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12-06-2015, 06:57 PM   #1
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Interval shooting

Hi
I set up my K3 to do an interval shoot last night. I was using my 28 2.8M lens and set the camera to take 90 images 20 seconds long, on interval composite with a bright setting. What I'm wondering is what caused the concentric cirlces in the center of the shot. any ideas would be helpful.

Thank You
Evan

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12-06-2015, 07:22 PM   #2
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Funny you should ask that. The only time that I've had that happen was with shooting the aurora too!
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12-06-2015, 08:10 PM   #3
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Looks like the focusing screen???
12-06-2015, 08:12 PM   #4
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I definitely do not know if this is the answer, but factors to consider may be SR being on, NR being on, no GPS unit to handle movement/trailing, or just a result of the composite creating something like that out of coincidence when handling the composite data.

I am not that much of an expert in this area, but if you tried similar tests using maybe a single image, a set of 15 composite, and a set of 30 images composite, and see if you get similar "circles" as you did in the 90 image composite, that might tell you if it is a recurring factor.

12-06-2015, 08:16 PM   #5
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I see a similar story here <http://www.dpreview.com/forums/thread/625189?page=3>.

Cheers,
Terry
12-06-2015, 08:23 PM   #6
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Thanks for the ideas. I had the camera set to keep all the previous images and the pattern shows up on all of them, it gets more pronounced as the shoot progresses.
Shake reduction was turned off, and as far as I know the noise reduction has no effect on raw files unless I'm wrong.
If its the focusing screen, why would it show up.
I'm wondering it it's some sort of reflection inside the lens. Quartermaster James I was wondering what lens you used. The exif data just says 15 mm. Maybe it's a problem with using older M series lenses for this type of photography.

Thank you
Evan
12-06-2015, 08:37 PM   #7
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Nothing to really contribute but subscribing as this is very interesting...and, it was aliens

Actually, a couple observations. First, to the OP, it looks like you have a couple bumps of the camera at the beginning and end. Not that this is the cause but just curious if you noticed them. QMJ, you might have some dust on your sensor as there is a reoccurring dark spot.

Anyway, reading that linked thread, I also have to wonder if it is some moire effect since you are both using the K-3. I also see mention that this occurs when using a filter but I don't think eighter of you mentioned using a filter.

Last edited by colonel00; 12-06-2015 at 08:43 PM.
12-06-2015, 08:42 PM   #8
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QuoteOriginally posted by sjovolde Quote
Thanks for the ideas. I had the camera set to keep all the previous images and the pattern shows up on all of them, it gets more pronounced as the shoot progresses.
Shake reduction was turned off, and as far as I know the noise reduction has no effect on raw files unless I'm wrong.
If its the focusing screen, why would it show up.
I'm wondering it it's some sort of reflection inside the lens. Quartermaster James I was wondering what lens you used. The exif data just says 15 mm. Maybe it's a problem with using older M series lenses for this type of photography.

Thank you
Evan
These were taken with the Sigma 10-20 F3.5

12-06-2015, 08:42 PM   #9
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It looks like there was quite a bit of mass movement differential in the center and surrounding center area, whereas the light trails and the lower and near bottom area seem to have good sharpness consistency. The trails seem to have taken the attention of the focus somewhat away from where the "circle" occurred.
12-06-2015, 08:43 PM   #10
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QuoteOriginally posted by tduell Quote
I see a similar story here <http://www.dpreview.com/forums/thread/625189?page=3>.

Cheers,
Terry
Intrigomon. I did have a protective filter on at the time.
12-06-2015, 08:51 PM - 1 Like   #11
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I want to mention metering setting as one more thing, though I am not sure completely if that may be a possible contributor. As Quartermaster James and colonel00 mentioned, a filter or anything else covering the lens could easily cause a spherical "circle" to be created.

Last edited by C_Jones; 12-06-2015 at 09:06 PM.
12-06-2015, 08:51 PM - 1 Like   #12
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Intrigomon, Quatermaster James. I was also using a UV filter. If I get a chance in the next day or so I'm going to try again with the same setup and remove the UV filter to see if it makes a difference. Would be an easy fix if that does it.

Thank you everyone for the information. This forum always amazes me how fast you can get answers to your questions.
Colonel 00 as far as the bumps go, I was shooting on my deck, and was wandering around for the half hour it took to shoot this. Next time I'll have to try stand still.

Evan
12-06-2015, 09:05 PM   #13
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That looks like Newton's Rings. I've never noticed it with my gear, but astrophotography forums have discussions of the problem. Also see https://en.wikipedia.org/wiki/Newton's_rings

Does interval composite save each subframe in addition to the final composite? If yes, do you see the rings in the subframes?
12-06-2015, 09:07 PM   #14
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QuoteOriginally posted by C_Jones Quote
As Quartermaster James and colonel00 mentioned, a filter or anything else covering the lens could easily cause a spherical "circle" to be created.
I'm not sure I want to be pointing a non-WR lens upward into snowfall without one though!
12-06-2015, 09:07 PM - 1 Like   #15
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QuoteOriginally posted by sjovolde Quote
SNIP...UV filter...SNIP
Flat filter plus curved front glass increases the risk of light interference patterns. Sounds more and more like Newton's Rings.
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