photograph heat rising

[fletch]

Originally Posted by Palladius

* Commence geek-out: All hot bodies (i.e. all objects above absolute zero) will emit radiation, and the hotter the body is, the shorter the wavelength (starting with high frequency radiowaves for seriously, seriously cold bodies, working up to infrared wavelength for bodies at room temperature). This is probably why we associate infrared radiation with 'heat', since it's the wavelength emitted by objects that count as hot in the narrow range of temperatures we need to survive.

When a body gets much hotter than room temperature, up to thousands of degrees, it starts emitting light in the visible spectrum, starting at red light at about 3000 degrees Kelvin working up to blue light at about 8000 degrees Kelvin (and beyond that, ultraviolet). Astute readers will note that this roughly corresponds to the numbers we use to indicate white balance and colour temperature. It may also explain why physicists might look at you weird if you show them a reddish tinted photo and say it has a warm colour temperature... red light is emitted by much cooler bodies than blue light.

**End geek-out**

Oooh - I love a good geek out.

One slight puzzle from this is why are tungsten light bulbs that emit more red light hot where as flouresent light bulbs are cold but emit more violet light?

[kencaleno]

Originally Posted by fletch

He is not trying to photograph actual heat though but the effect that heat has on light. Therefore standard photography is the way forward.

As Palladius stated the 'heat haze' effect is cause by small pockets of air a different temperatures messing with the light causing object viewed behind the haze to be blured. This photo found on flickr proves it is possible.

http://www.flickr.com/photos/schoolb...ry/1840433194/

I tried a google search on hints for capturing it but there wasn't anything, only advice on how to avoid it so doing the oposite might help. Seemed the key thing was shooting a long way away using a long focal lenght.

Edit: more examples, seems common factor is focal length

http://www.flickr.com/photos/8622063@N04/2386245165/


http://www.flickr.com/photos/raycollister/2560203327/
http://www.flickr.com/photos/14691648@N06/2514988860/
http://www.flickr.com/photos/blissimages/508567801/
http://www.flickr.com/photos/stevebirrell/204277025/
http://www.flickr.com/photos/11371618@N00/2150662307/

I thought you meant heat rising as from a hot clothes pressing iron or a fart even!

[tzava]

i got a 500mm reflex f/8 tokina lens .. will give it a try as soon as the weather permits.
thanks for the answers.

Going to try the boiling water this weekend, almost done my diy studio ( empty 2 room apartment, construction lights 500w each, 2 pieces, found some black-outside-silver-iside umbrellas for 4 $ each ).

[fletch]

You might struggle to create the affect atrificially. It think it become more visible when the effect is a long distance away, therefore the long focal lenght. Not just due to the long focal lenght. You might need to wait for some hot weather but its worth a try.

[jdepould]

I managed to capture the shimmer working on my ice racing stuff last weekend.


FWIW: D300, 200-400mm f/4 @ 400mm; 1/500s, f/11 @ ISO200

I think the low angle helped to get the shimmer. Most of the others from that day don't have the effect, so it's hard to say what really made it show up.