Hey people, what caused this "whatever it is"

[episodic]

http://farm2.static.flickr.com...05949_eeac3fd8da_b.jpg


I took a series of pictures in a cave. It was very dark, no tripods allowed, so I bumped the ISO to 800 and braced myself.

The noise I was ready for, but what are those bright round spots? At first I freaked and thought something was on the lens, but there isn't.

I was real edgy taking the camera down there, the humidity was really high.


Not all shots did this, but alot did.


Reflections? Alot of the walls were glistening and damp. . .

 

[troytime]

some people believe those "orbs" are ghosts/spirits

i believe they're reflections from dust or moisture in the air (caused by flash or other concentrated light)

 

[episodic]

Well, the place was certainly moist I was using the flash at maximum output. So it makes sense.

 

[fuzzybabybunny]

Yeah, the only thing I can think of is backscatter.

wikipedia:

The term backscatter in photography refers to light from a flash or strobe reflecting back from particles in the lens' field of view causing specks of light to appear in the photo. Photographic backscatter can result from snowflakes, rain or mist, or airborne dust. Backscatter is particularly a problem in underwater photography, where particulate matter can be very dense and include plankton which would otherwise be near transparent.

Backscatter can be reduced by offsetting the direction of the photo strobe as far from the angle of the lens as possible. This is normally done by placing the light source high and to one side by placing the strobe on an extendable strobe arm. By having the light come from the side, the reflected light is primarily in the direction of the strobe instead of the camera lens. This is similar to comparing a full moon to a half moon. The full moon is when the moon is lit from almost behind the earth, creating reflection off the whole surface facing the earth. A half moon is when the moon is being lit from one side, making the reflection half the size and the light intensity much less. In photography, the side lighting makes the backscatter less pronounced.

Backscatter can often also be removed digitally after the photo is taken with photo editing software using digital filters or cloning of areas of the photo near the backscatter spots.

 

[dug777]

As has been said, backscatter, and it's a real pita underwater.