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View Full Version : Why Are The Lights Doing This ?



sanger
13-03-2017, 9:06am
Any idea why the lights on this jetty appear as they do.
Have taken similar before without this.
Is it wind, sea mist etc. ?
I think the EXIF should show but,
6.40am
D3100
18-55 lens
5/2 sec
f9
38mm
iso 800 ( which was changed back to 100 once I realised )
Cheers
:confused013:)

ameerat42
13-03-2017, 9:35am
Nice image, Sanger. Pity it is an annoyance.
Notice that the streaking doesn't occur in the reflected lights
on the water.

I get streaks like this with my phone when there is a bright central-ish
source (recently, on a downlight in the ceiling). I can only put it down to
light bouncing off some internal parts of the camera when the aperture is
at a pretty wide setting. However I'm still :confused013 about it.

A search on Google has lots of the same Qs asked and as many arm-waving
replies. I'd guess: try the same thing with your more controllable camera,
setting the aperture progressively from wide to narrow for each shot. You might
be instrumental in providing a definite reply.

ricktas
13-03-2017, 9:59am
what is 5/2 of a second? Did you mean 2.5 second exposure?

Do you have any sort of filter on the lens used?

ameerat42
13-03-2017, 10:11am
Hmm! Having had another - better - look at the exif, I see it was taken at f/9.
That almost suggests an answer to me:
It is caused by diffraction of the bright lights through the very small aperture that f/9
would give on a f=30mm lens - viz, about 3mm. Now, why they are aligned like that is
another thing. I bet, though, that the angle of the camera to the lights would have had
some effect, and if you shifted the image in the camera the orientation of the streaks
would change.

- - - Updated - - -

PS: the foregoing is NOT definitive.

sanger
13-03-2017, 10:34am
what is 5/2 of a second? Did you mean 2.5 second exposure?

Do you have any sort of filter on the lens used?

Good pick up...it was 2.5...and no filter.

- - - Updated - - -


Nice image, Sanger. Pity it is an annoyance.
Notice that the streaking doesn't occur in the reflected lights
on the water.

I get streaks like this with my phone when there is a bright central-ish
source (recently, on a downlight in the ceiling). I can only put it down to
light bouncing off some internal parts of the camera when the aperture is
at a pretty wide setting. However I'm still :confused013 about it.

A search on Google has lots of the same Qs asked and as many arm-waving
replies. I'd guess: try the same thing with your more controllable camera,
setting the aperture progressively from wide to narrow for each shot. You might
be instrumental in providing a definite reply.

Hmmm...There was a big bright light at the start of the jetty behind me.
Must go back and try to solve.

- - - Updated - - -


Hmm! Having had another - better - look at the exif, I see it was taken at f/9.
That almost suggests an answer to me:
It is caused by diffraction of the bright lights through the very small aperture that f/9
would give on a f=30mm lens - viz, about 3mm. Now, why they are aligned like that is
another thing. I bet, though, that the angle of the camera to the lights would have had
some effect, and if you shifted the image in the camera the orientation of the streaks
would change.

- - - Updated - - -

PS: the foregoing is NOT definitive.

Maybe because I was down low looking up.
I shall practice :)

ricktas
13-03-2017, 2:20pm
You mentioned that this was at ISO 800, when you changed it back down, did this anomaly still occur?

sanger
13-03-2017, 5:49pm
You mentioned that this was at ISO 800, when you changed it back down, did this anomaly still occur?

Yep, same at f11, iso 100

ameerat42
13-03-2017, 5:51pm
Then I wonder how they'll go with the aperture more open?:confused013

sanger
13-03-2017, 6:04pm
Then I wonder how they'll go with the aperture more open?:confused013

20 mins later

ricktas
13-03-2017, 6:44pm
it looks quite dull, was there a seamist or slight fog about? It could be the light refracting of mist that only shows up more as you extend the time the shutter is open

sanger
13-03-2017, 9:07pm
it looks quite dull, was there a seamist or slight fog about? It could be the light refracting of mist that only shows up more as you extend the time the shutter is open

Yep I wondered about sea mist which I noted in the first post.
It wasn't windy but I was close to the water with the wash coming close to me....it got me and the tripod a couple of times.

wmphoto
14-03-2017, 8:59pm
Dirty lens with a smudge mark being more sensitive to the brighter lights than the reflected ones in the water?

sanger
14-03-2017, 9:40pm
Dirty lens with a smudge mark being more sensitive to the brighter lights than the reflected ones in the water?


I reckon that's it or lens damage...went to the jetty tonight and same had the same issue but not on another lens or my phone.