Seeing Double - Seeking a Scientific Explanation

[Brownbear]

Hi John,

Why does a multiple exposure function photo require a lot of editing? My photo of this snake is bad simply because of my technique and mysterious settings. But the snake on the left hand side actually looks better than the real snake. I only saw it because I lightened the shadows, followed by an attempt to see if I could improve it by increasing contrast and sharpening.

The only double thing in the photo is the snake, ie; no double road, shadows or rocks?

Thank you

I have an Olympus 4/3rds that has the multiple exposure function and a Nikon that can do an overlay of two images. The multiple exposure function is fun but requires a bit of editing. You can also do the multiple exposure with a strobe.

[Shadowman]

Hi John,

Why does a multiple exposure function photo require a lot of editing? My photo of this snake is bad simply because of my technique and mysterious settings. But the snake on the left hand side actually looks better than the real snake. I only saw it because I lightened the shadows, followed by an attempt to see if I could improve it by increasing contrast and sharpening.

The only double thing in the photo is the snake, ie; no double road, shadows or rocks?

Thank you

Christina,

It requires more than is used on a standard photo, otherwise the double exposed portion will look ghostly. For some images that is fine, but if you are trying to simulate motion you want parts of the double exposed subject to appear sharp. Also, as in your image sometimes the doubly exposed subject appears in an area with better background contrast so you require more editing to bring out details in multiple sections of the image.

[Brownbear]

Thank you John

[JHzlwd]

Hi (again) Christina,

Thanks for acknowledging. I said something incorrect in my original reply, to the effect the ghost image should be reversed if it was a reflection from the back surface of the lens. In fact, it should be just as you see it in your sample image because it is reversed twice - once as seen facing the lens and then again when facing the camera sensor. It's hard to get close enough to the back surface of the Micro-Nikkor to see how flat it is but I have the Nikon 105 mmm (non-macro) where the back is accessible. It is perfectly flat which would make for a good mirror in some instances.

Best wishes,
jh

[Brownbear]

Thank you Garth.. I suppose I could try to replicate the scenario to see if I can make it happen again, but I think that would be very difficult to do, so I'm not sure... I truly appreciate your sharing your knowledge and insights but the majority think that I must of had my camera set to multiple exposure and the fact that the tail is in a slightly different position does seem to support that.

[barrydoig]

Did you use rear curtain flash and move the camera? This will produce a latent image behind the original image. This can happen if, like me, you fiddle with your flash controls and don't put them back where they were!
Barry

[Brownbear]

Hi Barry,

That's a definite possibility and the EXIF data for the snake photo show that flash was used but not the flash settings. Playing with the flash controls to learn them and forgetting to return to the normal flash setting sounds like something I would do.

Did you use rear curtain flash and move the camera? This will produce a latent image behind the original image. This can happen if, like me, you fiddle with your flash controls and don't put them back where they were!
Barry