Sitting in the dark wating for my turn on the rope I found myself watching the tiny droplets of water forming on the ends of a small group of straws, eventually each droplet growing larger and larger before finally dropping in the small pool of water beneath, It was not possible to see the tiny crystals forming within the droplets of water with the naked eye I found myself wondering do they all took the same up-close? And what actually takes place withing that tiny droplet of water? With this in mind I decided to put a date in the diary to investigate further with the help of my camera and macro lenses.
After many cups of tea and much debate with my fellow cavers around the pot belly stove at the Wessex I decided that Hunters lodge sink would be a good place to start, logistically straightforward, nice and dry and with plenty of straws within reach of my camera lens.
I opted to keep my camera kit to a minimum, 100mm macro lens and x2 adaptor, camera and a mixture of different small LED torches in place of flash guns although there are some minor issues with the quality of light you get from some LED lights. The constant real time feedback you get from static lighting and the benefits of being able to focus easily on a constantly lit subject outweighed the minor light quality issues. Plenty of hand and lens cleaning cloths and a decent tripod and remote shutter release also on the kit list.
After making my way into the cave with kit in tow I set myself up adjacent to a nice cluster of straws and after carefully selecting my first interesting looking subject I got set up for the first shot. Balancing three lights on nearby rocks I was able to achieve some nice lighting, the translucent straws taking the light really well and the back light in particular bringing out some of the finer internal detail of the formation, being very careful not to blow out any highlights with a miss placed light.
Setting my camera files to RAW enable me to capture as much information as possible, aperture set to f11 - f13 iso as low as the exposure will allow ideally iso 100 to keep the colour noise to a minimum.
Because of the three-dimensional nature of the subject and the fact It is only a very small 3-4mm across and how close you need to get in order to reveal the beautiful details hidden within the water droplet on the tip of the straw, I am only able to achieve a very shallow depth of field in one singe exposure, so my only option was to produce a focus stacked image. With my camera firmly fixed to my tripod and cable release in hand I started by focussing on the very nearest part of the straw and gradually adjusting my focus manually, small increments at a time, rotating the focus ring to the left moving the depth of field through the image from front to back with each exposure now capturing a tiny piece of the puzzle, a small slice of in focus image just a tiny bit different from the last.
I soon realised on carefully reviewing each image at a time that I was looking at between 12 and 20 frames per subject in order to give me the depth of field I needed in the final image. Because of this number of frames necessary to make the final image It's very important to make sure that there is no chance of the lights or the camera moving between frames. Any lighting movement or the slightest nudge of the camera between can make blending the images into one at the post processing stage significantly more challenging! The use of a remote cable release is essential in keeping your hand away from the camera and minimising any chance of moving the camera while tripping the shutter.
I also opted to take a few wider images without the x2 adaptor and by not being so close to the subject I was able to achieve a sharp subject from front to back in 5 – 6 frames, with a handful of different options now in the bag I decided that a cup of tea at the Wessex was now in order and a chance to review the images!
With all the images now imported into lightroom I can start the process of combining the frames and making the finished images. After toggling through the images to check there weren’t any glaring errors to any of the exposures it was time to make the basic processing adjustments.
Starting with the first image 1, I worked my way through the range of basic adjustments, contrast, curves, texture, clarity and sharpening etc, and when I was happy with the overall look of the first image allowing for the fact that much of the image it’s self will be out of focus at this stage! I copy the settings (adjustments) and proceed to paste them to the whole run of exposures that relate to the final image in insure processing consistency in the first instance this was to a batch of 16 frames in total, these frames were now exported into Photoshop for aligning and blending.
Because I have adjusted the focal distance across each of the exposures this has effectively zoomed ever so slightly with each frame, resulting in each consecutive image being slightly bigger than the last. Because of this each image will need to be adjusted for scale and alignment with the other images. Now It is just the case of selecting all of the image layers and hitting edit – auto align, auto align should now make any necessary adjustment to each of the layers to make them ready to blend. Now selecting edit – auto blend Photoshop will blend all images together producing you one single image with a much greater depth of field and revealing all of the beautiful detail not visible by the naked eye!
Something that became quickly apparent across the run of frames is that the water droplets form at very different rates dependent on the water flow to each individual straw and the ever growing droplet across each frame was too much of a challenge for photoshop to align the images with any accuracy. The relatively static droplets in other images were not an issue, something I will have to bare in mind in the future.
All that’s left to do is make a few last tweaks to the combined image and I’m finished.
On reviewing the finished images you can really see just how individual each formation is in the way it is formed, despite growing from the same rock at the same depth just feet away from each other. Each one like a snow flake beautifully different, completely unique from its neighbour just inches away.
In conclusion Focus stacking in macro photography is a captivating and rewarding technique that allows photographers to reveal the hidden intricacies of tiny worlds. Despite its complexities, mastering focus stacking opens up a realm of creative possibilities, enabling us to capture and showcase the finest details of subterranean subjects with exceptional depth of field. With careful planning, technical expertise, and a discerning eye, photographers can unlock the full potential of focus stacking, offering viewers a unique perspective into the awe-inspiring world that lies beyond our naked eyes.
