• Ultraviolet Photography

Crowded Bug-Vision flies

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#1 UlfW

    Ulf W

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Posted 15 March 2020 - 14:14

Sometimes a flower can be crowded by several visitors when in the viewfinder.
Attached Image: _MG_5579 120px.jpg

This day I had some luck.
Briefly there was no wind and the fly in focus kept still for the duration of the exposure (1.6s).
The small flower, Ø ca 7mm, had two other visitors at the same time, a bit out of focus.
The flower is a Potentilla erecta.

It was an interesting coincidence that the filter stack was the typical Bug-Vision stack, S8612 2mm + UG5 1.5mm.
Lens: EL-Nikkor 85/5.6 oldest metal type, marked Nippon Kogaku.
Camera: Full spectrum modified Canon EOS 60D at ISO160.
I have not been able to identify the species of the flies.

Edited by UlfW, 15 March 2020 - 17:37.

Ulf Wilhelmson
Curious and trying to see the invisible.

#2 UlfW

    Ulf W

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Posted 15 March 2020 - 17:18

Soon after, the tiny green flies were scared away by the approach of a much bigger fly, in comparison.
When it landed, its weight swung the small flower around.

The new fly was a Hover Fly and I think it is a Marmalade Fly, Episyrphus balteatusll.
Observe the motion blur of the proboscis.

All the settings and filters were the same as above.

This time I took the liberty of posting a full resolution image allowing a zoom in for a closer look at the details.
Click on the image to reach the full-resolution-image.
It is 3169x2547px after cropping so you'll have to scroll in the new browser window.

Attached Image: _MG_5549-full res.jpg

The EL-Nikkor 85/5.6 is a really sharp and nice lens.

One interesting thing to note is that the green coloured stripes of the Hover Fly differ from VIS where they are yellow.

The tiny fly is green both in VIS and with Bug-Vision filters

I think that green colour of the tiny fly is some kind of structural colour, similar to the blue colour of some butterflies.

I needed a lot of patience too, especially as the wind ruined many long exposures.
That day I made over 550 exposures, but the image with the flies was the third from the end before I gave up for the day.

With the selected images I had some luck with the placement of the focal plane too.
For portraits normally you aim for the closest eye. :rolleyes:

I am amazed by how flies, especially Hover Flies, can make sense of the signals from all compound eyes.
I guess there must be some local pre-processing in the eye itself of each compound eye pixel.
Ulf Wilhelmson
Curious and trying to see the invisible.