Double Exposure on a digital camera - strange pic???

One of the lads on another message board posted this pic he took with his digital camera:

Picture 1

Is anyone able to explain what’s going on here? Is it an optical effect, or a glitch in the digital signal processing?

Or is it paranormal?? Interestin’ly the TV programme shown is called “Most Haunted Live”. Could the screen refresh rate on the TV have something to do with it?

It’s deffo not a wind-up btw - just can’t work out wot’s happening with the pic cos it’s no obvious how a digicam can do double exposure.

Thanks!

I wonder if this type of image is possible if the camera is moving when the pic is taken. I know next to nothing about photography, digital or otherwise, so I’m just brainstorming here.

We just did an experiment and were able to duplicate the layered-TV-frames effect with our own digital camera by moving the camera while taking the picture. If you were to have a flash fire at one end of the exposure it would freeze the background in focus as seen in the OP’s photo.

I tend to agree with racinchikki’s explanation but I’ll have to experiment with it myself and let you know.

FWIW discreet double exposures are normally not possible in digital cameras as in film cameras. Once the shutter closes the image is written to a file and any subsequent exposure would be a new file that would have to be combined in post production.

Woohoo! I guessed right. Thanks for doing the experiment, racinchikki.

I happen to come across this, which made me think of this thread. More strangeness from a digital camera.

http://forums.dpreview.com/forums/read.asp?forum=1010&message=7072175

racinchikki can you explain in more detail how you reproduced the OPs image? I also tried to reproduce the image with my digital camera but was not successful. With flash on, it just “froze” the image in my movement, producing no blur at all. With flash off, the entire picture was blurred.

Trigonal: With an automatic camera, when you use the flash it’ll only expose for the flash, and freeze the image as you said. To get the multiple screen images, you have to have a longer exposure, but still fire the flash to freeze the background. You also have to be moving pretty fast; I couldn’t get the images to seperate that much, but I was using racinchikki’s automatic digital camera; I’ll try again when I get a chance with the Nikon D1 pro SLR I use at work. You definitely need a fully adjustable camera and good timing for it to work properly, but it’s possible. I’d think it would be rather hard to accidentally do it, though.

Where did that face in the bottom right come from? It’s not in any of the other images.

Upon closer inspection, I’m not entirely convinced that it’s a “real” photo (might be a Photoshop-assisted “double exposure”).

The one Revtim linked to is an interesting effect that happens with film cameras, too – look up some WWII-era photos airplanes in flight (I can even tell what kind of camera was used by the way the prop blurs). Here’s a diagram somebody posted later in the same thread that explains it. The red line represents the shutter opening.

Here’s a vintage example of the effect Revtim mentioned, taken by a camera whose shutter moved from the bottom of the image to the top, most likely made by Graflex. Graflex cameras had focal-plane shutters that went from the top of the camera to the bottom (the image is projected upside-down on the film, remember) across 4 inches of film (which gives it enough time to exaggerate the bending), and had something like 90% of the civilian newspaper market and extensive military contracts.

(I have a Graflex camera, but the one time I had a chance to duplicate that effect, I couldn’t get in position before they shut off the engines. :pout: )

Okay, my theory - long exposure with flash.

I have some limited understanding of professional photography, but I understand that camera flashes can be set to go off at either the beginning or end of the shutter opening. IE:
(flash…) or
(…flash) (There’s some technical name for this… leading and trailing or something)

The television produces it’s own light, and the progressive pixel scan would lead to a skewed image like that if the camera was moved with the shutter open.

The flash illuminated the wall and door instantaneously at either the beginning or end of the shutter cycle, and that’s why they’re captured without smearing.

It’s flashed, but not in the way everybody else is explaining it.

The background and the TV have one flash exposure. You can even see flash glare on the upper left-hand corner of the TV in the background.

The four CRT images, though, no way in hell those were flashed to produce this image. Flash would just completely obliterate the TV screen, and you should have more of a “smearing” effect from the screen exposure.

So how’s it done? I’m not entirely sure. It was definitely a long exposure – there are no scanlines on the TV, suggesting a shutter speed of 1/15 or slower for that part of the image. You COULD get that sort of effect if you place a piece of cardboard in front of your lens and cover and uncover as you move the camera. Though you’d be insanely lucky to get such a neat effect.

I would guess it’s either a Photoshop-assisted multiple exposure or perhaps some weird digital artefact as explained by Nanoda. (Though I’ve never heard of a digital camera doing this.) By the way, the technical name is rear-curtain flash and slow-sync flash for what you described in your second paragraph.

Just some thoughts.

It’s a different frame in the TV show being displayed by the TV.

Thanks for the replies!

I’m fairly sure the image hasn’t been manipulated in photoshop - it’s more likely a completely random ‘fluke’ shot.

I’ll see if the lad who took the pic in the first place can remember what he was doing when the pic was taken and will post back later.

– e-logic

Most digital cameras have a “Slow Flash” setting. This fires the flash at either the beginning or the end of a long exposure. This is clearly the setting that was used here: the room was fairly dark, so only the TV picture was exposed, except for the instant where the flash fired and “froze” the background.

The camera must have been moving fast to get the separation between frames of the TV image. You could work out how fast, if you knew the refresh rate of the TV screen. In the UK I think it is 60Hz.

Guys I’m no photo-geek so take this for what it’s worth. I have an inexpensive digital camera made for my PC. It takes photos as well as short video clips.
I can also freeze frame these clips and print still photos from the video. The problem I’ve found is that when I shoot a clip while the camera is moving, and/or the subject is moving too fast, when I try to print individual frames I can’t always separate the images to a single subject. It looks very much like the photo in the OP.

I’m sure you guys know more about this stuff than I do. But just in case y’all didn’t have any experience such as this, well there ya are.

I’m guessing that better digital cameras and PC software are capable of faster speeds.

Using my Canon A60 set with one third of a second exposure at F2.8 with flash (which fires at the beginning of the exposure) I have produced an effect similar enough to convince me that this is exactly what happened.

Flickering light-source + long exposure + camera moves ==> several superimposed exposures of the light-source.

Obvious really.

Took me twenty shots to get it exactly right (you have to move the camera pretty damned fast), however, some of the shots are cool!

Just need to get some bendy windmills and my life is complete.

Hi! Im the guy who took the picture.
It was taken on New Years Eve and to be honest, i was that drunk i dont remember taking it! It was the next day i discovered it. I have in no way used photoshop to alter anything.
The camera is a basic Polaroid PDC3035 and as far as im aware it has no manual shutter speed on it.
Let me know if you have any other questions
Neil

It’s called front curtain or rear curain sync and refers to focal plane shutters though nothing really prevents it from being used with leaf or hybrid electronic shutters. Normal mode is for the flash to fire when the first curain is completely open. This is fine for the most part unless you want a long exposure with a trailing ghost image of any movement. You’d switch to flash at the end to give the illusion of movement. Shooting this way with front curtain sync makes the ghost trails appear backwards.