Mushroom Macros - Part II: Camera Settings & Digital Darkroom
In the last post, I covered some of my hardware tips for close-up mushroom photography, including using a geared head and rail for optimum camera positioning and operation. This time we're going to go into how to maximise depth of field through the image; the amount of an image either side of the focal plane that is acceptably in focus. When photographing portraits or animals, it's often desirable to use a shallow depth of field to really bring the viewer's eye to the subject rather than distracting details in the background. Because the depth of field becomes narrower the closer you are to your subject, In close-up photography this can often mean that only a very small part of your image is acceptibly in focus.
Camera Settings
In the early days of digital photography, focus bracketing was something you did manually, either by incrementally shifting the focal point of the camera or by moving the camera itself incrementally closer to the subject. Both processes are extremely labourious requiring far more patience than I could bring to the field. As long as I've been involved in digital photography, however, cameras have included settings for automatic focus bracketing and some even have settings for in-camera focus stacking in which a compiled image is actually outputted by the camera. Bracketing is the process of taking multiple images, stacking is the process of assembling those multiple images to a single output.
So which parameters do I need to pay attention to in camera to get the bracketed images I need for a good stack? It depends. There are so many variables that you need to pay attention to; focal length, distance to subject, aperture (and sensor size) and bracketing settings. Unfortunately there's no one single formula for getting the best results and a lot of trial and error is involved. Michael Guthmann has a good overview of the settings for Olympus cameras including information on the mysterious focus differential setting. My best advice would be to do some test images in a controlled environment at home before setting out. Most shots that I take fall into one of three scenarios; wide-angle macros using the Lumix 9 mm f/1.7, mid-focal length shots using the Olympus 30 mm f/3.5 or ultra-close-ups using the Olympus 60 mm f/2.8.
Most of my mushroom close-ups (I avoid using the term macro, because strictly-speaking a photograph is only a macro when the size of the image on the sensor is the same size or bigger than the size of the subject) are taken with the Olympus 30 mm. You can pick up a used copy of this lens for less than €150 from good retailers, so this isn't going to break the bank. The shot above with the curled leaf is definitely one of my favourites from this season and definitely would not have been possible without stacking.
Here are my standard settings for the three lenses mentioned above. I normally shoot in Focus Stacking mode, not because I use the in-camera stacked image as it is a cropped jpg, but because the jpgs smooth my workflow by functioning as placeholders for my bracketed images. The stacking function is only available for supported lenses and does not work for the 9 mm Lumix, but this lens is so wide that you'll only normally require 3 or 4 images at f/8 anyway.
Scenario | Wide-angle environmental shot | Standard mushroom portait | Close-up or detail shot |
Lens | Lumix 9 mm f/1.7 | Olympus 30 mm f/3.5 | Olympus 60 mm f/2.8 |
Distance to subject (from front of lens*) | 3-5 cm | 10-15 cm | 5-10 cm |
Bracketing mode | Focus Bracketing | Focus Stacking | Focus Stacking |
Number of shots | approx. 20 | 15 | 15 |
Focus differential | 4 | 4 | 8 |
Aperture | f/8 | f/8 | f/11 or f/16 |
Helicon-stack |  |  |  |
In-camera stack | ∅ |  |  |
*the normal convention for measuring distance to subject is distance to sensor, for ease of use I have defined it as distance to the front element of the lens.
I am not a pixel peeper; I concede that the above apertures might not represent the absolute sharpest points of the respective lenses, but this is more than enough to print at maximum resolution for a m43 image - i.e. approximately 51 x 34 cm (or 20" x 13"). These are the settings that work best for me. Your milage will almost certainly differ.
Digital Darkroom
There are essentially three ways to assemble the images; (i) in-camera stacking (assuming your camera does this), (ii) using your go-to post-processing software (ON1 Photo Raw, Photoshop, etc.) or (iii) using third party focus stacking software (e.g. Helicon Focus). All have their pros and cons and I'll go through them below:
(i) In-camera stacking: if your camera offers this, definitely the easiest option but OM System in-camera has two distinct disadvantages; the image is significantly cropped compared to the original images and the output file is a high-quality jpg file rather than a RAW file, limiting editing potential (see the images above) .
(ii) Standard photo editor: using your standard editor allows you to use the RAW images and will involves less crop. The disadvantage, however is that I rarely get a clean focus stack from my editing software (ON1 Photo Raw 2026). Previously, the stack has resulted in unsightly blobs as the software misreads what is actually in focus in the various images, more recently it has resulted in images with thin black lines. Another disadvantage is that ON1 can only process 14 images at a time and so if you have a bigger stack you will have to use multiple iterations.
(iii) Third party stacking: I use Helicon Focus to stack my focus bracketed images. It's very rarely let me down and produces clean images. The only disadvantages is that it comes at an additional price (at the time of writing you can purchase a lifetime lite liscence for $115) and at least the lite version can only output Tiff files (the pro allows you to export DNGs), though this has never affected my ability to edit the images.
Editing
How you edit your images is a purely personal choice. I try to feel my way back to my mood in the forest when I took them. Dark, dingy, quiet. I tend to use a relatively strong vignette, open up the shadows just enough to reveal the details. Highlights can be lightened and shadows cooled down, I tend to boost detail and mid-tones on the mushrooms themselves. The light tones are all natural rather than artificial.
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Close
I'll close with some final focus-stacked images. I still don't understand why hunting for and photographing mushrooms is so appealing, but I know that many fellow photographers feel drawn to them in the autumn in a way that far exceeds any flowers or similar. I suspect that the thrill of the chase plays a role, finding them is often a challenge, and espcially finding a group that's amenable to photographing. No doubt they are photogenic in their own right, but the environment plays a role too.
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