My Power Pole - Full Spectrum - AM

[xpatUSA]

This shot was taken with the hot mirror removed. Early morning sky colors are less than spectacular around here and there's trees in the way anyhow.

The theory was to try and bring out the reds in the sky (success!) and this shot is more of a test snap than a compositional masterpiece. Posted elsewhere, a shot similar to this brought zero comment and no "likes" and I'm wondering why that was?



Sigma SD14, hot mirror removed, Sigma 18-200mm EX DC OS hand-held, developed in FastStone Viewer.

While viewing, please feel free to play "spot the UFOs"

[TonyW]

As a photograph, I like the stark geometric quality about it.

It's also interesting to see how colours outside the visible range are translated into visible colours by the camera, processing, eye combination. I must admit that I don't understand properly what is happening there.

[xpatUSA]

As a photograph, I like the stark geometric quality about it.

It's also interesting to see how colours outside the visible range are translated into visible colours by the camera, processing, eye combination. I must admit that I don't understand properly what is happening there.

Thanks, Tony.

The shot was made with a Sigma SD14. Most Sigma DSLRs have a "dustcover" in the lens mount. Because the sensor itself has no RGB filter array on it (Bayer CFA) the sensor itself responds to wavelengths from about 300nm to 1100nm. Therefore, the dustcover also serves as an optical filter which blocks both UV and IR. The dustcover is easily removed which provides a camera which responds to the aforementioned wavelengths including near IR. Thus, many colors in a scene will now appear "wrong" in a developed image - for example, green grass shows as brown or sunlit leaves appear as almost red.

The translation into visible colors is done by the raw to RGB conversion - the converter itself has no idea what excited the sensor pixels; all it can do is output visible colors - and get them wrong without the dustcover in place.

[Steaphany]

I term photos like this as being broad spectrum, as the capture extends well beyond while still including the 400 to 700 nm visible spectrum.

Green foliage is normally Orange to Brown in broad spectrum photos as the IR becomes mapped into Red and when combined with the Green yields the Orange to Brown hues. Healthy plants only absorb Red and Blue light, They reflect Green which we see and Infrared which only the camera sees.

Nicely done

and I do not see any UFOs

[JBW]

i see one in the top left quadrant.

[xpatUSA]

i see one in the top left quadrant.

Two to go, Brian . . .

[Dave Humphries]

I see one in the top left quadrant.

Two to go, Brian . . .

Hi Ted,

I only saw that one yesterday, but knowing there were two more was a challenge I couldn't resist - and I have found them
(well I think I have)

Both in lower left quadrant; the most prominent is between transformer and tree, plus a really hard to spot one at the tip of a pointy branch on tree; about 420 pixels across from left edge and 77 pixels up from lower edge.

A good trick to help find them is to view in LyteBox, click and hold mouse button, then roll mouse (and image) around in small circles.

I assume the "UFOs" are dust bunnies? - gotta wonder where that name came from.


Ted/Steaphany;

What causes the 'lateral CA-like' edges on pole, etc.?
Dark things are bordered by a Blue edge on their left and Red edge on their right.

Is that a feature of the sensor?
Afterthought: Or perhaps it is my monitors and me looking way too closely

Thanks, Dave

[Steaphany]

I assume the "UFOs" are dust bunnies?

That's how I saw the image anomalies.

Now if someone does get to photograph a craft carrying rich kids who make Bleep Bleep noises in front of blokes no one will ever believe, at least ask to borrow a pen, pencil or ash tray and forget to give it back.

[JBW]

Two to go, Brian . . .

I now have seen two but more importantly i have seen one of the pilots in the tree to the left! (for this you need to enlarge the shot)

[xpatUSA]

Hi Ted,

I only saw that one yesterday, but knowing there were two more was a challenge I couldn't resist - and I have found them
(well I think I have)

Both in lower left quadrant; the most prominent is between transformer and tree, plus a really hard to spot one at the tip of a pointy branch on tree; about 420 pixels across from left edge and 77 pixels up from lower edge.

Hello Dave,

I found one more at about the same location. So now there are five:

I assume the "UFOs" are dust bunnies? - gotta wonder where that name came from.

Not sure what they are because I haven't looked for them yet, sorry.

Ted/Steaphany;

What causes the 'lateral CA-like' edges on pole, etc.?
Dark things are bordered by a Blue edge on their left and Red edge on their right.

Is that a feature of the sensor?

Another shot had more of that effect. It looked to me like halos exacerbated by the funny background color and by some overly-enthusiastic sharpening/detail contrast in post:



As to CA, the 18-200mm lens is not one of Sigma's finest but good enough for IR/FS work.

As to the sensor, it has two versions and the one on the SD14 does not correct for off-axis rays.

Brian, can't see the UFO pilot in the tree yet. Must be my un-calibrated monitor

[JBW]

The classic uside down egg head shape, 2 bright eyes and a round bright mouth... we have the proof!

[IzzieK]

UFO or dust bunnies I like the spectrum of the shot. +1 to Stephaney's comments.