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Comment by criley2 | Hacker News Reader

Unless he does not have a timer and instead reduced aperature dramatically (high f/stop) to reduce light, then increased exposure time dramatically.

The result would be a "properly exposed" shot for anything except what was moving during the shot, which would presumably be him running so he could stand still and be exposed during the already running exposure.

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I used to get this effect in the 80's with an Olympus OM-1 by setting exposure to automatic with aperture at F16 with strobe flash. In low light, the shutter would open for (say) 1 second, in the middle of which the strobe would flash for a 1000th of a second. The result is relatively crisp subject with a darker ghost. Timer made no difference. For a while, you'd see the effect in commercial photography.

I would imagine that someone working near the elephant's foot would be moving very fast.

If the shutter was open long enough for him to walk around the camera, it would be one giant blur, not spots of blurriness, with two distinct humanoids in the frame.

This article is filled with inaccuracies and/or guesses (as other HN'ers are pointing out in other comments).

For example, it's increadibly unlikely the photographer of this image is still alive. Standing that close to that much radiation for long enough to setup a camera, walk around it and putz around for a while... I don't buy it. Majority of the workers involved in the containment died shortly afterwards, or developed terrible ailments due to extreme radiation exposure, leading to early death.

To play devil's advocate, this can actually be easily achieved with a timer delay, a shutter drag AND a flash.

I don't believe that would explain the two distinct humanoid figures, with little motion blur between them. The person would have had to move extremely quickly from bent-over to up-right (almost instantly as the shutter opened) and held that position. Seems unlikely.

In addition, maybe it's just the lighting effects, but the figure standing almost upright is wearing what appears to be a yellow jumpsuit, while the figure bending over is wearing white. The red box on their hip is probably some sort of geiger counter, and most folks getting this close probably had one.

The photo was taken 10 years after the initial meltdown and photographer is alive. When the meltdown first happened, anyone that close would be dead under 2 minutes. The radiation figures are in the article.

If were to take a 10 second photo, 4 seconds in one spot, 1 second moving and another 5 seconds in another spot I wouldn't be a full blur. The part of me moving only accounts for 1/10 of the entire exposure and the places where I stood still would be much brighter. I can exaggerate this by turning off my flash light when I was moving.

This article[1] seems to believe it was multiple workers who took this photograph (and this source is a bit more credible imho), and notes it's still deadly to be in close proximity for more than 2 minutes.

Your explanation still doesn't explain the lack of motion blur walking over to the spot, although we see the flashlight(s) blur. There also appears to be two distinct flashlight blurs.

[1] http://nautil.us/blog/chernobyls-hot-mess-the-elephants-foot...

You're right in that we don't know how the photo was taken but a long photo exposure doesn't necessarily mean you will see his trail. My explanation still stands a pure guess of how that photo could have been taken. Let me explain more:

There is only so much range a piece of film can achieve. I don't know how much you know about photos but exposure and light are usually discussed on a log(base 2) scale. Each exposure "unit" called a "stop" equates to doubling or halving the amount of light. So a 4 second exposure is 1 stop darker than an 8s one because it lets in half the light.

Assuming there are no other light sources we can assume the entirety of the exposure came from the flash light. There is a shadow behind and above the elephants foot which tells us the elephants foot was illuminated by a light below the camera. Assuming the guy had the camera at almost eye level, shines the flashlight at waste level could produce this kind of shadow.

Now let's say the guy turns the flashlight off walks over to where he is in the photo and starts moving the flash light more, shift position and does it again. You will not see him walk to the spot in the photo even if the room was not completely dark.

If he took a 60 second photo, he set the exposure for 30ish seconds of light from flash light and not from ambient light. This means the ambient light reflecting off the guy while he walked probably exposed a trail that is over 10 stops below what the light from the flash light did. In good conditions your average color negative film has about 7 stops of dynamic range or +3 from middle tones before turning completely white and -3 from going to complete black. It's not hard to set up a photo where you don't register because you're trail exposes below the range of the film. Many people do these kinds of photos and they are called "lightpainting".

This is very commonly done in landscapes where certain features of landscapes like trees and rocks are painted. You don't see the people walking around because they turn their lights off when they do it. They do produce walking smears but they account for such a small proportion of the overall exposure they don't show up in the final photo. I believe this what these guys do and notice no people in their photos:

http://www.lightmark.de/overview.html

However they might compositing images. Here is another example:

http://cache3.asset-cache.net/gc/554997063-glowing-digital-m...

I've personally done photos like that in a single long exposure. I'm sure the photos I linked have lots of photoshop to get them perfect to get them perfect the principal stands. I'm assuming a lot of photography sophistication that the elephant foot photographer may or may not have but how knows!

Even with a proper exposure including a shutter speed as short as 30 seconds, a person walking in front of the camera won't show up unless they stand still. You can use that technique to take a picture through a busy sidewalk and see the people vanish on the image. The image also appears to be lit by a small work-light on camera right (note the hard shadow of the foot and the reflection on the man's helmet). He could have walked in the shadow and stopped in the light to increase that "vanishing" and reappearing effect (similar to how you might use a long shutter speed to blur a background while using a flash to "freeze" the subject).

Doing some back of the envelope calculations, with a somewhat bright room, you could take the exposure in anywhere from 15s to 2m which is plenty of time to walk across the room.

Of course all this is irrelevant because timers (mechanical and electronic) had been standard features in cameras for decades by 1996. It looks to me like he just moved in the midst of a 2 or 3 second exposure.

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