Unusual street scenes

[megrag]

I took this photo while on a "Ghost Tour" in Asheville, N.C.. It is pretty much straight out of the camera, an A620. It was cropped from a larger phot, but no photoshop tricks or any post processing. Not quite sure what happened to the head. Anyone have any explanations??

IMG_8313tlc.jpg

[Dave Humphries]

Hi Greg,

Very intriguing (sp?), given the info on where you took it

Dunno if it will spoil the fun, but at least everyone will start from the same point; the EXIF is:
Canon Powershot 620, 1.3 seconds at f4, iso200

Cheers,

[KentDub]

I took this photo while on a "Ghost Tour" in Asheville, N.C.. It is pretty much straight out of the camera, an A620. It was cropped from a larger phot, but no photoshop tricks or any post processing. Not quite sure what happened to the head. Anyone have any explanations??

I'll give it a shot. When doing long exposures, the camera will record the brightest moment the pixel ever gets. The background is brighter than the man's shirt - so you "see through it". The man's face is brighter than the background, so it smears. Simple enough? The lightest object wins

[megrag]

I'll give it a shot. When doing long exposures, the camera will record the brightest moment the pixel ever gets. The background is brighter than the man's shirt - so you "see through it". The man's face is brighter than the background, so it smears. Simple enough? The lightest object wins

Very interesting explanation, KentDub. I did not know this. I still prefer to think of it as a ghost though. It's more fun that way.
Greg

[David]

Hi Megrag - I agree with KentDub, more or less. His explanation is a simple way of looking at the idea. Another way is to think of an individual pixel in your camera's sensor. During a long exposure, the response that it will register will be the weighted sum of all the light that came into it. If there was constant illumination you get the normal response, but if something bright came into view for a short period of the exposure, then the response would increase in proportion to the time of the bright object being in view. It works the other way round as well. Thus, if you have a moving object such as a car that has relatively low luminance compared to its tail-lights (say) then a long exposure may show the tail-lights moving across the frame, but no car! I think there was some award winning art photographer who took this idea to extremes. He (or she?) would set up the camera at a busy traffic junction in broad daylight and, presumably using filters, take extraordinarily long exposures (several minutes). Despite cars and pedestrians, the shots showed the junction as if nothing was there. (Okay, I don't know why he/she did it either but then I'm not that arty!)

Cheers

David

[megrag]

Hi Megrag - I agree with KentDub, more or less. His explanation is a simple way of looking at the idea. Another way is to think of an individual pixel in your camera's sensor. During a long exposure, the response that it will register will be the weighted sum of all the light that came into it. If there was constant illumination you get the normal response, but if something bright came into view for a short period of the exposure, then the response would increase in proportion to the time of the bright object being in view. It works the other way round as well. Thus, if you have a moving object such as a car that has relatively low luminance compared to its tail-lights (say) then a long exposure may show the tail-lights moving across the frame, but no car! I think there was some award winning art photographer who took this idea to extremes. He (or she?) would set up the camera at a busy traffic junction in broad daylight and, presumably using filters, take extraordinarily long exposures (several minutes). Despite cars and pedestrians, the shots showed the junction as if nothing was there. (Okay, I don't know why he/she did it either but then I'm not that arty!)

Cheers

David

You guys really broke my heart. I thought I had really seen a ghost!!! After all it was on a "GHOST TOUR"
Greg

[KentDub]

You guys really broke my heart. I thought I had really seen a ghost!!! After all it was on a "GHOST TOUR"
Greg

Maybe we're wrong... You should submit this to the SyFy channel!

[Dave Humphries]

~ He (or she?) would set up the camera at a busy traffic junction in broad daylight and, presumably using filters, take extraordinarily long exposures (several minutes). Despite cars and pedestrians, the shots showed the junction as if nothing was there. ~

Sounds like something for Colin to try and show us the results (I'm gonna regret that )



Mind you, in (my mind's imagination of) NZ (lot of land, few people), would he even see a car within the exposure time anyway?

How big is a Nelson rush hour?

[Colin Southern]

Sounds like something for Colin to try and show us the results (I'm gonna regret that )

Long exposures essentially "average" the scene, so if a car takes, say, 1 second to pass through a point and that happens every 10 seconds, then the most it's going to contribute is 10%. But wait, there's more ...

... us humans like to identify images by isolating edges and surfaces - but with the above scenario these are well and truly "smoothed out".

So the net result is nothing recognisable.

Mind you, in (my mind's imagination of) NZ (lot of land, few people), would he even see a car within the exposure time anyway?

Umm - doesn't quite work that way Dave. Still lots of people in the cities, just far apart in the country.

How big is a Nelson rush hour?

Usually not too bad, unless those of infinite wisdom decide to dig a hole in the road and then fill it in again for no apparent reason (ie "road works") - then we can end up with 10 to 15 minutes to travel 1km

I remember one Christmas road jam where we were passed by the same walker several times (of course with kids in the car chanting "are we there yet? are we there yet? didn't help!) The "good old days" were when I used to fly the plane up to new Plymouth to see my Mum; 1 hour 10 min wheels up to touchdown -v- the other way ... 2 hours drive to Picton - 3.5 hour ferry trip - 5 hour drive (well except for the time where we had a faulty emergency gear extension dump valve and the gear stayed down for the entire flight (yuck, yuck, and tripple yuck!).

[Colin Southern]

PS: Making a good "ghost" shot is pretty easy ...

- Setup your camera on a tripod.

- Take a shot with people in it

- Without moving anything, take a 2nd shot without the people in it

- open both in PS - move one onto the other (so it's stacked as a layer), and vary the opacity to suit and ...

... "job done".