distance with ultraviolet and infrared

[charlie chipman]

I don't really know where to put this so I will put it here, it is something I did for another forum some time ago I thought I would share here as well, may be interesting to some. Feel free to move this thread to a more appropriate section of the forum if you see fit.

Here I will demonstrate the amount of haze there is in the ultraviolet spectrum, and how you can see further with the Infrared spectrum than ever before. This is just a playful demonstration, nothing more

These are all shot with my D70 I have modified for infrared and ultraviolet photography. This means that the internal filter has been removed so when I take a picture with the camera with no filters attached it is contaminated with Infrared creating a colour cast (and soft images due to focus shift between the spectrums).

Anyway here is a picture straight from the camera, aside from the colour cast the scene looks pretty close to as I saw it out of my own eyeballs as far as the clouds and mountains in the background look, typical los angeles scenery this is shot at the ballona creek wetlands near marina del rey.



This next picture I used the Baader U filter (passes approx 300nm-400nm) that blocks all visible light and Infrared light leaving only the ultraviolet spectrum to reach the sensor. As you will see the mountains in the distance just up and disappeared as well as the definition in the clouds. The foliage turns dark because it absorbs UV.



This final image I used a B+W 093 filter (850nm-1100nm if I remember correctly) that blocks all of the ultraviolet and visible spectrum's leaving only Infrared (or near infrared if you want to get technical) with this filter and a custom white balance pictures come out of the camera monotone, was not converted after the fact. As you will see there is not as much haze and the mountains in the distance are more defined as well as the clouds. the foliage turns bright white because it reflects massive amounts of IR.



So anyway, this is just a little comparison of what happens at different frequencies of "light". You can view the red, green, and blue channels of your visible light photos and see much of the same effect only not this extreme.

And finally, I assigned the UV picture to the blue channel, the visible picture to the green channel, and the IR picture to the red channel to come up with a multispectral picture. perhaps if we could see in the UV and IR spectrums as well as the visible spectrums our world would look something more like this.






So if you want to make the distance disappear shoot UV. If you want to see further that our eyes can see shoot IR (I hear this works shooting through heavy rain too), and if you want to be reminded of your hippy days combine everything all the time.

[Asher Kelman]

Hi Charlie,

I like the idea of going multi-spectral. One are you refocusing with a different setup or just using a small aperture?

I'd like to see the UV not contributing a thing to the mountains or sky, as these can be modeled better (ie more more drama) with IR and visible light. I'd have a separate UV masked area to add selectively maybe to put a tad over the furthest mountains.

I'm thinking in B&W. for that reason, going multi-spectral would allow much more choice in assigning different wavelengths ("colors") to tonalities of grey scale.

It seems hard to alter colors in your picture.

This is a good experiment. I hope you'll share more. I'd love to have a camera with a multifilter turret to change filters!


Asher

[charlie chipman]

Ahh a turret style filter would be great.

I used F/16 or f/22 for this and did not refocus, just quick and dirty. You can see in the M.S. version the power poles on the left are doubled (or tripled). Ideally to do this one would want to use the Coastal Optics 60mm UV-VIS-IR 1:4 Apo Macro which has no focus shift between 3 spectrum's but it is somewhere in the neighborhood of $4k-$5k.

One thing about my M.S. picture is since the visible light picture had IR contamination a "true" multi spectral picture (using a green filter for visible light) would have darker red foliage compared to the orange that you see here.

I like your idea about masking the UV for more detail in the distance. Sometimes UV though can give a quite pleasing rendition of distant objects, it has it's own signature so to speak.

Here is a High contrast B&W from joshua tree in UV, if the mountain was much further away it likely would have vanished (like the clouds that were in the scene), but since it was not to far it has a very nice soft glow to it which is not a product of post processing. If you keep this in mind UV shooting can be quite rewarding.

[charlie chipman]

And wait until you see what UV does to peoples skin.......

[Asher Kelman]

Originally Posted by charlie chipman

And wait until you see what UV does to peoples skin.......

Ugh!

Use it on flowers. Then you will find runway lights for insects!

Asher

[Bart_van_der_Wolf]

Originally Posted by charlie chipman

Here I will demonstrate the amount of haze there is in the ultraviolet spectrum, and how you can see further with the Infrared spectrum than ever before. This is just a playful demonstration, nothing more

Hi Charlie,

Thanks for the demonstration, it may be an eyeopener for some. If I may suggest, I'd remove the color in the UV spectral image as it might confuse the average reader not accustomed to looking at spectral bandpass images.

These are all shot with my D70 I have modified for infrared and ultraviolet photography. This means that the internal filter has been removed so when I take a picture with the camera with no filters attached it is contaminated with Infrared creating a colour cast (and soft images due to focus shift between the spectrums).

I'm not sure, but does removing the filter of the D70 also remove the anti-aliasing filter?

Bart