Forgot Password
Pentax Camera Forums Home
 

Reply
Show Printable Version Search this Thread
02-10-2016, 02:30 PM   #31
GUB
Loyal Site Supporter
Loyal Site Supporter
GUB's Avatar

Join Date: Aug 2012
Location: Wanganui
Photos: Gallery | Albums
Posts: 2,554
QuoteOriginally posted by BigMackCam Quote
Well, the more northern parts of Scotland are the best for UK viewing, as I understand it - though we *can* occasionally see it from areas of Northumberland, just a little further north of where I live... But it's cold and wet here right now - so my offer of lenses, Blu-Tak and spearmint gum stands!
Yes your weather has made it on the news down here

---------- Post added 02-11-16 at 10:42 AM ----------

QuoteOriginally posted by DagT Quote
No, this is NOT Newton rings. Newton rings are uneven and require contact between two surfaces. The phenomena you see in these pictures show rings distributed form the optical axis being gradially closer together. You get this from two parallel surfaces being spaced apart, often in UV filter, and only when the light is (almost) monochromatic, like in the Aurora. The effect is related to socalled Fabry-Perot filtering. You can see an explanation here
http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/fabry.html
and a picture of the rings here as well as more explanation here:
https://en.wikipedia.org/wiki/Fabry–Pérot_interferometer

PS: Take the UV filter off and try again :-)
Great stuff -- it is fascinating.
I am trying to get my head around the resulting optics--- If you looked through the filter with your naked eye at the aurora, would the effect be visible? (filter at hand length)


Last edited by GUB; 02-10-2016 at 02:44 PM.
02-10-2016, 02:49 PM   #32
Forum Member




Join Date: Sep 2012
Location: Oslo
Posts: 57
It should be, but that depends on the contrast. I used a high quality Fabry-Perot for my masters degree in optics, and then the patterns were clearly visible, but the UV-filter is noe very high quality as an interferometer so the contrast may be low.

A lot of parameters come in play here. Very good filters are plane, which would increase the effect, but if the anti reflection coating is good at the relevant wavelength it will reduce the effect.
02-10-2016, 03:12 PM   #33
GUB
Loyal Site Supporter
Loyal Site Supporter
GUB's Avatar

Join Date: Aug 2012
Location: Wanganui
Photos: Gallery | Albums
Posts: 2,554
QuoteOriginally posted by DagT Quote
It should be, but that depends on the contrast. I used a high quality Fabry-Perot for my masters degree in optics, and then the patterns were clearly visible, but the UV-filter is noe very high quality as an interferometer so the contrast may be low.

A lot of parameters come in play here. Very good filters are plane, which would increase the effect, but if the anti reflection coating is good at the relevant wavelength it will reduce the effect.
Probably a dumb question but would anti reflective coating affect the internal reflection here.
02-10-2016, 03:21 PM   #34
Pentaxian




Join Date: Jul 2009
Location: Tromsø, Norway
Photos: Albums
Posts: 956
I shoot lots of aurora with my K-5, but I have never gotten those rings. Although I never tried the Tamron 17-50/2.8, I use lots of other lenses for aurora. Sigma 18-35/1,8, Tamron 10-24, Samyang 8/3,5, and sometimes Pentax 18-55 WR and 18-135 WR.

That leads me to think it must be lens related.

02-10-2016, 03:23 PM   #35
GUB
Loyal Site Supporter
Loyal Site Supporter
GUB's Avatar

Join Date: Aug 2012
Location: Wanganui
Photos: Gallery | Albums
Posts: 2,554
QuoteOriginally posted by Simen1 Quote
I shoot lots of aurora with my K-5, but I have never gotten those rings. Although I never tried the Tamron 17-50/2.8, I use lots of other lenses for aurora. Sigma 18-35/1,8, Tamron 10-24, Samyang 8/3,5, and sometimes Pentax 18-55 WR and 18-135 WR.

That leads me to think it must be lens related.
Do you use a filter?
02-10-2016, 03:28 PM   #36
Moderator
Loyal Site Supporter
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 6,676
QuoteOriginally posted by GUB Quote
Do you use a filter?
Did we determine that the OP used a filter? I can't recall...
02-10-2016, 03:45 PM   #37
GUB
Loyal Site Supporter
Loyal Site Supporter
GUB's Avatar

Join Date: Aug 2012
Location: Wanganui
Photos: Gallery | Albums
Posts: 2,554
QuoteOriginally posted by BigMackCam Quote
Did we determine that the OP used a filter? I can't recall...
He didn't say. From what DagT says it pretty well has to be the filter.
02-10-2016, 03:55 PM   #38
Loyal Site Supporter
Loyal Site Supporter
clackers's Avatar

Join Date: Jul 2013
Location: Melbourne
Photos: Albums
Posts: 9,025
QuoteOriginally posted by DagT Quote

