Tadpole and small fishes with 680nm

[ins13]

I went to a river to shoot ultraviolet under water, but the first attempt of UV underwater photography was unsuccessful, so I took some infrared underwater photos

 

Olympus em5FS, IR filter 680nm, underwater bag Dicaрас WPS10

combined 3 photos vertically - consecutive from one point - in each pic

 

 

 

and unsuccessful UV photos. the UV section is not the place for it because of very poor quality. I hope the next photos will be better.

zwb2+qb21

above pics - the biotope of riverbank, bottom pics - under the water. these are tadpoles and stems

[nfoto]

The underwater plant in the first picture is Potamogeton perfoliatus Perfoliate Pondweed. A very nice presentation.

[Cadmium]

Wow! Those are both extremely cool shots!

[Andy Perrin]

Amazing!

 

I wonder what a lily pad would look like.

[ins13]

Thank you very very much!!! :)

 

Birna,

thank you for the name of the plant, too ! I tried to find it in a book, but I couldn't )

Steve,

I took a lot of pictures, but more or less "lookable" pics are only these)

Andy Perrin,

I wonder that, too ;) But there were no lilies there. I really want to take pictures of them and will look for them specifically

[dabateman]

These are very good. I like 50:50 shots. The IR really adds to the image.

Since water blocks the UV, I am surprised you saw as much as you did.

[ins13]

dabateman, thanks a lot!!)

Ultraviolet rays penetrate deeper into the water than IR. But in rivers turbidity and a large quantity of organic substances obstruct the passing of UV light due to absorption and dispersion. So there's little ultraviolet under water, but it goes through water.

so there is the chance to shoot underwater UV, but to need to look for clear water with a low content of substances. Perhaps to the autumn rivers will become more transparent to UV

 

wavelength (нм) and depth (м)

 

[Cadmium]

I like the graph. :-)

[nfoto]

Water colour is an indicator of the chance to get underwater UV images. Blue or bluegreen waters tend to transmit UV deeper and in particular, if the pH is low, UV will go further into the water mass.

 

I remember from my scientific research on underwater light climate, many moons back in time now, that we measured IR to be the most penetrating wave region for excessively humic water stained so it almost became red.

[GaryR]

Awesome perspective !

[ins13]

Color of water as an indicator? oh, how interesting!!

In small rivers the color of water is mainly yellowish. But near the surface - for several few decimeters - I hope there will be some small quantity of UV.

 

Steve, I found it on the Internet)) and I don't even know whose it is, it wasn't written

 

GaryR,

thanks a lot!!)

[JMC]

Eka, those two IR images in the first post are amazing. I'd never be able to tell there are 3 images combined for each one.

[ins13]

JMC,

Thanks so much!!))

 

This picture is a panorama stitched from 2 frames. Not seen that stitched because the boundary air-water belongs to one of the shots wholly. The second shot the need for sharpness of the background. If the water surface takes up a lot of space, then to need 3 pictures to ensure sharpness everywhere. I take pictures with the aperture open to make the shutter speed shorter, as objects are moving, waves, swaying vegetation, therefore a single shot cannot make the entire depth of the image sharp.

 

here the shooting line was almost parallel to the surface of the water and nearby the water.

For those two pics in the first post, the shooting line was higher above the water and gradually tilted down and the lens finally went under water

 

 

[Cadmium]

"The minimum absorption, and therefore the greatest penetration is around 420nm, which is on the boundary between blue and violet light."

(NOTE: actually, Wiki shows violet as being 380–450 nm)

https://physics.stackexchange.com/questions/315842/what-penetrates-deeper-in-water-blue-or-voilet

 

They make special 'actinic' bulbs that peak around 420nm, for water penetration in aquariums, especially for coral growth, sometimes to treat jaundice, etc..

[rfcurry]

As Birna mentioned, water color caused by suspended matter, has a lot to do with the scattering or absorption of UV wavelengths in water. Viable amounts of UV may be found at depths of up to 600 meters in the deep sea. (“UV light in the deep-sea: In situ measurements of downwelling irradiance in relation to the visual threshold sensitivity of UV-sensitive crustaceans.” Published in: Marine and Freshwater Behaviour and Proc. R. Soc. B 2007 274, 877-882 Physiology, Volume 27, Issue 2 & 3 January 1996, pages 189–197

 

Here are two images by Prof. Tom Cronin of UMBC at 30' depth:

http://uvroptics.com/images/ProfTomCroninUMBC.jpg