What happened with this image?

[Rick Poulin]

I am not sure if this is the right forum to be asking this question but I am not sure where else to ask.

While shooting a series of images of Barn Swallows feeding nestlings I recorded this image.

I was using a Nikon D5100 set on auto with a Nikor 70-300 lens at 280MM, F/5.6, SS 1/60, ISO 3200, Auto Flash.

The image is straight out of the camera with no PP. Not a double exposure that I am aware of.


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[John Chardine]

Hi Rick, My theory is that the bird was moving so fast that you obtained a latent image of the bird but then it moved out of the way and the flash went off and you exposed what was behind the bird as well. The nest looks flashed and the bird does not.

(I erroneously added the following to Rick's post instead of my own. Now it's where it belongs):
This is what happens when you have rear-curtain sync set on the flash- the flash fires at the end of the exposure rather than the beginning.

[arash_hazeghi]

yeah 2nd curtain with a slow shutter speed, at first curtain you got the swallow and at 2nd curtain you got the BG with flash when swallow had moved out of the frame. looks like you answered your own question (?)

[Rick Poulin]

Thank you for your suggestions gentlemen. It makes sense.

Now for a follow up question, is it possible and how do I sync the flash with a D5100?

[Mike Milicia]

This is known as ghosting and can potentially happen anytime you use flash at or below the camera's sync speed. It can happen with front curtain sync as well as rear curtain sync as long as your ambient exposure settings allow any image to be recorded.

One way to avoid it is to set your ambient exposure so that the scene is underexposed to the point where you will get a black frame without the flash. Another way is to shoot at or above the sync speed so that the flash is firing during the entire exposure. Depending on the shutter speed, this latter method may still result in motion blur as the flash is no longer helping to freeze the subject's motion but you will not get ghosting.