PS: Take the UV filter off and try again :-)
Yep, there's a bin right over there! 😀

02-10-2016, 03:55 PM   #39
Moderator
Loyal Site Supporter
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 6,676
QuoteOriginally posted by clackers Quote
Yep, there's a bin right over there! 😀
Just pass them right over here, folks... to my home for unloved UV filters...
02-10-2016, 04:07 PM   #40
Pentaxian




Join Date: Jul 2009
Location: Tromsø, Norway
Photos: Albums
Posts: 956
QuoteOriginally posted by GUB Quote
Do you use a filter?
No, I never use filters when shooting aurora.
02-10-2016, 04:35 PM   #41
GUB
Loyal Site Supporter
Loyal Site Supporter
GUB's Avatar

Join Date: Aug 2012
Location: Wanganui
Photos: Gallery | Albums
Posts: 2,554
QuoteOriginally posted by Simen1 Quote
No, I never use filters when shooting aurora.
OK I might be stubborn as a pig but is there any reason why this wouldn't happen at the sensor array filters? After all they would be built to a higher precision than an aftermarket one. And it would keep me happier about the sharpness of the image.
It would mean of course that Simen1 should get them though.
02-10-2016, 04:40 PM   #42
Moderator
Loyal Site Supporter
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 6,676
QuoteOriginally posted by GUB Quote
OK I might be stubborn as a pig but is there any reason why this wouldn't happen at the sensor array filters? After all they would be built to a higher precision than an aftermarket one. And it would keep me happier about the sharpness of the image.
It would mean of course that Simen1 should get them though.
Film... remember the *film*...
02-10-2016, 04:55 PM   #43
GUB
Loyal Site Supporter
Loyal Site Supporter
GUB's Avatar

Join Date: Aug 2012
Location: Wanganui
Photos: Gallery | Albums
Posts: 2,554
QuoteOriginally posted by BigMackCam Quote
Film... remember the *film*...
Yeah yeah I know but the only image I saw from film was bigger and softer.
And there is a uv filter layer on film.
Hopefully DagT will get back -- he has been playing with this effect.
02-10-2016, 06:12 PM   #44
Loyal Site Supporter
Loyal Site Supporter
clackers's Avatar

Join Date: Jul 2013
Location: Melbourne
Photos: Albums
Posts: 9,025
QuoteOriginally posted by BigMackCam Quote
Just pass them right over here, folks... to my home for unloved UV filters...
That's a quite a yard of strays you've got there!

The 49mm ones are so cute ... those 77mm ones, everyone thinks they're great but they need a lot of exercise or they take it out on your couches. ☺
02-10-2016, 06:24 PM - 1 Like   #45
Moderator
Loyal Site Supporter
Loyal Site Supporter
BigMackCam's Avatar

Join Date: Mar 2010
Location: North East of England
Posts: 6,676
QuoteOriginally posted by clackers Quote
That's a quite a yard of strays you've got there!

The 49mm ones are so cute ... those 77mm ones, everyone thinks they're great but they need a lot of exercise or they take it out on your couches. ☺
Send just ten bucks a month and you can adopt a filter of your choice. You'll receive regular photos taken with your adopted filter and a hand-written letter keeping you informed of their progress...
Reply

Bookmarks
  • Submit Thread to Facebook Facebook
  • Submit Thread to Twitter Twitter
  • Submit Thread to Digg Digg
Tags - Make this thread easier to find by adding keywords to it!
28mm, air, aurora, blur, camera, circles, distortions, effect, explanation, filter, interference, lens, light, manual, newton, night, pattern, pentax help, photography, photos, rings, sensor, source, surfaces, troubleshooting, uv
Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Weird line on photos. Where's the problem? kmhtax Troubleshooting and Beginner Help 22 03-19-2014 10:35 PM
Weird night behavior of pentax-a 50/1.7? malenisjaj Pentax SLR Lens Discussion 9 03-12-2014 04:23 PM
Ricoh GR circular rings artifacts in the pictures seyfer Ricoh GR 6 09-05-2013 07:54 AM
16-45 weird night flare? SMeK Troubleshooting and Beginner Help 18 12-24-2010 06:04 AM
Some weird weather last night Heinrich Lohmann Post Your Photos! 16 06-26-2007 09:04 PM



All times are GMT -7. The time now is 05:34 AM. | See also: NikonForums.com, CanonForums.com part of our network of photo forums!
  • Red (Default)
  • Green
  • Gray
  • Dark
  • Dark Yellow
  • Dark Blue
  • Old Red
  • Old Green
  • Old Gray
  • Dial-Up Style
Hello! It's great to see you back on the forum! Have you considered joining the community?
register
Creating a FREE ACCOUNT takes under a minute, removes ads, and lets you post! [Dismiss]
Top