matt_moorlag Posted November 21, 2003 Share Posted November 21, 2003 I live in Alaska and the Northern Lights were really intense tonight so I took a few pictures with my digital camera. I used a Fuji S2 and Nikon 80-200 (2.8). I set the camera on manual at F11 and exposed on the bulb setting for approx. 1-2 minutes (tripod and cable release). When I looked at the pictures they all had rings in them. Does anyone have know what this is from and how I can correct it. I plan to do a lot of northern lights photography so any help is greatly appreciated.<div></div> Link to comment Share on other sites More sharing options...
stefanovandelli Posted November 21, 2003 Share Posted November 21, 2003 This is weird. I've never seen anything like it, but I would guess that it is caused by the optics. If you were using a filter, try removing it. Link to comment Share on other sites More sharing options...
bleck Posted November 21, 2003 Share Posted November 21, 2003 Looks like Newton Rings to me... similar to what you get from some flatbed scanners. Were you using a filter? Link to comment Share on other sites More sharing options...
matt_moorlag Posted November 21, 2003 Author Share Posted November 21, 2003 The only filter I used was the B+W U/V filter that I always use to protect the lens. Link to comment Share on other sites More sharing options...
stefanovandelli Posted November 21, 2003 Share Posted November 21, 2003 The filter might be touching the centre of the lens.I have seen this happening with some lenses.Remove the filter and do a test. Link to comment Share on other sites More sharing options...
greglyon Posted November 21, 2003 Share Posted November 21, 2003 It looks like a moiré to me. <i>This is speculation:</i> Does the S2 have an anti-aliasing filter? Could it have something to do with condensation on the anti-aliasing filter? Related questions would be: How cold was it outside? Had your camera been in the cold long when this shot was taken? Link to comment Share on other sites More sharing options...
greg_erker Posted November 21, 2003 Share Posted November 21, 2003 I think you have tested the optical flatness of your camera's AA filter. The aurora light is probably single freqency so you are seeing interference patterns between the top and bottom surfaces. If you have a filter on the camera (especially if it's uncoated) then that is a suspect too. Greg Link to comment Share on other sites More sharing options...
greg_erker Posted November 21, 2003 Share Posted November 21, 2003 You can see interference patterns like this if you are ever in a restaraunt or bar at night and they have neon light signs inside. Look at the reflections of the sign in a window and you can see the interference patterns caused by the reflections off the inside and outside surface of the glass. This happens because the neon light is fairly monochromatic (just like your green northern lights I'd guess). I used to make holograms (which is all about interference patterns) and so I tend to look for them in normal life. Greg Link to comment Share on other sites More sharing options...
matt_moorlag Posted November 21, 2003 Author Share Posted November 21, 2003 Greg, It was about 5 degrees F when I took it. The camera had been in the cold for about 45 minutes. I also took it inside for about 30 seconds to change batteries before I realized that it wasn't very smart to do that and took it back outside. Thanks for your input. Link to comment Share on other sites More sharing options...
gsbhasin Posted November 21, 2003 Share Posted November 21, 2003 Matt,<p>I dont know the answer to your question, but the photo has a very pschadelic look to it. Very cool, like something from the X-files. Link to comment Share on other sites More sharing options...
jespdj Posted November 22, 2003 Share Posted November 22, 2003 Greg Lyon wrote:<br> <i>"It looks like a moiré to me. This is speculation: Does the S2 have an anti-aliasing filter? Could it have something to do with condensation on the anti-aliasing filter? Related questions would be: How cold was it outside? Had your camera been in the cold long when this shot was taken?"</i> <p>This is not moiré; moiré is an aliasing effect and you see it on photos of things that have a fine pattern. The sky doesn't have such a fine pattern. These are Newton rings, and it must be an effect in your filter or lens. Link to comment Share on other sites More sharing options...
erb_duchenne Posted November 22, 2003 Share Posted November 22, 2003 I'd agree with Greg on interference. The lights are caused by an electron bombardment on the atmosphere. Electrons do crazy things. Probably some kind of tangential radiation. Of course, I'm just fishing. Link to comment Share on other sites More sharing options...
greglyon Posted November 22, 2003 Share Posted November 22, 2003 I knew I was out on a limb with my moire suggestion, I was imagining discreet drops in a regular pattern forming on the anti-aliasing filter. Of course, even in the unlikely event that THAT happened it would create a regular repeating pattern instead of the concentric circle pattern in the sample photo... Matt, just curious, has that pattern been repeated in other images? Link to comment Share on other sites More sharing options...
matt_moorlag Posted November 22, 2003 Author Share Posted November 22, 2003 Greg, This is the first time I've had this happen, however its also my first time shooting northern lights with this camera. I took 6-8 pictures and about half of them show the rings. The remainder were taken in a different direction and don't display them. On our next clear night I'll try it without the U/V filter and see if it makes a difference. Thanks for your input. Link to comment Share on other sites More sharing options...
greg_erker Posted November 23, 2003 Share Posted November 23, 2003 Searching for "interference patterns in aurora photos" on google got me <a href="http://216.239.57.104/search?q=cache:DMTd7PECHFgJ:www.ptialaska.net/~hutch/aurora.html+interference+patterns+in+aurora+photos&hl=en&ie=UTF-8">this hit</a>. <p> Sounds like your filter is the problem. <p> The second hit is a similar discussion to this one on none other than photo.net. <p> Greg Link to comment Share on other sites More sharing options...
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