One type of photography I really enjoy is photographing small things, AKA macro-photography. I love taking photos of insects, flowers, mushrooms, water droplets, watches, jewelry, etc. One of the biggest challenges of macro-photography is the extremely shallow depth-of-field (DOF).
Now the M4/3 system gives us a two-stop advantage in DOF over a FF camera. So my E-M1 with the superb M.Zuiko 60mm f/2.8 macro lens gives me the same working distance and the same DOF as a FF camera with a 120mm f/5.6 lens. At f/8, I get the same DOF as f/16 on a FF camera. But that is still razor-thin DOF: at 1:1 (2:1 in FF terms!) reproduction ratio and f/8 the DOF is about 2mm. So if you’re shooting a 1cm long insect, only about 1/5th of it will be in focus.
The solution to this problem that macro-photography experts have been using for some time is to take multiple shots, sometimes hundreds, at different focus distances. You then stack them together in Photoshop or with specialised software like Helicon Focus. This is a very powerful technique but it can be very time consuming. Also setting different focus distances by hand is a very slow and inaccurate process. This can be quite a challenge if there is wind or your subject is alive and moving.
This is where Olympus’ Focus Bracketing feature comes in so handy and it was one of the reasons I chose an Olympus camera. You just set a focus distance spacing (1 to 10) and the number of shots you need and the camera automatically adjust the focus distance in step and takes the shots in a rapid burst. This makes the process much simpler, more accurate and very fast. You will need to experiment a bit to find the right step size and number of shots for a particular subject. Obviously the combination of aperture setting and focus step must produce files with overlapping in-focus areas and the number of shots must be sufficient to cover the whole length of the subject. I intend to do a bit of empirical experimenting and try to come-up with some guidelines for this.
For now I’ll refer you to a pretty decent article that was published by Olympus themselves: Utilising Focus Stacking and Focus Bracketing in Insect Photography
The PEN E-P5 and PEN F as well as the OM-D E-M1, E-M5 ii and E-M10 ii all have the Focus Bracketing functionality. However only the E-M1 has the capability to also stack the files in-camera and produce a final JPEG. This functionality is not exclusive to macro-photography, it can also be used for product photography, architectural photography and even landscape photography or any time you need to maximize the DOF beyond your lens’ capabilities.