black dot on the sun

M

MatRich

Carbonite Member
hi I have seen some videos in sport films where there is a black dot in the middle of the sun. I would like to know how this happens so I can avoid doing this if it is possible.

thank you!
 
It is likely an electronic artifact of the imaging device and/or the video electronics overloading because of the very high intensity directly looking at the sun. Since we don't know exactly what camera (or kind of camera) produced the effect a more specific answer is not possible.

I would be pretty upset if anybody aimed one of MY cameras at the sun. Generally speaking, NEVER EVER point a camera at the sun.
 
so then lowering your exposure would fix the problem.

what types of damages can come from shooting the sun?
 
The early Red Ones had this issue, they called it "sensor protect" IIRC, and yes, it's as Richard says, it's something the chip does to protect itself from serious overexposure.
 
MatRich said:
so then lowering your exposure would fix the problem.

what types of damages can come from shooting the sun?
Click to expand...

PLEASE NOTE: AIMING A CAMERA AT THE FULL SUN IS NEVER A SAFE THING!!! Closing down the iris is NOT a safe way to get a shot of the sun. The only time shooting the sun is relatively safe is early sunrise or late sunset.

Astronomers use indirect means of looking at the sun. They use heavy filters and lenses to project an image of the sun onto a screen like this...

sarah_sungun_sm.jpg


The reason for not shooting the sun is exactly the same as the reason you don't LOOK at the sun with your eyeball. You run a very great chance of physically BURNING the retina of your eye (or the imaging device of the camera). The same effect as mean little boys who incinerate ants with a magnifying glass.

I have a friend who actually burned the LCD viewfiinder screen of his camcorder by carelessly allowing the eyepiece lens to concentrate the sun's rays onto the surface of the screen. It actually burned a hole in it and ruined the viewfinder. Imagine what it would have done to the imaging chip!

No, it is not a protective response, The black dot is actually the video electronics severely OVERLOADING and going so far above white clipping that the video signal "wraps around" and reappears as black. Here is an example of the same effect happening in an audio waveform. The signal goes so far above the upper limit (full-scale) that the numbers "wrap around" back to zero. This is also a common computer programming issue if you don't provide enough space for the largest numbers.

clipfix_demo.JPG


There is no way for a chip (or your eyeball or my friend's viewfinder or an ant) to "protect" itself except by physically interrupting the beam of sunlight. In the case of the RED camera, likely by auto-irising down the lens.

Remember that there is very considerable POWER in the sun's rays. Way more than enough to physically BURN things when concentrated with any kind of lens. Even a discarded pop bottle or a bead of water can concentrate the sun's rays enough to start a wildfire.

In earlier days of tube video cameras, even aiming a camera at a studio light would burn the image onto the tube surface. It would get one fired on the spot and possibly black-listed as an ignorant camera operator.
 
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Ryan Patrick O'Hara said:
This reminds me of just how flippin' awesome celluloid film is. Hahaha! Point that baby at the sun all day long! Every frame is a new sensor. :)
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Was it the movie "Cinema Paradiso" where they had to tone down the scene :eek:where the film catches fire in the projector? Old-time projectionists (who remembered how explosively flammable celluloid film was) were being freaked out and running screaming from the projection booth. The special effect was very realistic! :eek:
 
Richard Crowley said:
Was it the movie "Cinema Paradiso" where they had to tone down the scene :eek:where the film catches fire in the projector? Old-time projectionists (who remembered how explosively flammable celluloid film was) were being freaked out and running screaming from the projection booth. The special effect was very realistic! :eek:
Click to expand...

Haha, I've never heard of that, but yeah, the old nitrate film was quite explosive. Those poor dead editors who would fall asleep smoking, while cutting the neg. Stupid stupid editors. :)
 
I read the original post the other day and then immediately turned on something along the lines of "Signs of the Apocalypse" on the History Channel and I swear one of the first signs was "the sun turning black" - needless to say I've been too busy building up my apocalypse shelter to respond. But yeah, I've only ever pointed my camera at the sun close to golden hour times, doing so during the day and you might as well name your camera Icarus :P
 
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