What caused the shadow?

First observation...... If you look at the two pictures taken with the flash they are taken from a different location than the two without the flash.

Second.....If you were to take a flashlight and hold it where the camera and flash was and point it toward the mic stand you would see that the beam of light would have to make a left turn to cause the shadow on the wall where it is located and that just doesn't happen, Jeff

The cord goes into the white trunking just above the skirting board.
The trunking ends somewhere behind the lectern, so we'll not see where it goes without a photo form another angle...

Frog,
Your powers of observation are remarkable.
Yep the wire is in a plastic sleeve and it runs to the podium PA.
Now the purple tint on the window is probably due to the pale lavender glass panes. Guess the bright daylight bleached them out but left a little tint.

Thanks again for all replies, I'm going to be more aware of flash pictures and see if the shadow continues to appear.

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Originally Posted by Frog

I guess they must be flash shadows then, as they disappear with no flash.
I'm not sure how they show up on his right when you are on his right. I'd think the flash would throw shadow to his left.
I still don't know what causes the purple fringing on the window frame and now I want to know why there is a very short electric cord that goes nowhere in the wall.

edit: I see now that the cord goes into a tube or something along the wall.

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The shadows can fall on 'both sides' as the flash 'spreads out' and isn't perfectly straight out of any flash, let alone an on camera one. This is not a 'point source' light as with flash you want it to diverge to cover as much area 'evenly' as possible. Short of perfect alignment, and due to previously mentioned bounce effects, the shadows can fall in odd ways. The photographer is undoubtedly not exactly the same height as all the other objects in the photo, the camera/sensor plane may not be perfectly parallel to the subject and on and on all which can cause minor variants in how the light will cover the face of the objects.

The purple stuff? That is Chromatic Aberration. CA is a lens distortion/aberration problem that appears frequently with certain classes of lenses at wide apertures. This photograph being made a f/2.7 is prime candidate for such an issue. CA is simply (or simplistically if you prefer) the light begins to be prismatically split in the Chromatic region and with the current coating and construction of modern lenses appears as a purplish fringe in areas the are highlighted to the point of being 'blown out'. Most lenses that display the problem will have it disappear by stopping down the aperture.

Quote:

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Originally Posted by Frog

I guess they must be flash shadows then, as they disappear with no flash.
I'm not sure how they show up on his right when you are on his right. I'd think the flash would throw shadow to his left.
I still don't know what causes the purple fringing on the window frame and now I want to know why there is a very short electric cord that goes nowhere in the wall.

edit: I see now that the cord goes into a tube or something along the wall.

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The purple fringing is chromatic abbreviation (spelling or wrong word??) of the lens, and its visible due to the difference in outside and inside lighting (contrast), the light is also saturating the image sensor also and that also compounds the effect.

The purple fringing looks characteristic of a hyper-had Sony sensor, or a Canon equivalent.
I think it's not the lens, because it doesn't show up all over the image, only on the over-exposed highlight boundary.

Strange that I was just reading about 'purple fringing and chromatic aberation' just before looking at this thread. Mostly because I had some in one place on a recent shot with my D80 and 18-200.
Thankyou for the explanations on the shadows and fringing drg. freygr, and Paul!