my second blog post regarding the expanded depth of field/focus photographic technique. If you are unfamiliar with this technique, please check out my post from July 16, 2012 entitled Expanded depth of field / focus stacking: Introduction. This current installment is an brief overview of the subject, essentially providing a “Table of Contents” for the remainder of this series.
Experience is the best teacher. Don’t expect to achieve your signature magazine cover shot on the first day. (Although it could happen)
Attitude: If I’m irritable or angry, I usually made mistakes that worsen my mood. Some days it’s better to just do the laundry.
Mountain climber’s state of mind: I try to maintain an attitude that I call the mountain climber’s state of mind. A mountain or rock climber might make one or two thousand decisions regarding placement of the hands and feet and shifts of weight during a climb. It takes only one mistake out of the thousands to produce a slip, a slide or even a fall that can ruin that entire climbing experience. Similarly, it takes only one mistake out of hundreds of decisions to render a set of images unusable for a successful composite. Remembering the mountain climber causes me to work very deliberately, move a little slower than usual and maintain awareness of the moment. This produces far fewer mistakes and many more inspiring results than I used to get. Luckily, however, few people have sustained serious injury as a result of a mistake while shooting images for expanded depth of field processing.
Being thorough: The goal is not to create some tack sharp images. The goal is to get at least one entire, coordinated series of tack sharp images with minimal change of position on the sensor. If a few are blurry and unusable, it could render the whole set useless. By remaining aware, mistakes or even possible mistakes can be recognized when they occur. Then the potentially bad image can be deleted and re-shot.
- Camera with manual focus and manual exposure. If your camera has a movable mirror, it’s essential that you have & use the mirror lock-up option. Apart from these details, your camera does not need to be particularly sophisticated.
- Sturdy tripod with feet on a solid surface
- Focusing rail: This is essential for close up & macro.
- Cable shutter release (or remote): This is essential
- Loupe for screen is useful for outdoor work, but not essential. Hoodman brand has a good one, but expensive.
- Cover/cap for viewfinder unless your viewfinder is actually a tiny video display.
- Battery(s) fully charged
- Memory card(s) with plenty of capacity for data
2. Frame your subject in the viewfinder or screen knowing that it will become larger on your sensor at the deeper focal planes than at the initial, close focal planes. This is called “blooming”.
3. Initial focus is crucial. I use a card held immediately in front of the closest point of focus. I use auto focus limited to only the center focusing point and immediately switch the lens back to manual focus. My eyes are not good enough to achieve good focus directly through the viewfinder or on the screen, even when the camera presents a magnified image. For this technique to succeed, your camera/lens combination must be exact and precise consistently. However, people with eyes better than mine can get good results obtaining initial focus entirely via manual focus.
4. Exposure: use manual exposure. Use the aperture that gives the best combination of sharp and depth of field, f/8 for most lenses.
5. Check viewfinder or screen again for subject placement & focus
6. Begin shooting, but remain alert. Whenever I get into a mechanical mode of thinking ( move the rail & shoot ,then move the rail & shoot, then move the rail & shoot), I usually miss something important and end up with a useless batch of images
7. Move focusing rail in equal and very small increments if you want detail in things as small as spines, hairs or pollen. It’s necessary for the areas in focus to overlap between images to get good results. The depth of focus of any one frame depends on your specific lens and its distance from the subject. However it’s not unusual to have just a couple of millimeters, perhaps 1/16 of an inch in crisp focus in any one frame. I usually use increments of 1-4 mm (1/32 – 1/8 inch). The closer the subject is to your lens, the smaller the increment needs to be. Begin at closest point of your subject and move the focal plane gradually toward the deepest part of it. Another advantage is that the smaller increments of change of focal plane between images, the better the chance that you can have a couple of flawed images that you can throw out and still have a successful composite in the end.
8. Lock the focusing rail at each new location to prevent rail sag during extension.
- RAW processing
- Converting to tiff
- Software: I love Helicon Focus 5.2. Its available at HeliconSoft.com. However I understand there are other good programs available.
- Review, retouch
10. ENJOY. You’ve accomplished something that was impossible up until about 10 years ago.
I hope that this will be a help to someone. I welcome comments and criticism.
Through my website at NaturePhotoRehab.com I assist people to transform their photos into impressive works of art that they are proud to give as gifts or to hamg them on their own wall. I provide photo retouching, complex processing and enhancements, prints, enlargements and framing.
©J. Michael Harroun 2012