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Multispectral movies

UV Video
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#1 Jim Lloyd

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Posted 30 July 2018 - 20:13

Art hat on.

Experimenting / playing: Video here


D3200 full spectrum camera
ASA 800
EL-Nikkor 80 mm f/5.6 (metal)
f 5.6
Hoya u-330 1.5 mm filter plus S8612 2mm
Processed in Premiere Pro
(Neat Video Noise reduction plug in)

Rather dull day, so low light levels, giving noisy images. Rather than trying to white balance I have been trying other approaches to giving "pleasing" image (can't think of the right word at the moment). Previously I was doing channel swaps (G-B, seemed good), but here I have rotated the hue by 90 degrees which gets away from the magenta look

Initially I found images to be very noisy - the Neat video plug in works well to reduce this. Other experiments I have done noise has been less of a problem.

#2 Andy Broomé

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Posted 31 July 2018 - 02:38

View PostJim Lloyd, on 30 July 2018 - 20:13, said:

here I have rotated the hue by 90 degrees which gets away from the magenta look
Interesting video, Jim, especially with the undulating leaves turning from orange to red (or perhaps yellow to orange-red). I'm supposing the red/orange-red areas are the shadows.

What does "rotate hue by 90 degrees" mean?

#3 Andy Perrin

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Posted 31 July 2018 - 02:43

Andy B.- I think he means like on the hue saturation brightness color wheel. The hue is given by degrees on there.



Jim, a fun thing to do is first WB, then convert to Lab color space, and invert one or both of the a and b channels.

Edited by Andy Perrin, 31 July 2018 - 03:08.


#4 Jim Lloyd

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Posted 31 July 2018 - 06:12

Andy B - yes as Andy P says. There’s an effect in premiere pro that allows you to changes hues by altering angle around colour wheel. If you turn on Lumetri scopes you can get a nice graphical representation of this so you can see what effect it’s having.

Thanks for suggestion Andy P. However one of the reasons for looking for alternatives to WB is that I haven’t found a way of WB for a movie yet. This particular filter stack (“bee vision” ?) is particularly tricky I find. But I will look at your idea.

#5 Andy Perrin

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Posted 31 July 2018 - 06:23

Jim, one of these days I will learn Python so that other people can use my scripts. I could easily write some code to white balance for you, but it would be in MATLAB. It is frustrating.

Edited by Andy Perrin, 31 July 2018 - 06:24.


#6 Jim Lloyd

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Posted 31 July 2018 - 14:04

One of these days I will learn MATLAB !

#7 Andrea B.

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Posted 01 August 2018 - 13:51

Jim, if you need to white balance a video, start with a converted Sony, Olympus or Panasonic Lumix all of which seem to be capable of setting white balance through a UV filter. Not quite always accurately, but still better than nothing.
Andrea G. Blum
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#8 Jim Lloyd

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Posted 05 August 2018 - 21:55

Thanks for the tip Andrea. I can't decide if I should be white balancing anyway.

Here is my next experiment.

Information is given in the caption on vimeo.

At first I was using premiere pro to put this together, but its rather slow and cumbersome. I found that I could make all the adjustments I wanted in the VLC media player on the fly. This included quite good flicker reduction (although a lot remains).

Not sure what to make of this ...I think it might have something to say to me, I'll need to watch a few more times to know what.

This is not like a science experiment where you have some idea where you might be heading (a hypothesis or an idea of what you are trying to achieve)

Images are noisy as underexposed even at f/2.8 iso 1600, particularly as its quite dark in parts of the wood.

I am influenced by thinking about how the bird sees the wood. But it becomes clear that, one can't escape it being about how we see the wood and how the camera sees the wood. I think its very difficult to make it really from a bird's viewpoint, but I think if we can at least use some thoughts of how the bird perceives to de-familiarize our own view - then that's some success.

Edited by Jim Lloyd, 05 August 2018 - 22:09.


#9 Andrea B.

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Posted 06 August 2018 - 13:26

That de-familiarization sounds like a good approach. And makes for interesting tri-part views of the woods. Human, bird, camera.

I wonder if you are approaching this too broadly? For example, what happens if you explore how a bird sees a leaf or how it sees nesting materials. Do you have a UV-photo of a bird's nest? Perhaps if you examine the separate parts of the forest, that will lend some insights into looking at the whole via human/bird/camera vision? Just a thought. But I don't want to interfere with your explorations!!!

The Wikipedia entry on bird vision mentions that blackbird bills are UV reflective and this is used for mating signals. I'm going to stake out our local black birds and try to capture this! (I don't recall what kind of blackbird was written about.)
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#10 Jim Lloyd

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Posted 06 August 2018 - 14:43

Those are all very helpful thoughts Andrea - thank you - watch this space ...

#11 Jim Lloyd

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Posted 12 August 2018 - 18:11

Explorations continue ...

maybe a little bit of gratuitous knob twiddling here, but I am thinking about how the technology influences how we see the world... Maybe that whatever art we make can't escape from being partly about the technology and materials we use:

"What we observe is not nature itself, but nature exposed to our method of questioning. "

Werner Heisenberg

#12 Andrea B.

