Yep, back to talking about smoke again. I enjoy taking photos of it in different spectra. It’s a fun summer hobby, and it provides a distraction from the fact that I’m definitely breathing in poison and probably going to choke to death.
I’m not going to talk much more about the smoke, as I already talked about it here, and here, and here. To sum it up, the shorter the wavelength of light, the lower the visibility through smoke. In fact, in some situations, near-infrared photographs might be the only way to take a good photo.
In my attempts to appear relevant to today world, I’ve made a few GIF files before. For a change, I decided to create a post focused solely around a GIF animation. Honestly, if I made it right, it should be fairly accessible without any more introduction from me. If anyone actually likes my incoherent ramblings, I wrote more after the GIF, but really, there aren’t any more photos. I’d just skip the rest.
Really, you’re back? Why?
Okay, now I gotta write something. I was just going to pretend, and now you ruined it. I really don’t want to talk about smoke again… maybe talk about the GIF?
One of the longstanding internet debates in on the pronunciation of ‘GIF’. Some people say it should be a hard G, as in ‘Gift’, while others say it should be pronounced with a soft G, as in ‘Jiffy’. Of course, right-thinking people will know that the correct is ‘jigif’, as it is fun to say and is a compromise for both sides(compromise meaning it annoys them both equally).
As most people know, GIF files are used to show low quality animations. I had to make some compromises to create this: Only 256 colours can be used in the picture, so I made each photo(other than the visible spectrum photo) monochromatic in order to reduce the number of colours needed. It’s probably best to compare monochrome photos to other monochrome photos anyways. As well, I made the animation larger, as it seemed to better reflect the colour gradient.
I had looked into other formats that might have allowed for more detail, and was considering making this a APNG file(pronounced ‘jif’), but for all their faults, GIFs are universally accessible across different browsers, and are reasonably compact. They’re still large, so I won’t make them too often.
I also should mention that I decided to cut out any extraneous information, as I wanted the GIF to be fairly accessible. For those interested, the visible spectrum photo was taken with an unmodified Canon T3 Rebel camera, and the others were taken with my modified T3i camera.Both used the Canon 50mm lens, to keep the photos as similar as possible.
The wavelengths given at the bottom are the peak transmission wavelength, or the wavelength where the most light hits the camera sensor. The UV wavelengths are estimates, as my home-made spectrometer isn’t the most accurate. The first UV filter combination seems to have a peak wavelength slightly shorter than the second one, but both are below where I can see light with the naked eye. For the infrared photos, I used the peak transmission wavelength listed for each filter, as they seem to match my approximate results from my spectroscope.
The bars above, showing the spectrum, are also approximate- the Infrared filters, in theory, are ‘open-ended’, and will allow long wavelength light to enter the camera: in other words, the 680 nm filter also allows 760 nm light in as well, and even 950 nm. However, the farther from the visible range, the less sensitive the camera sensor is. All other settings being equal, 760 nm takes a longer exposure than 680 nm, and 950 nm takes even longer. I estimated where the light detected by the camera is less than 50% as bright as the peak wavelength, and used that as the cutoff.
The filters used, in order, were:
Visible Spectrum- no filter, of course… should that be a hashtag?
UV(365 nm)- my triple stacked Schott UG11 and BG40 filters(both pronounced ‘jif’), with my homemade short pass filter
UV(375 nm)- double stacked UG11 and BG40 filters( both pronounced gif in this situation)
Blue, Green, and Red- the visible spectrum photo broken into individual colour channels. There might be a bit violet light in the red channel, but I think the effect is minimal. I adjusted the contrast to each channel individually, and the blue channel was much darker than the red one.
IR(680 nm)- Zomei 680 nm filter
IR(760 nm)- Zomei 760 nm filter
IR(950 nm)- Zomei 950 nm filter
I mentioned that I adjusted the contrast for the individual colour channels, and that the blue channel was originally much darker than the red. That brings up another point I should mention- the shorter wavelengths needed a dramatically longer exposure to obtain enough light. They usually do anyways, as the camera and lens combination I use aren’t the most sensitive to UV light, but it was more than usual. The smoke was also darkening the sky in the UV and blue light range, so the visibility isn’t just the haze, it also results in less light reaching ground level in those ranges. I wasn’t going to deal with that in this GIF, so each photo has the contrast adjusted to make them appear more equivalent.
I’ll probably post the individual JPEGs(pronounced gif) as a bonus sometime(after I eventually complete the last bonus post I promised to deliver a couple weeks ago… it got more interesting that I’d expected, so I’m taking more time to double-check my results). When I get around to this, I’ll also post the photos that didn’t fit with the GIF: my full spectrum photo, the UG11 dual band photo, and a colour version of the 680 nm photo.
Now that I’m done writing about smoke and haze for a while, I’ll just wait around and pretend that I’m not worried about more fires this summer. If they do, expect some more photos of PG(pronounced ‘jif’).