In terms of photographic equipment and technique the big change has been that I have started using a full frame camera with a manual focus macro lens to photograph invertebrates.
From 2007 to mid 2020, when photographing invertebrates I used close-up lenses mounted on fixed lens small sensor bridge cameras or on telezoom lenses on micro four thirds and APS-C cameras. With all of these I used autofocus.
And with all of these setups I used minimum aperture so as to get as much depth of field as possible. This equated to around f/45 for full frame. This is a much smaller aperture than most people would use because of diffraction destroying fine detail at such small apertures. However, I found that with suitable post processing I could get acceptable results as long as I kept the outputs small. I settled on 1300 pixels high for images prepared for viewing on screen.
In the summer of 2020, with Coronavirus limiting me to our garden, with only a limited range of subjects, I decided to have a serious attempt at getting decent images of some very small flies on our tiny pond. I had tried before but had never managed to get satisfactory results. I spent some hours single-mindedly concentrating on them, but to no avail. Eventually I came reluctantly to the conclusion that I simply couldn't get sufficient depth of field for these tiny subjects. That was with single images. Focus stacking was impractical because the flies were hyper-active and typically flew off after one, two or not many more seconds.
The full frame Sony A7ii had been sitting on the shelf unused for months. The only subject matter I thought it suitable for was sunsets, and I hadn't been doing any of those, especially since being confined to our home and garden in the Spring.
The problem with the small flies was insufficient depth of field. I knew that when using the higher magnification that was needed for smaller subjects I could get greater depth of field if I used a macro lens, extension tubes, teleconverters, bellows and/or reversed lenses. This is because the effective aperture gets progressively smaller as the magnification goes up, according to the approximate formula:
Effective f-number = Nominal f-number * ( 1 + magnification )
where "Nominal f-number" is the f-number you set on the camera/lens. So for example if you use f/l6 at a magnification of 3:1 then the Effective f-number you are using (which is what determines the depth of field) is
f/ ( 16 * ( 1 + 3 ) )
which is around f/64.
In contrast, I was limited to f/45 with all my close-up lens setups because the effective aperture does not change with magnification when using close-up lenses.
So, by using effective apertures smaller than f/45 I would be able to get greater depth of field. That would be good for the small flies, although with apertures even smaller than f/45 the loss of detail from diffraction would be even more serious, so much so that the images might be unusable. Based on a very brief experiment some years previously that is what I believed would be the case. However, since I had the necessary kit, and having plenty of time on my hands and not much by way of subjects to photograph, I thought I would see what happened if I tried using even smaller apertures to photograph the tiny flies.
I had various kit I could use, including a Laowa 25mm macro lens that went from 2.5X to 5X magnification. It was a Canon EF mount lens, so I could use it on my Canon 70D dSLR, but I also had adapters so I could use it on the A7ii and on my micro four thirds cameras. I tried all three. Here it is shown on the Canon 70D.
Click on an image to see a larger version
The screen on the A7ii gave me a clearer view of what was going on than the other cameras, and that was important as the Laowa 25 mm macro is manual focus only, so I needed to have as good a view as I could. Also, the A7ii gave me a stronger focus peaking signal than my micro four thirds Panasonic G9, which also made it better for manual focusing (and the 70D didn't have focus peaking). So the A7ii turned out to handle best for me.
To my surprise I was ok with manual focus. The failure rate was high, but I wasn't surprised by that given how small and how active the subjects were, and I don't think autofocus would have been any better. And most important, where the focus did fall in the right place, the image quality looked to be better than I had managed with any of my close-up lens setups. This is one of the early shots that convinced me that this tiny aperture approach might work for small subjects. This one was captured with the A7ii and Laowa 25mm macro.
This led on to a number of experiments with various cameras, lens arrangements and flash setups. As I tried various lenses and combinations of lenses and teleconverters I came to realise that not only did the tiny aperture approach work for small subjects, but it could give me better results with larger subjects too. Here are some examples from the test sessions. These two were captured with a Sigma 105mm macro lens and 2X teleconverter on the A7ii.
I am currently (at least for now) using a pair of 2X teleconverters and a Laowa 100mm 2X macro lens, which like the Laowa 25mm macro is a manual focus lens.
I have been getting results that I like with effective apertures much smaller than the f/45 equivalent of my close-up lens setups. It turns out that some modern processing software can pick up weak signals of detail from images that are highly softened from diffraction, and can bring those details into visibility without looking forced or unnatural. To do this I am shooting raw and using DXO PhotoLab for raw conversion and some associated processing, using Lightroom for image-specific adjustments, mainly to tonality, and cropping, and using Topaz DeNoise AI for output sharpening and noise reduction.
There are some examples in the next post.
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