Started 3 months ago | Discussions thread
OP gardenersassistant Veteran Member • Posts: 8,962
Re: Horse-fly

Paul Pasco wrote:

Impressive detail


and one wouldn't expect two 2X converters to be this sharp. How did you happen to try this?

I value depth of field over fine detail and for over a decade I used minimum aperture with various setups, 1/2.3", micro four thirds and APS-C. That was all with close-up lenses on telezoom lenses. I used f/8 on 1/2.3" bridge cameras, f/22 with a 45-175 on micro four thirds and f/22 to f/32 with a 55-250 on APS-C. Unlike macro lenses, extension tubes, bellows and reversed lenses, with close-up lenses the effective aperture does not increase with magnification, so all of these setups gave me around the depth of field I would have got using f/45 on full frame.

For some years I tried, with no success, to photograph some very small flies that turn up every summer on the tiny pond in our garden. Last summer I tried again, and tried really, really hard, but I still failed. With these tiny subjects I simply could not get enough depth of field from single shots, and they were hyperactive and so focus stacking was out of the question. I came to the conclusion that I was never going to be able to get decent shots of those flies, at least not with the kit I was using.

I decided to try another approach, using smaller effective apertures to get additional depth of field. Several years previously I had tried using even smaller apertures and it didn't work out well and I concluded that it wasn't practical. There is obviously significant loss of detail from diffraction softening with the apertures I was using, but I could get images that looked good enough for my purposes with some careful post processing. But with the even smaller apertures the diffraction softening became unmanageable.

So, with this background, I had no reason to think that using even smaller apertures would work, but I decided to try anyway; I couldn't think of anything else to try.

I started with powerful macro lenses, the Canon MPE-65 1X to 5X and the Laowa 2.5X to 5X. Using these I could get smaller apertures than before because of the effect of magnification on effective aperture. I had tried the MPE-65 before but didn't get on with it and got rid of it, so I bought one again, and also the Laowa.

To my surprise, it turned out that I could get images of those little flies that were good enough for my purposes. It was difficult - the kit was heavy and cumbersome, and unlike with my close-up lens setups I couldn't use autofocus. Still, it was possible and I did get a few images of those tiny flies before they disappeared. That was enough to send me into an almost manic experimental phase lasting up until the end of the year.

I also still had a 1.4X and a 2X teleconverter from those earlier experiments and so I tried using them with the macro lenses, and that let me use even smaller apertures. I tried lots of combinations of those two macro lenses and then other macro lenses with and without various combinations of teleconverters (and also mixing in extension tubes and close-up lenses), including the purchase of a second 2X teleconverter so I could try using two of them together. I tried all this on micro four thirds and APS-C, and then bought a full frame camera to try it all on, and also bought a Laowa 2X macro lens to try that.

The more I practiced, the better my focusing success rate improved, until eventually I got a higher success rate than with my autofocus close-up lens setups. And there turned out to be advantages not just with very small subjects, but with larger subjects too such as medium sized flies and wasps, spiders, snails, woodlice etc.

By the end of the year I had come to the conclusion that the Laowa 2X on full frame with a pair of 2X teleconverters worked best for my purposes. That setup let me get to f/90, but I found that f/45 was the smallest aperture with which I could produced results that I thought were acceptable. Using f/45 gives me effective f-numbers from around f/56 at 1:1 to around f/132 at 8:1. At 8:1 the scene size is 4.5mm x 3mm, and even with a lot of practice that is about as small as I can handle hand-held in the field (I don't do any studio photography.)

I was pretty burnt out by the end of the year and took some time off from photography. For the last several months I have continued experimenting with hardware, flash arrangements and processing. That is ongoing.

As to two 2X teleconverters being sharp - they aren't, at least not the way I'm using them. Because of the large amount of diffraction softening with the apertures I'm using the images often appear to be completely unusable. It needs some quite strong post processing to get them into (what I consider to be) a usable state, and that is only possible (for me at least) if I keep the images small. I process them for viewing on screen at 1300 pixels high, with the images produced at that 1300 pixels high so there is no provision for zooming in to see more detail (which wouldn't be there if you could look closer).

As an example, in the illustration below the images on the right are the preview JPEGs in raw files, resized to 1300 pixels high. On the left is the central area of the 1300 pixel high processed images shown at 100% in Faststone image viewer.

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