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Posted 12 August 2018 - 19:32

....hence the uncertainty..... :D

I once read that bird photographers disdained bird photos containing man-made objects. (Always shoot "bird in tree". Never photograph "bird on fence".) But I have always liked just the opposite. I want to see how the birds interact with the man-made world. How does the bird change the hard metal, shiny glass, cement paved human world? How does the bird see our world in its birdy vision? I think sometimes that birds adapt to us better than we adapt to them.

OK, I liked that movie better. More dynamic. There were breezes stirring the leaves. I liked the slow "window" thing moving across the scene. (I do not know what that technique is called.) Do you think it might be nice to actually have a bird in one of the movies? Or is it better just to hear them?
Andrea G. Blum
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#13 Jim Lloyd

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Posted 12 August 2018 - 20:01

Thanks Andrea - Yes definitely think I need to film / photograph some birds...

#14 Jim Lloyd

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Posted 12 August 2018 - 21:22

Any suggestions for suitable bird shooting uv capable lenses ?

#15 Andy Perrin

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Posted 12 August 2018 - 22:10

Don't shoot birds with UV. That's mean! :(

(I think nfoto once reviewed some 500mm lenses on here? Let me check.)

ETA: It was a 400mm.
http://www.ultraviol...8031#entry18031

For more convenient birdwatching, I have a Meyer-Optik Gorlitz Telemegor 180mm that is decent and not too hard to carry around.
http://www.ultraviol...lemegor-180mm55

Edited by Andy Perrin, 12 August 2018 - 22:22.


#16 Andrea B.

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Posted 12 August 2018 - 23:16

.

I hope we all understand that if photographer refers to "shoot the bird", he or she means "photograph the bird". :lol:




I was a bit hasty in suggesting bird photos in UV !! That is a tall order. What I meant to say when I wrote that was that I hoped to see a bird flutter through the woodland scene more or less by happenstance. Trying to sneak up on a bird and deliberately photograph just that bird in ordinary visible light requires the patience of the saints, a lens longer than most of us own, fast auto-focus, tracking and more. And a camouflaged bird blind is often quite useful to the effort.
Andrea G. Blum
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#17 Andy Perrin

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Posted 12 August 2018 - 23:30

Goodness, you make it sound impossible, Andrea! I was thinking of something more along the lines of setting up a big lens and waiting for a bird to come into the frame. Then you snap the photo. (I should add that all my own bird photos have been this kind of thing, and usually by accident too.)

Edited by Andy Perrin, 12 August 2018 - 23:41.


#18 Andrea B.

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Posted 13 August 2018 - 02:59

I saw an unusual bird in my backyard about 18 years ago and had no way to get a photo of it to prove that I had seen it. I vowed to get a digital camera to have ready for the next sighting of any unusual bird. That was my Nikon Coolpix 990 which of course was completely useless for bird photography. But that little camera was the first step in a very cool digital journey which eventually led to UV photography and this website and to making UV friends around the world. B)
Sometimes you start off on a trip to the grocery store and wind up on Mars.
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#19 Andy Broomé

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Posted 13 August 2018 - 03:28

View PostJim Lloyd, on 05 August 2018 - 21:55, said:

I am influenced by thinking about how the bird sees the wood. But it becomes clear that, one can't escape it being about how we see the wood and how the camera sees the wood. I think its very difficult to make it really from a bird's viewpoint, but I think if we can at least use some thoughts of how the bird perceives to de-familiarize our own view - then that's some success.
One thing to bear in mind is that regardless of how a bird interprets the EM spectrum, given the position of their eyes on the side of the head, their vision would not be rectilinear (owls and some other birds of prey may be the exception).

So, you would probably have to shoot with 2 cameras facing away from each other, each with a fisheye lens (which makes attaching a UV filter difficult) and somehow combine both left and right footage into one 360° equivalent view.

#20 Jim Lloyd

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Posted 13 August 2018 - 15:19

View PostAndy Broomé, on 13 August 2018 - 03:28, said:

One thing to bear in mind is that regardless of how a bird interprets the EM spectrum, given the position of their eyes on the side of the head, their vision would not be rectilinear (owls and some other birds of prey may be the exception).

So, you would probably have to shoot with 2 cameras facing away from each other, each with a fisheye lens (which makes attaching a UV filter difficult) and somehow combine both left and right footage into one 360° equivalent view.

Yes it is in my mind a lot that by concentrating on the spectral aspects there is a lot else that I am ignoring, but I figure that this is a very long project and I can only do so much at once. So the aspect you refer to has been nagging me in the back of my mind for a while, without having had chance to think it through properly. The book here is influenced by this thinking, although maybe not in an obvious way, more the thought that the bird might have one eye focusing closely for food and the other distant for predators - although that isn't supposed to be taken too literally.

One thought related to what you say above is simply to project the two images side by side

A more generally thought is that there is a difference being being inspired by bird vision and trying to reproduce it. Photography and film is very rectilinear and I think maybe we forget sometimes how very different this is to how we actually perceive the world. This doesn't stop us using it as a medium to explore the world around us artistically. I guess that is probably because we have learnt the language which has evolved over time. I am struggling a bit to exactly articulate what I am saying or what the end product might be, but I guess it is to do with using insights from bird vision to extend an artistic language rather than trying to build some kind of simulator that puts us inside a bird's head...

Just got another 6 years before I have to get this idea nailed !